Provided by: openvswitch-switch_3.2.2-0ubuntu0.23.10.1_amd64 bug

NAME

       ovs-vswitchd.conf.db - Open_vSwitch database schema

       A  database with this schema holds the configuration for one Open vSwitch daemon. The top-
       level configuration for the daemon is the Open_vSwitch table, which must have exactly  one
       record.  Records in other tables are significant only when they can be reached directly or
       indirectly  from  the  Open_vSwitch  table.  Records  that  are  not  reachable  from  the
       Open_vSwitch  table  are  automatically deleted from the database, except for records in a
       few distinguished ``root set’’ tables.

   Common Columns
       Most tables contain two  special  columns,  named  other_config  and  external_ids.  These
       columns  have  the  same form and purpose each place that they appear, so we describe them
       here to save space later.

              other_config: map of string-string pairs
                     Key-value pairs for configuring rarely used features. Supported keys,  along
                     with  the  forms taken by their values, are documented individually for each
                     table.

                     A few tables do not have other_config columns  because  no  key-value  pairs
                     have yet been defined for them.

              external_ids: map of string-string pairs
                     Key-value  pairs  for  use  by  external frameworks that integrate with Open
                     vSwitch, rather than by  Open  vSwitch  itself.  System  integrators  should
                     either use the Open vSwitch development mailing list to coordinate on common
                     key-value definitions, or choose key names that are likely to be unique.  In
                     some  cases,  where  key-value pairs have been defined that are likely to be
                     widely useful, they are documented individually for each table.

TABLE SUMMARY

       The following list summarizes the purpose of  each  of  the  tables  in  the  Open_vSwitch
       database.  Each table is described in more detail on a later page.

       Table     Purpose
       Open_vSwitch
                 Open vSwitch configuration.
       Bridge    Bridge configuration.
       Port      Port configuration.
       Interface One physical network device in a Port.
       Flow_Table
                 OpenFlow table configuration
       QoS       Quality of Service configuration
       Queue     QoS output queue.
       Mirror    Port mirroring.
       Controller
                 OpenFlow controller configuration.
       Manager   OVSDB management connection.
       NetFlow   NetFlow configuration.
       Datapath  Datapath configuration.
       CT_Zone   CT_Zone configuration.
       CT_Timeout_Policy
                 CT_Timeout_Policy configuration.
       SSL       SSL configuration.
       sFlow     sFlow configuration.
       IPFIX     IPFIX configuration.
       Flow_Sample_Collector_Set
                 Flow_Sample_Collector_Set configuration.
       AutoAttach
                 AutoAttach configuration.

Open_vSwitch TABLE

       Configuration  for  an  Open  vSwitch  daemon.  There  must  be  exactly one record in the
       Open_vSwitch table.

   Summary:
       Configuration:
         datapaths                   map of string-Datapath pairs
         bridges                     set of Bridges
         ssl                         optional SSL
         external_ids : system-id    optional string
         external_ids : hostname     optional string
         external_ids : rundir       optional string
         other_config : stats-update-interval
                                     optional string, containing an integer, at least 5,000
         other_config : flow-restore-wait
                                     optional string, either true or false
         other_config : flow-limit   optional string, containing an integer, at least 0
         other_config : max-idle     optional string, containing an integer, at least 500
         other_config : max-revalidator
                                     optional string, containing an integer, at least 100
         other_config : min-revalidate-pps
                                     optional string, containing an integer, at least 0
         other_config : offloaded-stats-delay
                                     optional string, containing an integer, at least 0
         other_config : hw-offload   optional string, either true or false
         other_config : n-offload-threads
                                     optional string, containing an integer, in range 1 to 10
         other_config : tc-policy    optional string, one of none, skip_hw, or skip_sw
         other_config : dpdk-init    optional string, one of false, true, or try
         other_config : dpdk-lcore-mask
                                     optional string, containing an integer, at least 1
         other_config : pmd-cpu-mask
                                     optional string
         other_config : dpdk-alloc-mem
                                     optional string, containing an integer, at least 0
         other_config : dpdk-socket-mem
                                     optional string
         other_config : dpdk-socket-limit
                                     optional string
         other_config : dpdk-hugepage-dir
                                     optional string
         other_config : dpdk-extra   optional string
         other_config : vhost-sock-dir
                                     optional string
         other_config : vhost-iommu-support
                                     optional string, either true or false
         other_config : vhost-postcopy-support
                                     optional string, either true or false
         other_config : per-port-memory
                                     optional string, either true or false
         other_config : shared-mempool-config
                                     optional string
         other_config : tx-flush-interval
                                     optional string,  containing  an  integer,  in  range  0  to
                                     1,000,000
         other_config : pmd-perf-metrics
                                     optional string, either true or false
         other_config : smc-enable   optional string, either true or false
         other_config : pmd-rxq-assign
                                     optional string, one of cycles, group, or roundrobin
         other_config : pmd-rxq-isolate
                                     optional string, either true or false
         other_config : n-handler-threads
                                     optional string, containing an integer, at least 1
         other_config : n-revalidator-threads
                                     optional string, containing an integer, at least 1
         other_config : emc-insert-inv-prob
                                     optional  string,  containing  an  integer,  in  range  0 to
                                     4,294,967,295
         other_config : vlan-limit   optional string, containing an integer, at least 0
         other_config : bundle-idle-timeout
                                     optional string, containing an integer, at least 1
         other_config : offload-rebalance
                                     optional string, either true or false
         other_config : pmd-auto-lb  optional string, either true or false
         other_config : pmd-auto-lb-rebal-interval
                                     optional string, containing an integer, in range 0 to 20,000
         other_config : pmd-auto-lb-load-threshold
                                     optional string, containing an integer, in range 0 to 100
         other_config : pmd-auto-lb-improvement-threshold
                                     optional string, containing an integer, in range 0 to 100
         other_config : pmd-sleep-max
                                     optional string, containing an integer, in range 0 to 10,000
         other_config : userspace-tso-enable
                                     optional string, either true or false
       Status:
         next_cfg                    integer
         cur_cfg                     integer
         dpdk_initialized            boolean
         Statistics:
            other_config : enable-statistics
                                     optional string, either true or false
            statistics : cpu         optional string, containing an integer, at least 1
            statistics : load_average
                                     optional string
            statistics : memory      optional string
            statistics : process_NAME
                                     optional string
            statistics : file_systems
                                     optional string
       Version Reporting:
         ovs_version                 optional string
         db_version                  optional string
         system_type                 optional string
         system_version              optional string
         dpdk_version                optional string
       Capabilities:
         datapath_types              set of strings
         iface_types                 set of strings
       Database Configuration:
         manager_options             set of Managers
       IPsec:
         other_config : private_key  optional string
         other_config : certificate  optional string
         other_config : ca_cert      optional string
         Plaintext Tunnel Policy:
            other_config : ipsec_skb_mark
                                     optional string
       Common Columns:
         other_config                map of string-string pairs
         external_ids                map of string-string pairs

   Details:
     Configuration:

       datapaths: map of string-Datapath pairs
              Map of datapath types to datapaths. The datapath_type column of the Bridge table is
              used as a key for this map. The value points to a row in the Datapath table.

       bridges: set of Bridges
              Set of bridges managed by the daemon.

       ssl: optional SSL
              SSL used globally by the daemon.

       external_ids : system-id: optional string
              A  unique  identifier  for  the  Open  vSwitch’s  physical  host.  The  form of the
              identifier depends on the type of the host.

       external_ids : hostname: optional string
              The hostname for the host running Open vSwitch. This is a  fully  qualified  domain
              name since version 2.6.2.

       external_ids : rundir: optional string
              In  Open  vSwitch  2.8  and  later,  the  run directory of the running Open vSwitch
              daemon. This directory is used for runtime state such  as  control  and  management
              sockets. The value of other_config:vhost-sock-dir is relative to this directory.

       other_config  :  stats-update-interval:  optional  string, containing an integer, at least
       5,000
              Interval for updating statistics to the database, in milliseconds. This option will
              affect the update of the statistics column in the following tables: Port, Interface
              , Mirror.

              Default value is 5000 ms.

              Getting statistics more frequently can be achieved via OpenFlow.

       other_config : flow-restore-wait: optional string, either true or false
              When ovs-vswitchd starts up, it has an empty flow table and  therefore  it  handles
              all  arriving  packets  in  its  default fashion according to its configuration, by
              dropping them or sending them to an OpenFlow controller  or  switching  them  as  a
              standalone  switch. This behavior is ordinarily desirable. However, if ovs-vswitchd
              is restarting as part of a ``hot-upgrade,’’ then this leads to  a  relatively  long
              period during which packets are mishandled.

              This option allows for improvement. When ovs-vswitchd starts with this value set as
              true, it will neither flush or expire previously set datapath  flows  nor  will  it
              send  and receive any packets to or from the datapath. When this value is later set
              to false, ovs-vswitchd will start receiving packets from the datapath and  re-setup
              the flows.

              Additionally,  ovs-vswitchd  is  prevented from connecting to controllers when this
              value is set to true. This prevents controllers from making  changes  to  the  flow
              table  in  the  middle  of  flow  restoration,  which  could  result in undesirable
              intermediate states. Once this value has been set to false  and  the  desired  flow
              state  has been restored, ovs-vswitchd will be able to reconnect to controllers and
              process any new flow table modifications.

              Thus, with this option, the procedure for a  hot-upgrade  of  ovs-vswitchd  becomes
              roughly the following:

              1.  Stop ovs-vswitchd.

              2.  Set other_config:flow-restore-wait to true.

              3.  Start ovs-vswitchd.

              4.  Use  ovs-ofctl  (or  some  other  program,  such  as an OpenFlow controller) to
                  restore the OpenFlow flow table to the desired state.

              5.  Set other_config:flow-restore-wait to false (or remove  it  entirely  from  the
                  database).

              The  ovs-ctl’s ``restart’’ and ``force-reload-kmod’’ functions use the above config
              option during hot upgrades.

       other_config : flow-limit: optional string, containing an integer, at least 0
              The maximum number of flows allowed in the datapath flow table. Internally OVS will
              choose a flow limit which will likely be lower than this number, based on real time
              network conditions. Tweaking this value is discouraged unless you know exactly what
              you’re doing.

              The default is 200000.

       other_config : max-idle: optional string, containing an integer, at least 500
              The  maximum  time  (in  ms)  that  idle  flows will remain cached in the datapath.
              Internally OVS will check the validity and activity for  datapath  flows  regularly
              and  may  expire  flows  quicker  than  this  number,  based  on  real time network
              conditions. Tweaking this value is discouraged unless you know exactly what  you’re
              doing.

              The default is 10000.

       other_config : max-revalidator: optional string, containing an integer, at least 100
              The  maximum  time (in ms) that revalidator threads will wait before executing flow
              revalidation. Note that this is maximum allowed value. Actual timeout used  by  OVS
              is  minimum  of  max-idle  and  max-revalidator  values.  Tweaking  this  value  is
              discouraged unless you know exactly what you’re doing.

              The default is 500.

       other_config : min-revalidate-pps: optional string, containing an integer, at least 0
              Set minimum pps that flow must have in order to be  revalidated  when  revalidation
              duration exceeds half of max-revalidator config variable. Setting to 0 means always
              revalidate flows regardless of pps.

              The default is 5.

       other_config : offloaded-stats-delay: optional string, containing an integer, at least 0
              Set worst case delay (in ms) it might take before statistics of offloaded flows are
              updated.  Offloaded  flows  younger  than  this  delay  will  always be revalidated
              regardless of other_config:min-revalidate-pps.

              The default is 2000.

       other_config : hw-offload: optional string, either true or false
              Set this value to true to enable netdev flow offload.

              The default value is false. Changing this value requires restarting the daemon

              Currently Open vSwitch supports hardware offloading  on  Linux  systems.  On  other
              systems,  this  value  is ignored. This functionality is considered ’experimental’.
              Depending on which OpenFlow  matches  and  actions  are  configured,  which  kernel
              version  is  used,  and what hardware is available, Open vSwitch may not be able to
              offload functionality to hardware.

              In order to dump HW offloaded  flows  use  ovs-appctl  dpctl/dump-flows,  ovs-dpctl
              doesn’t support this functionality. See ovs-vswitchd(8) for details.

       other_config : n-offload-threads: optional string, containing an integer, in range 1 to 10
              Set this value to the number of threads created to manage hardware offloads.

              The default value is 1. Changing this value requires restarting the daemon.

              This is only relevant for userspace datapath and only if other_config:hw-offload is
              enabled.

       other_config : tc-policy: optional string, one of none, skip_hw, or skip_sw
              Specified the policy used with HW offloading. Options:

              none   Add software rule and offload rule to HW.

              skip_sw
                     Offload rule to HW only.

              skip_hw
                     Add software rule without offloading rule to HW.

              This is only relevant if other_config:hw-offload is enabled.

              The default value is none.

       other_config : dpdk-init: optional string, one of false, true, or try
              Set this value to true or try to enable runtime support for DPDK ports. The vswitch
              must have compile-time support for DPDK as well.

              A  value  of  true  will  cause the ovs-vswitchd process to abort if DPDK cannot be
              initialized. A value of try will allow the ovs-vswitchd process to continue running
              even if DPDK cannot be initialized.

              The default value is false. Changing this value requires restarting the daemon

              If  this  value  is  false  at  startup, any dpdk ports which are configured in the
              bridge will fail due to memory errors.

       other_config : dpdk-lcore-mask: optional string, containing an integer, at least 1
              Specifies the CPU cores where dpdk lcore threads should be spawned. The DPDK  lcore
              threads  are  used  for  DPDK  library  tasks,  such  as  library  internal message
              processing, logging, etc. Value should be in the form of a hex string (so  ’0x123’)
              similar to the ’taskset’ mask input.

              The  lowest  order  bit  corresponds  to  the  first  CPU core. A set bit means the
              corresponding core is available and an lcore thread will be created and  pinned  to
              it. If the input does not cover all cores, those uncovered cores are considered not
              set.

              For performance reasons, it is best to set this to a single  core  on  the  system,
              rather than allow lcore threads to float.

              If not specified, the value will be determined by choosing the lowest CPU core from
              initial cpu affinity list. Otherwise, the value will be passed directly to the DPDK
              library.

       other_config : pmd-cpu-mask: optional string
              Specifies  CPU mask for setting the cpu affinity of PMD (Poll Mode Driver) threads.
              Value should be in the form of hex string, similar to the dpdk  EAL  ’-c  COREMASK’
              option input or the ’taskset’ mask input.

              The  lowest  order  bit  corresponds  to  the  first  CPU core. A set bit means the
              corresponding core is available and a pmd thread will be created and pinned to  it.
              If  the  input  does  not cover all cores, those uncovered cores are considered not
              set.

              If not specified, one pmd thread will be created for each numa node and  pinned  to
              any available core on the numa node by default.

       other_config : dpdk-alloc-mem: optional string, containing an integer, at least 0
              Specifies the amount of memory to preallocate from the hugepage pool, regardless of
              socket. It is recommended that dpdk-socket-mem is used instead.

       other_config : dpdk-socket-mem: optional string
              Specifies the amount of memory to preallocate from the hugepage  pool,  on  a  per-
              socket basis.

              The  specifier  is a comma-separated string, in ascending order of CPU socket. E.g.
              On a four socket system 1024,0,2048 would  set  socket  0  to  preallocate  1024MB,
              socket  1 to preallocate 0MB, socket 2 to preallocate 2048MB and socket 3 (no value
              given) to preallocate 0MB.

              If other_config:dpdk-socket-mem and other_config:dpdk-alloc-mem are not  specified,
              neither  will  be  used and there will be no default value for each numa node. DPDK
              defaults   will   be   used   instead.    If    other_config:dpdk-socket-mem    and
              other_config:dpdk-alloc-mem  are  specified  at  the  same time, other_config:dpdk-
              socket-mem will be used as default. Changing this  value  requires  restarting  the
              daemon.

       other_config : dpdk-socket-limit: optional string
              Limits  the  maximum amount of memory that can be used from the hugepage pool, on a
              per-socket basis.

              The specifier is a comma-separated list of memory limits per socket. 0 will disable
              the limit for a particular socket.

              If  not  specified,  OVS  will not configure limits by default. Changing this value
              requires restarting the daemon.

       other_config : dpdk-hugepage-dir: optional string
              Specifies the path to the hugetlbfs mount point.

              If  not  specified,  this  will  be  guessed  by  the  DPDK  library  (default   is
              /dev/hugepages). Changing this value requires restarting the daemon.

       other_config : dpdk-extra: optional string
              Specifies additional eal command line arguments for DPDK.

              The default is empty. Changing this value requires restarting the daemon

       other_config : vhost-sock-dir: optional string
              Specifies  a  relative  path from external_ids:rundir to the vhost-user unix domain
              socket  files.  If  this  value  is  unset,  the  sockets  are  put   directly   in
              external_ids:rundir.

              Changing this value requires restarting the daemon.

       other_config : vhost-iommu-support: optional string, either true or false
              vHost  IOMMU  is a security feature, which restricts the vhost memory that a virtio
              device may access. vHost IOMMU support is disabled by default, due to a bug in QEMU
              implementations  of  the  vhost  REPLY_ACK  protocol, (on which vHost IOMMU relies)
              prior to v2.9.1. Setting this value to true enables vHost IOMMU support  for  vHost
              User Client ports in OvS-DPDK, starting from DPDK v17.11.

              Changing this value requires restarting the daemon.

       other_config : vhost-postcopy-support: optional string, either true or false
              vHost  post-copy  is a feature which allows switching live migration of VM attached
              to dpdkvhostuserclient port to post-copy mode if default pre-copy migration can not
              be  converged  or  takes  too  long to converge. Setting this value to true enables
              vHost post-copy support for all dpdkvhostuserclient ports. Available starting  from
              DPDK v18.11 and QEMU 2.12.

              Changing this value requires restarting the daemon.

       other_config : per-port-memory: optional string, either true or false
              By  default  OVS DPDK uses a shared memory model wherein devices that have the same
              MTU and socket values can share the  same  mempool.  Setting  this  value  to  true
              changes  this  behaviour.  Per port memory allow DPDK devices to use private memory
              per device. This can provide greater  transparency  as  regards  memory  usage  but
              potentially at the cost of greater memory requirements.

              Changing  this  value  requires restarting the daemon if dpdk-init has already been
              set to true.

       other_config : shared-mempool-config: optional string
              Specifies dpdk shared mempool config.

              Value should be set in the following form:

              other_config:shared-mempool-config=< user-shared-mempool-mtu-list>

              where

              •      <user-shared-mempool-mtu-list> ::= NULL | <non-empty-list>

              •      <non-empty-list> ::= <user-mtus> | <user-mtus> , <non-empty-list>

              •      <user-mtus> ::= <mtu-all-socket> | <mtu-socket-pair>

              •      <mtu-all-socket> ::= <mtu>

              •      <mtu-socket-pair> ::= <mtu> : <socket-id>

              Changing this value requires restarting the daemon if dpdk-init  has  already  been
              set to true.

       other_config  :  tx-flush-interval:  optional string, containing an integer, in range 0 to
       1,000,000
              Specifies the time in microseconds that a packet  can  wait  in  output  batch  for
              sending  i.e.  amount of time that packet can spend in an intermediate output queue
              before sending to netdev. This option can be  used  to  configure  balance  between
              throughput  and  latency. Lower values decreases latency while higher values may be
              useful to achieve higher performance.

              Defaults to 0 i.e. instant packet sending (latency optimized).

       other_config : pmd-perf-metrics: optional string, either true or false
              Enables recording of detailed PMD performance metrics  for  analysis  and  trouble-
              shooting. This can have a performance impact in the order of 1%.

              Defaults to false but can be changed at any time.

       other_config : smc-enable: optional string, either true or false
              Signature match cache or SMC is a cache between EMC and megaflow cache. It does not
              store the full key of the flow, so it is more memory  efficient  comparing  to  EMC
              cache. SMC is especially useful when flow count is larger than EMC capacity.

              Defaults to false but can be changed at any time.

       other_config : pmd-rxq-assign: optional string, one of cycles, group, or roundrobin
              Specifies how RX queues will be automatically assigned to CPU cores. Options:

              cycles Rxqs  will  be  sorted  by  order of measured processing cycles before being
                     assigned to CPU cores.

              roundrobin
                     Rxqs will be round-robined across CPU cores.

              group  Rxqs will be sorted by order of  measured  processing  cycles  before  being
                     assigned to CPU cores with lowest estimated load.

              The default value is cycles.

              Changing  this  value will affect an automatic re-assignment of Rxqs to CPUs. Note:
              Rxqs mapped to CPU cores with pmd-rxq-affinity are unaffected.

       other_config : pmd-rxq-isolate: optional string, either true or false
              Specifies if a CPU core will be isolated after being pinned with an Rx queue.

              Set this value to false to non-isolate a CPU core after it is pinned  with  an  Rxq
              using pmd-rxq-affinity. This will allow OVS to assign other Rxqs to that CPU core.

              The default value is true.

              This can only be false when pmd-rxq-assign is set to group.

       other_config : n-handler-threads: optional string, containing an integer, at least 1
              Attempts  to  specify  the  number  of  threads  for  software datapaths to use for
              handling new flows. Some datapaths may choose to ignore this and it will be set  to
              a sensible option for the datapath type.

              This  configuration  is  per  datapath. If you have more than one software datapath
              (e.g. some system bridges and some  netdev  bridges),  then  the  total  number  of
              threads is n-handler-threads times the number of software datapaths.

       other_config : n-revalidator-threads: optional string, containing an integer, at least 1
              Attempts  to  specify  the  number  of  threads  for  software datapaths to use for
              revalidating flows in the datapath. Some datapaths may choose to  ignore  this  and
              will set to a sensible option for the datapath type.

              Typically, there is a direct correlation between the number of revalidator threads,
              and the number of flows allowed in the datapath. The default is the number  of  cpu
              cores divided by four plus one. If n-handler-threads is set, the default changes to
              the number of cpu cores minus the number of handler threads.

              This configuration is per datapath. If you have more  than  one  software  datapath
              (e.g.  some  system  bridges  and  some  netdev  bridges), then the total number of
              threads is n-handler-threads times the number of software datapaths.

       other_config : emc-insert-inv-prob: optional string, containing an integer, in range 0  to
       4,294,967,295
              Specifies  the inverse probability (1/emc-insert-inv-prob) of a flow being inserted
              into the Exact Match Cache (EMC).  On  average  one  in  every  emc-insert-inv-prob
              packets  that  generate a unique flow will cause an insertion into the EMC. A value
              of 1 will result in an insertion for every flow (1/1 = 100%)  whereas  a  value  of
              zero will result in no insertions and essentially disable the EMC.

              Defaults to 100 ie. there is (1/100 =) 1% chance of EMC insertion.

       other_config : vlan-limit: optional string, containing an integer, at least 0
              Limits  the  number  of  VLAN  headers that can be matched to the specified number.
              Further VLAN headers will be treated as payload, e.g. a  packet  with  more  802.1q
              headers will match Ethernet type 0x8100.

              Open  vSwitch  userspace  currently supports at most 2 VLANs, and each datapath has
              its own limit. If vlan-limit is nonzero, it acts as a further limit.

              If this value is absent, the  default  is  currently  1.  This  maintains  backward
              compatibility  with  controllers  that  were  designed  for  use  with Open vSwitch
              versions earlier than 2.8, which only supported one VLAN.

       other_config : bundle-idle-timeout: optional string, containing an integer, at least 1
              The maximum time (in seconds) that idle bundles will wait to be  expired  since  it
              was either opened, modified or closed.

              OpenFlow  specification mandates the timeout to be at least one second. The default
              is 10 seconds.

       other_config : offload-rebalance: optional string, either true or false
              Configures HW offload rebalancing, that  allows  to  dynamically  offload  and  un-
              offload flows while an offload-device is out of resources (OOR). This policy allows
              flows to be selected for offloading based on the packets-per-second (pps)  rate  of
              flows.

              Set this value to true to enable this option.

              The default value is false. Changing this value requires restarting the daemon.

              This is only relevant if HW offloading is enabled (hw-offload). When this policy is
              enabled, it also requires ’tc-policy’ to be set to ’skip_sw’.

       other_config : pmd-auto-lb: optional string, either true or false
              Configures PMD Auto Load Balancing that allows automatic assignment of RX queues to
              PMDs  if  any  of  PMDs is overloaded (i.e. a processing cycles > other_config:pmd-
              auto-lb-load-threshold).

              It uses current scheme of  cycle  based  assignment  of  RX  queues  that  are  not
              statically pinned to PMDs.

              The default value is false.

              Set  this  value to true to enable this option. It is currently disabled by default
              and an experimental feature.

              This only comes in effect if cycle based assignment is enabled and there  are  more
              than  one  non-isolated  PMDs  present  and  at least one of it polls more than one
              queue.

       other_config : pmd-auto-lb-rebal-interval: optional  string,  containing  an  integer,  in
       range 0 to 20,000
              The minimum time (in minutes) 2 consecutive PMD Auto Load Balancing iterations.

              The  default  value  is  1  min.  If  configured to 0 then it would be converted to
              default value i.e. 1 min

              This option can be configured to avoid frequent trigger of auto load  balancing  of
              PMDs.  For  e.g.  set the value (in min) such that it occurs once in few hours or a
              day or a week.

       other_config : pmd-auto-lb-load-threshold: optional  string,  containing  an  integer,  in
       range 0 to 100
              Specifies  the  minimum  PMD  thread  load threshold (% of used cycles) of any non-
              isolated PMD threads when a PMD Auto Load Balance may be triggered.

              The default value is 95%.

       other_config : pmd-auto-lb-improvement-threshold: optional string, containing an  integer,
       in range 0 to 100
              Specifies  the minimum evaluated % improvement in load distribution across the non-
              isolated PMD threads that will allow a PMD Auto Load Balance to occur.

              Note, setting this parameter to 0 will always allow an auto load balance  to  occur
              regardless of estimated improvement or not.

              The default value is 25%.

       other_config : pmd-sleep-max: optional string, containing an integer, in range 0 to 10,000
              Specifies  the  maximum  sleep  time  that  will  be  requested in microseconds per
              iteration for a PMD thread which has received zero or a  small  amount  of  packets
              from the Rx queues it is polling.

              The  actual sleep time requested is based on the load of the Rx queues that the PMD
              polls and may be less than the maximum value.

              The default value is 0 microseconds, which  means  that  the  PMD  will  not  sleep
              regardless of the load from the Rx queues that it polls.

              The maximum value is 10000 microseconds.

       other_config : userspace-tso-enable: optional string, either true or false
              Set  this value to true to enable userspace support for TCP Segmentation Offloading
              (TSO). When it is enabled, the interfaces can provide an oversized TCP  segment  to
              the  datapath  and  the  datapath  will  offload  the TCP segmentation and checksum
              calculation to the interfaces when necessary.

              The default value is false. Changing this value requires restarting the daemon.

              The feature only works if Open vSwitch is built with DPDK support.

              The feature is considered experimental.

     Status:

       next_cfg: integer
              Sequence number for client to increment. When a client modifies  any  part  of  the
              database  configuration  and wishes to wait for Open vSwitch to finish applying the
              changes, it may increment this sequence number.

       cur_cfg: integer
              Sequence number that Open vSwitch sets to the current value of  next_cfg  after  it
              finishes applying a set of configuration changes.

       dpdk_initialized: boolean
              True  if other_config:dpdk-init is set to true and the DPDK library is successfully
              initialized.

     Statistics:

       The statistics column contains key-value pairs  that  report  statistics  about  a  system
       running an Open vSwitch. These are updated periodically (currently, every 5 seconds). Key-
       value pairs that cannot be determined or that do not apply to a platform are omitted.

       other_config : enable-statistics: optional string, either true or false
              Statistics are disabled by default to  avoid  overhead  in  the  common  case  when
              statistics gathering is not useful. Set this value to true to enable populating the
              statistics column or to false to explicitly disable it.

       statistics : cpu: optional string, containing an integer, at least 1
              Number of CPU processors, threads, or cores currently online and available  to  the
              operating  system on which Open vSwitch is running, as an integer. This may be less
              than the number installed, if some are not online or if they are not  available  to
              the operating system.

              Open  vSwitch userspace processes are not multithreaded, but the Linux kernel-based
              datapath is.

       statistics : load_average: optional string
              A comma-separated list of three floating-point  numbers,  representing  the  system
              load average over the last 1, 5, and 15 minutes, respectively.

       statistics : memory: optional string
              A  comma-separated  list of integers, each of which represents a quantity of memory
              in kilobytes that describes the operating system on which Open vSwitch is  running.
              In respective order, these values are:

              1.  Total amount of RAM allocated to the OS.

              2.  RAM allocated to the OS that is in use.

              3.  RAM  that  can  be  flushed out to disk or otherwise discarded if that space is
                  needed for another purpose. This number is necessarily less than  or  equal  to
                  the previous value.

              4.  Total disk space allocated for swap.

              5.  Swap space currently in use.

              On  Linux,  all  five values can be determined and are included. On other operating
              systems, only the first two values can be determined, so the list  will  only  have
              two values.

       statistics : process_NAME: optional string
              One  such key-value pair, with NAME replaced by a process name, will exist for each
              running Open vSwitch daemon process, with name replaced by the daemon’s name  (e.g.
              process_ovs-vswitchd).  The  value  is  a  comma-separated  list  of  integers. The
              integers represent the following, with memory measured in kilobytes  and  durations
              in milliseconds:

              1.  The process’s virtual memory size.

              2.  The process’s resident set size.

              3.  The amount of user and system CPU time consumed by the process.

              4.  The  number  of  times  that  the  process  has  crashed and been automatically
                  restarted by the monitor.

              5.  The duration since the process was started.

              6.  The duration for which the process has been running.

              The interpretation of some of these values  depends  on  whether  the  process  was
              started  with  the  --monitor. If it was not, then the crash count will always be 0
              and the two durations will always be the same. If --monitor  was  given,  then  the
              crash  count  may  be positive; if it is, the latter duration is the amount of time
              since the most recent crash and restart.

              There will be one key-value pair for each file in Open vSwitch’s ``run  directory’’
              (usually  /var/run/openvswitch)  whose  name  ends  in  .pid,  whose contents are a
              process ID, and which is locked by a running process. The name is  taken  from  the
              pidfile’s name.

              Currently  Open  vSwitch  is  only  able to obtain all of the above detail on Linux
              systems. On other systems, the same key-value pairs will be present but the  values
              will always be the empty string.

       statistics : file_systems: optional string
              A space-separated list of information on local, writable file systems. Each item in
              the list describes one file system and consists in turn of a  comma-separated  list
              of the following:

              1.  Mount  point,  e.g.  / or /var/log. Any spaces or commas in the mount point are
                  replaced by underscores.

              2.  Total size, in kilobytes, as an integer.

              3.  Amount of storage in use, in kilobytes, as an integer.

              This key-value pair is omitted if there are no local, writable file systems  or  if
              Open vSwitch cannot obtain the needed information.

     Version Reporting:

       These  columns  report  the  types  and versions of the hardware and software running Open
       vSwitch. We recommend in general that software should test whether specific  features  are
       supported instead of relying on version number checks. These values are primarily intended
       for reporting to human administrators.

       ovs_version: optional string
              The Open vSwitch version number, e.g. 1.1.0.

       db_version: optional string
              The  database  schema  version  number,  e.g.  1.2.3.  See  ovsdb-tool(1)  for   an
              explanation of the numbering scheme.

              The  schema  version is part of the database schema, so it can also be retrieved by
              fetching the schema using the Open vSwitch database protocol.

       system_type: optional string
              An identifier for the type of system on top of which Open vSwitch runs, e.g. KVM.

              System integrators are responsible for choosing and setting  an  appropriate  value
              for this column.

       system_version: optional string
              The  version of the system identified by system_type, e.g. 4.18.0-372.19.1.el8_6 on
              RHEL 8.6 with kernel 4.18.0-372.19.1.

              System integrators are responsible for choosing and setting  an  appropriate  value
              for this column.

       dpdk_version: optional string
              The version of the linked DPDK library.

     Capabilities:

       These columns report capabilities of the Open vSwitch instance.

       datapath_types: set of strings
              This  column  reports the different dpifs registered with the system. These are the
              values that this instance supports in the datapath_type column of the Bridge table.

       iface_types: set of strings
              This column reports the different netdevs registered with the system. These are the
              values that this instance supports in the type column of the Interface table.

     Database Configuration:

       These  columns  primarily configure the Open vSwitch database (ovsdb-server), not the Open
       vSwitch switch (ovs-vswitchd). The OVSDB database also uses the ssl settings.

       The Open vSwitch switch does read  the  database  configuration  to  determine  remote  IP
       addresses to which in-band control should apply.

       manager_options: set of Managers
              Database  clients  to  which  the Open vSwitch database server should connect or to
              which it should listen, along with options for  how  these  connections  should  be
              configured. See the Manager table for more information.

              For  this column to serve its purpose, ovsdb-server must be configured to honor it.
              The  easiest  way  to  do  this  is  to  invoke  ovsdb-server   with   the   option
              --remote=db:Open_vSwitch,Open_vSwitch,manager_options   The  startup  scripts  that
              accompany Open vSwitch do this by default.

     IPsec:

       These settings control the global configuration of IPsec tunnels. The  options  column  of
       the  Interface  table  configures  IPsec  for  individual tunnels. The options column also
       allows for custom options prefixed with ipsec_ to be passed to the individual connections.

       OVS IPsec supports the following three  forms  of  authentication.  Currently,  all  IPsec
       tunnels must use the same form:

              1.  Pre-shared keys: Omit the global settings. On each tunnel, set options:psk.

              2.  Self-signed  certificates: Set the private_key and certificate global settings.
                  On each tunnel, set options:remote_cert. The remote certificate  can  be  self-
                  signed.

              3.  CA-signed  certificates:  Set  all  of the global settings. On each tunnel, set
                  options:remote_name to the common name (CN)  of  the  remote  certificate.  The
                  remote certificate must be signed by the CA.

       other_config : private_key: optional string
              Name  of  a  PEM  file containing the private key used as the switch’s identity for
              IPsec tunnels.

       other_config : certificate: optional string
              Name of a PEM file containing a certificate that  certifies  the  switch’s  private
              key, and identifies a trustworthy switch for IPsec tunnels. The certificate must be
              x.509 version 3 and with the string in common name (CN) also  set  in  the  subject
              alternative name (SAN).

       other_config : ca_cert: optional string
              Name  of  a  PEM  file  containing  the CA certificate used to verify that a remote
              switch of the IPsec tunnel is trustworthy.

     Plaintext Tunnel Policy:

       When an IPsec tunnel is configured in this database, multiple independent components  take
       responsibility for implementing it. ovs-vswitchd and its datapath handle packet forwarding
       to the tunnel and a separate daemon pushes the tunnel’s IPsec policy configuration to  the
       kernel  or  other  entity that implements it. There is a race: if the former configuration
       completes before the latter, then packets sent by the local host over the  tunnel  can  be
       transmitted  in  plaintext.  Using  this  setting,  OVS  users  can avoid this undesirable
       situation.

       other_config : ipsec_skb_mark: optional string
              This setting takes the form value/mask. If it is specified, then the skb_mark field
              in  every outgoing tunneled packet sent in plaintext is compared against it and, if
              it matches, the packet is dropped. This is a global  setting  that  is  applied  to
              every  tunneled  packet,  regardless of whether IPsec encryption is enabled for the
              tunnel, the type of tunnel, or whether OVS is involved.

              Example policies:

              1/1    Drop all unencrypted tunneled packets in which the least-significant bit  of
                     skb_mark  is  1.  This would be a useful policy given an OpenFlow flow table
                     that sets skb_mark to 1 for traffic that should be  encrypted.  The  default
                     skb_mark is 0, so this would not affect other traffic.

              0/1    Drop  all unencrypted tunneled packets in which the least-significant bit of
                     skb_mark is 0. This would be a useful  policy  if  no  unencrypted  tunneled
                     traffic  should exit the system without being specially permitted by setting
                     skb_mark to 1.

              (empty)
                     If this setting is empty or unset, then all unencrypted tunneled packets are
                     transmitted in the usual way.

     Common Columns:

       The overall purpose of these columns is described under Common Columns at the beginning of
       this document.

       other_config: map of string-string pairs

       external_ids: map of string-string pairs

Bridge TABLE

       Configuration for a bridge within an Open_vSwitch.

       A Bridge record represents an Ethernet switch with one or more ``ports,’’  which  are  the
       Port records pointed to by the Bridge’s ports column.

   Summary:
       Core Features:
         name                        immutable string (must be unique within table)
         ports                       set of Ports
         mirrors                     set of Mirrors
         netflow                     optional NetFlow
         sflow                       optional sFlow
         ipfix                       optional IPFIX
         flood_vlans                 set of up to 4,096 integers, in range 0 to 4,095
         auto_attach                 optional AutoAttach
       OpenFlow Configuration:
         controller                  set of Controllers
         flow_tables                 map of integer-Flow_Table pairs, key in range 0 to 254
         fail_mode                   optional string, either secure or standalone
         datapath_id                 optional string
         datapath_version            string
         other_config : datapath-id  optional string
         other_config : dp-desc      optional string
         other_config : dp-sn        optional string
         other_config : disable-in-band
                                     optional string, either true or false
         other_config : in-band-queue
                                     optional  string,  containing  an  integer,  in  range  0 to
                                     4,294,967,295
         other_config : controller-queue-size
                                     optional string, containing an integer, in range 1 to 512
         protocols                   set of strings, one of OpenFlow10,  OpenFlow11,  OpenFlow12,
                                     OpenFlow13, OpenFlow14, or OpenFlow15
       Spanning Tree Configuration:
         STP Configuration:
            stp_enable               boolean
            other_config : stp-system-id
                                     optional string
            other_config : stp-priority
                                     optional string, containing an integer, in range 0 to 65,535
            other_config : stp-hello-time
                                     optional string, containing an integer, in range 1 to 10
            other_config : stp-max-age
                                     optional string, containing an integer, in range 6 to 40
            other_config : stp-forward-delay
                                     optional string, containing an integer, in range 4 to 30
            other_config : mcast-snooping-aging-time
                                     optional string, containing an integer, at least 1
            other_config : mcast-snooping-table-size
                                     optional string, containing an integer, at least 1
            other_config : mcast-snooping-disable-flood-unregistered
                                     optional string, either true or false
         STP Status:
            status : stp_bridge_id   optional string
            status : stp_designated_root
                                     optional string
            status : stp_root_path_cost
                                     optional string
       Rapid Spanning Tree:
         RSTP Configuration:
            rstp_enable              boolean
            other_config : rstp-address
                                     optional string
            other_config : rstp-priority
                                     optional string, containing an integer, in range 0 to 61,440
            other_config : rstp-ageing-time
                                     optional  string,  containing  an  integer,  in  range 10 to
                                     1,000,000
            other_config : rstp-force-protocol-version
                                     optional string, containing an integer
            other_config : rstp-max-age
                                     optional string, containing an integer, in range 6 to 40
            other_config : rstp-forward-delay
                                     optional string, containing an integer, in range 4 to 30
            other_config : rstp-transmit-hold-count
                                     optional string, containing an integer, in range 1 to 10
         RSTP Status:
            rstp_status : rstp_bridge_id
                                     optional string
            rstp_status : rstp_root_id
                                     optional string
            rstp_status : rstp_root_path_cost
                                     optional string, containing an integer, at least 0
            rstp_status : rstp_designated_id
                                     optional string
            rstp_status : rstp_designated_port_id
                                     optional string
            rstp_status : rstp_bridge_port_id
                                     optional string
       Multicast Snooping Configuration:
         mcast_snooping_enable       boolean
       Other Features:
         datapath_type               string
         external_ids : bridge-id    optional string
         other_config : hwaddr       optional string
         other_config : forward-bpdu
                                     optional string, either true or false
         other_config : mac-aging-time
                                     optional string, containing an integer, at least 1
         other_config : mac-table-size
                                     optional string, containing an integer, at least 1
       Common Columns:
         other_config                map of string-string pairs
         external_ids                map of string-string pairs

   Details:
     Core Features:

       name: immutable string (must be unique within table)
              Bridge identifier. Must be unique among the names of ports, interfaces, and bridges
              on a host.

              The name must be alphanumeric and must not contain forward or backward slashes. The
              name of a bridge is also the name of an Interface (and a Port) within  the  bridge,
              so  the  restrictions  on  the  name column in the Interface table, particularly on
              length, also apply to bridge names. Refer to the documentation for Interface  names
              for details.

       ports: set of Ports
              Ports included in the bridge.

       mirrors: set of Mirrors
              Port mirroring configuration.

       netflow: optional NetFlow
              NetFlow configuration.

       sflow: optional sFlow
              sFlow(R) configuration.

       ipfix: optional IPFIX
              IPFIX configuration.

       flood_vlans: set of up to 4,096 integers, in range 0 to 4,095
              VLAN IDs of VLANs on which MAC address learning should be disabled, so that packets
              are flooded instead of being sent to specific ports that are  believed  to  contain
              packets’  destination  MACs. This should ordinarily be used to disable MAC learning
              on VLANs used for mirroring (RSPAN VLANs). It may also be useful for debugging.

              SLB bonding (see the bond_mode column in  the  Port  table)  is  incompatible  with
              flood_vlans.  Consider  using  another  bonding  mode or a different type of mirror
              instead.

       auto_attach: optional AutoAttach
              Auto Attach configuration.

     OpenFlow Configuration:

       controller: set of Controllers
              OpenFlow controller set. If unset, then no OpenFlow controllers will be used.

              If there are primary controllers, removing all of them  clears  the  OpenFlow  flow
              tables,  group  table, and meter table. If there are no primary controllers, adding
              one also clears these tables. Other changes to the  set  of  controllers,  such  as
              adding  or  removing  a  service  controller,  adding another primary controller to
              supplement an existing primary controller, or removing  only  one  of  two  primary
              controllers, have no effect on these tables.

       flow_tables: map of integer-Flow_Table pairs, key in range 0 to 254
              Configuration  for  OpenFlow  tables.  Each  pair maps from an OpenFlow table ID to
              configuration for that table.

       fail_mode: optional string, either secure or standalone
              When a controller is configured, it is, ordinarily, responsible for setting up  all
              flows  on  the  switch.  Thus,  if  the  connection to the controller fails, no new
              network connections can be set up. If the connection to the controller  stays  down
              long enough, no packets can pass through the switch at all. This setting determines
              the switch’s response to such a situation. It may be set to one of the following:

              standalone
                     If no message is received from the controller for three times the inactivity
                     probe  interval  (see  inactivity_probe),  then  Open vSwitch will take over
                     responsibility for setting up flows. In this mode, Open vSwitch  causes  the
                     bridge  to  act  like  an  ordinary  MAC-learning  switch. Open vSwitch will
                     continue to retry connecting to the controller in the background  and,  when
                     the connection succeeds, it will discontinue its standalone behavior.

              secure Open vSwitch will not set up flows on its own when the controller connection
                     fails or when no controllers are defined. The bridge will continue to  retry
                     connecting to any defined controllers forever.

              The  default  is  standalone  if  the  value  is unset, but future versions of Open
              vSwitch may change the default.

              The standalone mode can create forwarding loops on a bridge that has more than  one
              uplink  port  unless  STP  is  enabled.  To avoid loops on such a bridge, configure
              secure mode or enable STP (see stp_enable).

              The fail_mode setting applies only to  primary  controllers.  When  more  than  one
              primary  controller  is  configured,  fail_mode is considered only when none of the
              configured controllers can be contacted.

              Changing fail_mode when no primary controllers are configured clears  the  OpenFlow
              flow tables, group table, and meter table.

       datapath_id: optional string
              Reports  the  OpenFlow  datapath  ID  in  use. Exactly 16 hex digits. (Setting this
              column has no useful effect. Set other-config:datapath-id instead.)

       datapath_version: string
              Reports  the  datapath  version.  This   column   is   maintained   for   backwards
              compatibility.  The  preferred locatation is the datapath_id column of the Datapath
              table. The full documentation for this column is there.

       other_config : datapath-id: optional string
              Overrides the default OpenFlow datapath ID,  setting  it  to  the  specified  value
              specified  in  hex.  The  value  must  either have a 0x prefix or be exactly 16 hex
              digits long. May not be all-zero.

       other_config : dp-desc: optional string
              Human readable description of datapath. It is a  maximum  256  byte-long  free-form
              string  to describe the datapath for debugging purposes, e.g. switch3 in room 3120.
              The value is returned by the switch as  a  part  of  reply  to  OFPMP_DESC  request
              (ofp_desc).   The  OpenFlow  specification  (e.g.  1.3.5)  describes  the  ofp_desc
              structure to contaion  "NULL  terminated  ASCII  strings".  For  the  compatibility
              reasons no more than 255 ASCII characters should be used.

       other_config : dp-sn: optional string
              Serial  number.  It  is  a  maximum  32  byte-long  free-form  string to provide an
              additional switch identification. The value is returned by the switch as a part  of
              reply  to  OFPMP_DESC  request  (ofp_desc). Same as mentioned in the description of
              other-config:dp-desc, the string should be no more than 31 ASCII characters for the
              compatibility.

       other_config : disable-in-band: optional string, either true or false
              If  set to true, disable in-band control on the bridge regardless of controller and
              manager settings.

       other_config : in-band-queue: optional string,  containing  an  integer,  in  range  0  to
       4,294,967,295
              A  queue  ID as a nonnegative integer. This sets the OpenFlow queue ID that will be
              used by flows set up by in-band control on this bridge. If unset, or  if  the  port
              used  by  an in-band control flow does not have QoS configured, or if the port does
              not have a queue with the specified ID, the default queue is used instead.

       other_config : controller-queue-size: optional string, containing an integer, in  range  1
       to 512
              This  sets  the  maximum  size  of the queue of packets that need to be sent to the
              OpenFlow management controller. The value must be less than 512. If  not  specified
              the  queue  size  is  limited to 100 packets by default. Note: increasing the queue
              size might have a negative impact on latency.

       protocols:  set  of  strings,  one  of  OpenFlow10,  OpenFlow11,  OpenFlow12,  OpenFlow13,
       OpenFlow14, or OpenFlow15
              List  of  OpenFlow  protocols that may be used when negotiating a connection with a
              controller. OpenFlow 1.0, 1.1, 1.2, 1.3, 1.4, and 1.5 are  enabled  by  default  if
              this column is empty.

     Spanning Tree Configuration:

       The  IEEE 802.1D Spanning Tree Protocol (STP) is a network protocol that ensures loop-free
       topologies. It allows redundant links to be included in the network to  provide  automatic
       backup paths if the active links fails.

       These  settings  configure  the  slower-to-converge  but still widely supported version of
       Spanning Tree Protocol, sometimes known as 802.1D-1998. Open  vSwitch  also  supports  the
       newer  Rapid  Spanning  Tree Protocol (RSTP), documented later in the section titled Rapid
       Spanning Tree Configuration.

     STP Configuration:

       stp_enable: boolean
              Enable spanning tree on the bridge. By default, STP is disabled on  bridges.  Bond,
              internal,  and  mirror  ports  are  not  supported  and will not participate in the
              spanning tree.

              STP and RSTP are mutually exclusive. If both are enabled, RSTP will be used.

       other_config : stp-system-id: optional string
              The bridge’s STP identifier (the lower 48  bits  of  the  bridge-id)  in  the  form
              xx:xx:xx:xx:xx:xx. By default, the identifier is the MAC address of the bridge.

       other_config : stp-priority: optional string, containing an integer, in range 0 to 65,535
              The  bridge’s relative priority value for determining the root bridge (the upper 16
              bits of the bridge-id). A bridge with the lowest bridge-id is elected the root.  By
              default, the priority is 0x8000.

       other_config : stp-hello-time: optional string, containing an integer, in range 1 to 10
              The  interval  between  transmissions  of  hello  messages  by designated ports, in
              seconds. By default the hello interval is 2 seconds.

       other_config : stp-max-age: optional string, containing an integer, in range 6 to 40
              The maximum age of the information transmitted by the bridge when it  is  the  root
              bridge, in seconds. By default, the maximum age is 20 seconds.

       other_config : stp-forward-delay: optional string, containing an integer, in range 4 to 30
              The delay to wait between transitioning root and designated ports to forwarding, in
              seconds. By default, the forwarding delay is 15 seconds.

       other_config : mcast-snooping-aging-time: optional string, containing an integer, at least
       1
              The  maximum  number  of  seconds to retain a multicast snooping entry for which no
              packets have been seen. The default is  currently  300  seconds  (5  minutes).  The
              value,  if  specified,  is  forced  into  a  reasonable range, currently 15 to 3600
              seconds.

       other_config : mcast-snooping-table-size: optional string, containing an integer, at least
       1
              The  maximum  number  of  multicast  snooping  addresses  to  learn. The default is
              currently 2048. The value,  if  specified,  is  forced  into  a  reasonable  range,
              currently 10 to 1,000,000.

       other_config  : mcast-snooping-disable-flood-unregistered: optional string, either true or
       false
              If set to false, unregistered multicast packets are forwarded to all ports. If  set
              to  true,  unregistered  multicast  packets  are  forwarded  to  ports connected to
              multicast routers.

     STP Status:

       These key-value pairs report the status of 802.1D-1998. They are present only  if  STP  is
       enabled (via the stp_enable column).

       status : stp_bridge_id: optional string
              The  bridge  ID used in spanning tree advertisements, in the form xxxx.yyyyyyyyyyyy
              where the xs are the STP priority, the ys are the STP system ID, and each x  and  y
              is a hex digit.

       status : stp_designated_root: optional string
              The   designated   root   for   this   spanning   tree,   in   the   same  form  as
              status:stp_bridge_id. If this bridge is the root, this will have the same value  as
              status:stp_bridge_id, otherwise it will differ.

       status : stp_root_path_cost: optional string
              The  path  cost  of  reaching  the designated bridge. A lower number is better. The
              value is 0 if this bridge is the root, otherwise it is higher.

     Rapid Spanning Tree:

       Rapid Spanning Tree Protocol (RSTP), like STP, is a network protocol  that  ensures  loop-
       free topologies. RSTP superseded STP with the publication of 802.1D-2004. Compared to STP,
       RSTP converges more quickly and recovers more quickly from failures.

     RSTP Configuration:

       rstp_enable: boolean
              Enable Rapid Spanning Tree on the bridge. By default, RSTP is disabled on  bridges.
              Bond,  internal, and mirror ports are not supported and will not participate in the
              spanning tree.

              STP and RSTP are mutually exclusive. If both are enabled, RSTP will be used.

       other_config : rstp-address: optional string
              The bridge’s RSTP address (the  lower  48  bits  of  the  bridge-id)  in  the  form
              xx:xx:xx:xx:xx:xx. By default, the address is the MAC address of the bridge.

       other_config : rstp-priority: optional string, containing an integer, in range 0 to 61,440
              The  bridge’s relative priority value for determining the root bridge (the upper 16
              bits of the bridge-id). A bridge with the lowest bridge-id is elected the root.  By
              default, the priority is 0x8000 (32768). This value needs to be a multiple of 4096,
              otherwise it’s rounded to the nearest inferior one.

       other_config : rstp-ageing-time: optional string, containing an integer, in  range  10  to
       1,000,000
              The Ageing Time parameter for the Bridge. The default value is 300 seconds.

       other_config : rstp-force-protocol-version: optional string, containing an integer
              The Force Protocol Version parameter for the Bridge. This can take the value 0 (STP
              Compatibility mode) or 2 (the default, normal operation).

       other_config : rstp-max-age: optional string, containing an integer, in range 6 to 40
              The maximum age of the information transmitted by the Bridge when it  is  the  Root
              Bridge. The default value is 20.

       other_config  :  rstp-forward-delay: optional string, containing an integer, in range 4 to
       30
              The delay  used  by  STP  Bridges  to  transition  Root  and  Designated  Ports  to
              Forwarding. The default value is 15.

       other_config  : rstp-transmit-hold-count: optional string, containing an integer, in range
       1 to 10
              The Transmit  Hold  Count  used  by  the  Port  Transmit  state  machine  to  limit
              transmission rate. The default value is 6.

     RSTP Status:

       These  key-value  pairs report the status of 802.1D-2004. They are present only if RSTP is
       enabled (via the rstp_enable column).

       rstp_status : rstp_bridge_id: optional string
              The  bridge  ID  used  in  rapid  spanning  tree  advertisements,   in   the   form
              x.yyy.zzzzzzzzzzzz  where  x  is  the  RSTP priority, the ys are a locally assigned
              system ID extension, the zs are the STP system ID, and each x, y, or  z  is  a  hex
              digit.

       rstp_status : rstp_root_id: optional string
              The  root of this spanning tree, in the same form as rstp_status:rstp_bridge_id. If
              this   bridge   is   the   root,   this   will   have    the    same    value    as
              rstp_status:rstp_bridge_id, otherwise it will differ.

       rstp_status : rstp_root_path_cost: optional string, containing an integer, at least 0
              The  path  cost  of  reaching the root. A lower number is better. The value is 0 if
              this bridge is the root, otherwise it is higher.

       rstp_status : rstp_designated_id: optional string
              The RSTP designated ID, in the same form as rstp_status:rstp_bridge_id.

       rstp_status : rstp_designated_port_id: optional string
              The RSTP designated port ID, as a 4-digit hex number.

       rstp_status : rstp_bridge_port_id: optional string
              The RSTP bridge port ID, as a 4-digit hex number.

     Multicast Snooping Configuration:

       Multicast snooping (RFC 4541) monitors the Internet Group Management Protocol  (IGMP)  and
       Multicast  Listener Discovery traffic between hosts and multicast routers. The switch uses
       what IGMP and MLD snooping learns to forward multicast traffic only to interfaces that are
       connected to interested receivers. Currently it supports IGMPv1, IGMPv2, IGMPv3, MLDv1 and
       MLDv2 protocols.

       mcast_snooping_enable: boolean
              Enable multicast snooping on the bridge. For now, the default is disabled.

     Other Features:

       datapath_type: string
              Name of datapath provider. The kernel  datapath  has  type  system.  The  userspace
              datapath  has  type netdev. A manager may refer to the datapath_types column of the
              Open_vSwitch table for a list of the types accepted by this Open vSwitch instance.

       external_ids : bridge-id: optional string
              A unique identifier of the bridge.

       other_config : hwaddr: optional string
              An Ethernet address in the form xx:xx:xx:xx:xx:xx to set the  hardware  address  of
              the local port and influence the datapath ID.

       other_config : forward-bpdu: optional string, either true or false
              Controls forwarding of BPDUs and other network control frames when NORMAL action is
              invoked. When this  option  is  false  or  unset,  frames  with  reserved  Ethernet
              addresses  (see  table below) will not be forwarded. When this option is true, such
              frames will not be treated specially.

              The above general rule has the following exceptions:

              •      If STP is enabled on the bridge (see the stp_enable  column  in  the  Bridge
                     table),  the bridge processes all received STP packets and never passes them
                     to OpenFlow or forwards them. This is true even if STP  is  disabled  on  an
                     individual port.

              •      If  LLDP  is  enabled  on an interface (see the lldp column in the Interface
                     table), the interface processes received LLDP packets and never passes  them
                     to OpenFlow or forwards them.

              Set  this  option  to  true  if the Open vSwitch bridge connects different Ethernet
              networks and is not configured to participate in STP.

              This option affects packets with the following destination MAC addresses:

              01:80:c2:00:00:00
                     IEEE 802.1D Spanning Tree Protocol (STP).

              01:80:c2:00:00:01
                     IEEE Pause frame.

              01:80:c2:00:00:0x
                     Other reserved protocols.

              00:e0:2b:00:00:00
                     Extreme Discovery Protocol (EDP).

              00:e0:2b:00:00:04 and 00:e0:2b:00:00:06
                     Ethernet Automatic Protection Switching (EAPS).

              01:00:0c:cc:cc:cc
                     Cisco Discovery  Protocol  (CDP),  VLAN  Trunking  Protocol  (VTP),  Dynamic
                     Trunking Protocol (DTP), Port Aggregation Protocol (PAgP), and others.

              01:00:0c:cc:cc:cd
                     Cisco Shared Spanning Tree Protocol PVSTP+.

              01:00:0c:cd:cd:cd
                     Cisco STP Uplink Fast.

              01:00:0c:00:00:00
                     Cisco Inter Switch Link.

              01:00:0c:cc:cc:cx
                     Cisco CFM.

       other_config : mac-aging-time: optional string, containing an integer, at least 1
              The  maximum  number of seconds to retain a MAC learning entry for which no packets
              have been seen. The default is currently 300 seconds (5  minutes).  The  value,  if
              specified, is forced into a reasonable range, currently 15 to 3600 seconds.

              A  short  MAC  aging time allows a network to more quickly detect that a host is no
              longer connected to a switch port. However, it  also  makes  it  more  likely  that
              packets  will be flooded unnecessarily, when they are addressed to a connected host
              that rarely transmits packets. To reduce the incidence of unnecessary flooding, use
              a  MAC  aging time longer than the maximum interval at which a host will ordinarily
              transmit packets.

       other_config : mac-table-size: optional string, containing an integer, at least 1
              The maximum number of MAC addresses to learn. The default is  currently  8192.  The
              value, if specified, is forced into a reasonable range, currently 10 to 1,000,000.

     Common Columns:

       The overall purpose of these columns is described under Common Columns at the beginning of
       this document.

       other_config: map of string-string pairs

       external_ids: map of string-string pairs

Port TABLE

       A port within a Bridge.

       Most commonly, a port has exactly one ``interface,’’ pointed to by its interfaces  column.
       Such  a  port  logically  corresponds to a port on a physical Ethernet switch. A port with
       more than one interface is a ``bonded port’’ (see Bonding Configuration).

       Some properties that one might think as belonging to a  port  are  actually  part  of  the
       port’s Interface members.

   Summary:
       name                          immutable string (must be unique within table)
       interfaces                    set of 1 or more Interfaces
       VLAN Configuration:
         vlan_mode                   optional string, one of access, dot1q-tunnel, native-tagged,
                                     native-untagged, or trunk
         tag                         optional integer, in range 0 to 4,095
         trunks                      set of up to 4,096 integers, in range 0 to 4,095
         cvlans                      set of up to 4,096 integers, in range 0 to 4,095
         other_config : qinq-ethtype
                                     optional string, either 802.1ad or 802.1q
         other_config : priority-tags
                                     optional string, one of always, if-nonzero, or never
       Bonding Configuration:
         bond_mode                   optional  string,  one  of  active-backup,  balance-slb,  or
                                     balance-tcp
         other_config : bond-hash-basis
                                     optional string, containing an integer
         other_config : lb-output-action
                                     optional string, either true or false
         other_config : bond-primary
                                     optional string
         other_config : all-members-active
                                     optional string, either true or false
         Link Failure Detection:
            other_config : bond-detect-mode
                                     optional string, either carrier or miimon
            other_config : bond-miimon-interval
                                     optional string, containing an integer
            bond_updelay             integer
            bond_downdelay           integer
         LACP Configuration:
            lacp                     optional string, one of active, off, or passive
            other_config : lacp-system-id
                                     optional string
            other_config : lacp-system-priority
                                     optional string, containing an integer, in range 1 to 65,535
            other_config : lacp-time optional string, either fast or slow
            other_config : lacp-fallback-ab
                                     optional string, either true or false
         Rebalancing Configuration:
            other_config : bond-rebalance-interval
                                     optional  string,  containing  an  integer,  in  range  0 to
                                     2,147,483,647
         bond_fake_iface             boolean
       Spanning Tree Protocol:
         STP Configuration:
            other_config : stp-enable
                                     optional string, either true or false
            other_config : stp-port-num
                                     optional string, containing an integer, in range 1 to 255
            other_config : stp-port-priority
                                     optional string, containing an integer, in range 0 to 255
            other_config : stp-path-cost
                                     optional string, containing an integer, in range 0 to 65,535
         STP Status:
            status : stp_port_id     optional string
            status : stp_state       optional string,  one  of  blocking,  disabled,  forwarding,
                                     learning, or listening
            status : stp_sec_in_state
                                     optional string, containing an integer, at least 0
            status : stp_role        optional string, one of alternate, designated, or root
       Rapid Spanning Tree Protocol:
         RSTP Configuration:
            other_config : rstp-enable
                                     optional string, either true or false
            other_config : rstp-port-priority
                                     optional string, containing an integer, in range 0 to 240
            other_config : rstp-port-num
                                     optional string, containing an integer, in range 1 to 4,095
            other_config : rstp-path-cost
                                     optional string, containing an integer
            other_config : rstp-port-admin-edge
                                     optional string, either true or false
            other_config : rstp-port-auto-edge
                                     optional string, either true or false
            other_config : rstp-port-mcheck
                                     optional string, either true or false
         RSTP Status:
            rstp_status : rstp_port_id
                                     optional string
            rstp_status : rstp_port_role
                                     optional  string,  one  of  Alternate,  Backup,  Designated,
                                     Disabled, or Root
            rstp_status : rstp_port_state
                                     optional string, one of Disabled, Discarding, Forwarding, or
                                     Learning
            rstp_status : rstp_designated_bridge_id
                                     optional string
            rstp_status : rstp_designated_port_id
                                     optional string
            rstp_status : rstp_designated_path_cost
                                     optional string, containing an integer
         RSTP Statistics:
            rstp_statistics : rstp_tx_count
                                     optional integer
            rstp_statistics : rstp_rx_count
                                     optional integer
            rstp_statistics : rstp_error_count
                                     optional integer
            rstp_statistics : rstp_uptime
                                     optional integer
       Multicast Snooping:
         other_config : mcast-snooping-flood
                                     optional string, either true or false
         other_config : mcast-snooping-flood-reports
                                     optional string, either true or false
       Other Features:
         qos                         optional QoS
         mac                         optional string
         fake_bridge                 boolean
         protected                   boolean
         external_ids : fake-bridge-*
                                     optional string
         other_config : transient    optional string, either true or false
       bond_active_slave             optional string
       Port Statistics:
         Statistics: STP transmit and receive counters:
            statistics : stp_tx_count
                                     optional integer
            statistics : stp_rx_count
                                     optional integer
            statistics : stp_error_count
                                     optional integer
       Common Columns:
         other_config                map of string-string pairs
         external_ids                map of string-string pairs

   Details:
       name: immutable string (must be unique within table)
              Port  name. For a non-bonded port, this should be the same as its interface’s name.
              Port names must otherwise be unique among  the  names  of  ports,  interfaces,  and
              bridges  on  a  host.  Because  port and interfaces names are usually the same, the
              restrictions on the name column in the Interface  table,  particularly  on  length,
              also  apply  to  port  names.  Refer  to  the documentation for Interface names for
              details.

       interfaces: set of 1 or more Interfaces
              The port’s interfaces. If there is more than one, this is a bonded Port.

     VLAN Configuration:

       In short, a VLAN (short for ``virtual LAN’’) is a way to partition a  single  switch  into
       multiple  switches.  VLANs  can  be confusing, so for an introduction, please refer to the
       question ``What’s a VLAN?’’ in the Open vSwitch FAQ.

       A VLAN is sometimes encoded into a packet using a 802.1Q or 802.1ad VLAN header, but every
       packet  is  part  of  some VLAN whether or not it is encoded in the packet. (A packet that
       appears to have no VLAN is part of VLAN 0, by default.) As a result, it’s useful to  think
       of a VLAN as a metadata property of a packet, separate from how the VLAN is encoded. For a
       given port, this column determines how the encoding of a packet that ingresses or egresses
       the  port  maps  to  the  packet’s  VLAN.  When  a  packet  enters the switch, its VLAN is
       determined based on its setting in this column and its VLAN headers,  if  any,  and  then,
       conceptually,  the VLAN headers are then stripped off. Conversely, when a packet exits the
       switch, its VLAN and the settings in this column determine what VLAN headers, if any,  are
       pushed onto the packet before it egresses the port.

       The  VLAN configuration in this column affects Open vSwitch only when it is doing ``normal
       switching.’’ It does not affect flows set up by an OpenFlow  controller,  outside  of  the
       OpenFlow ``normal action.’’

       Bridge ports support the following types of VLAN configuration:

              trunk  A trunk port carries packets on one or more specified VLANs specified in the
                     trunks column (often, on every VLAN). A packet that  ingresses  on  a  trunk
                     port  is in the VLAN specified in its 802.1Q header, or VLAN 0 if the packet
                     has no 802.1Q header. A packet that egresses through a trunk port will  have
                     an 802.1Q header if it has a nonzero VLAN ID.

                     Any  packet  that ingresses on a trunk port tagged with a VLAN that the port
                     does not trunk is dropped.

              access An access port carries packets on exactly one  VLAN  specified  in  the  tag
                     column. Packets egressing on an access port have no 802.1Q header.

                     Any packet with an 802.1Q header with a nonzero VLAN ID that ingresses on an
                     access port is dropped, regardless of whether the VLAN ID in the  header  is
                     the access port’s VLAN ID.

              native-tagged
                     A  native-tagged  port  resembles  a  trunk  port, with the exception that a
                     packet without an 802.1Q header that ingresses on a native-tagged port is in
                     the ``native VLAN’’ (specified in the tag column).

              native-untagged
                     A  native-untagged  port  resembles a native-tagged port, with the exception
                     that a packet that egresses on a native-untagged port  in  the  native  VLAN
                     will not have an 802.1Q header.

              dot1q-tunnel
                     A dot1q-tunnel port is somewhat like an access port. Like an access port, it
                     carries packets on the single VLAN specified in  the  tag  column  and  this
                     VLAN,  called  the  service  VLAN,  does  not appear in an 802.1Q header for
                     packets that ingress or egress on the port. The main difference lies in  the
                     behavior  when  packets  that  include  a 802.1Q header ingress on the port.
                     Whereas an access port drops such packets, a dot1q-tunnel port treats  these
                     as double-tagged with the outer service VLAN tag and the inner customer VLAN
                     taken from the 802.1Q header. Correspondingly, to  egress  on  the  port,  a
                     packet  outer  VLAN  (or  only  VLAN)  must  be tag, which is removed before
                     egress, which exposes the inner (customer) VLAN if one is present.

                     If cvlans is set, only allows packets in the specified customer VLANs.

       A packet will only egress through bridge ports that carry  the  VLAN  of  the  packet,  as
       described by the rules above.

       vlan_mode:  optional  string, one of access, dot1q-tunnel, native-tagged, native-untagged,
       or trunk
              The VLAN mode of the port, as described above. When this column is empty, a default
              mode is selected as follows:

              •      If  tag  contains  a  value,  the  port is an access port. The trunks column
                     should be empty.

              •      Otherwise, the port is a trunk port. The trunks column value is  honored  if
                     it is present.

       tag: optional integer, in range 0 to 4,095
              For  an  access  port,  the  port’s  implicitly tagged VLAN. For a native-tagged or
              native-untagged port, the port’s native VLAN. Must be empty  if  this  is  a  trunk
              port.

       trunks: set of up to 4,096 integers, in range 0 to 4,095
              For  a trunk, native-tagged, or native-untagged port, the 802.1Q VLAN or VLANs that
              this port trunks; if it is empty, then the port trunks all VLANs. Must be empty  if
              this is an access port.

              A  native-tagged  or native-untagged port always trunks its native VLAN, regardless
              of whether trunks includes that VLAN.

       cvlans: set of up to 4,096 integers, in range 0 to 4,095
              For a dot1q-tunnel port, the customer VLANs that this port  includes.  If  this  is
              empty, the port includes all customer VLANs.

              For other kinds of ports, this setting is ignored.

       other_config : qinq-ethtype: optional string, either 802.1ad or 802.1q
              For  a  dot1q-tunnel  port,  this is the TPID for the service tag, that is, for the
              802.1Q header that contains the service VLAN  ID.  Because  packets  that  actually
              ingress  and  egress  a  dot1q-tunnel  port do not include an 802.1Q header for the
              service VLAN, this does not affect packets on the dot1q-tunnel port itself. Rather,
              it  determines  the service VLAN for a packet that ingresses on a dot1q-tunnel port
              and egresses on a trunk port.

              The value 802.1ad specifies TPID 0x88a8, which is also the default if  the  setting
              is omitted. The value 802.1q specifies TPID 0x8100.

              For other kinds of ports, this setting is ignored.

       other_config : priority-tags: optional string, one of always, if-nonzero, or never
              An  802.1Q  header  contains  two  important pieces of information: a VLAN ID and a
              priority. A frame with a zero VLAN  ID,  called  a  ``priority-tagged’’  frame,  is
              supposed  to  be  treated  the  same way as a frame without an 802.1Q header at all
              (except for the priority).

              However, some network elements ignore any frame that has 802.1Q header at all, even
              when  the  VLAN  ID  is  zero.  Therefore,  by default Open vSwitch does not output
              priority-tagged frames, instead omitting the 802.1Q header entirely if the VLAN  ID
              is zero. Set this key to if-nonzero to enable priority-tagged frames on a port.

              For  if-nonzero  Open vSwitch omits the 802.1Q header on output if both the VLAN ID
              and priority would be zero. Set to always to  retain  the  802.1Q  header  in  such
              frames as well.

              All frames output to native-tagged ports have a nonzero VLAN ID, so this setting is
              not meaningful on native-tagged ports.

     Bonding Configuration:

       A port that has more than one interface is a ``bonded  port.’’  Bonding  allows  for  load
       balancing and fail-over.

       The following types of bonding will work with any kind of upstream switch. On the upstream
       switch, do not configure the interfaces as a bond:

              balance-slb
                     Balances flows among members based on source MAC address  and  output  VLAN,
                     with periodic rebalancing as traffic patterns change.

              active-backup
                     Assigns  all  flows  to one member, failing over to a backup member when the
                     active member is disabled. This is the only bonding mode in which interfaces
                     may be plugged into different upstream switches.

       The  following  modes  require the upstream switch to support 802.3ad with successful LACP
       negotiation. If LACP negotiation fails and  other-config:lacp-fallback-ab  is  true,  then
       active-backup mode is used:

              balance-tcp
                     Balances flows among members based on L3 and L4 protocol information such as
                     IP addresses and TCP/UDP ports.

       These columns apply only to bonded ports. Their values are otherwise ignored.

       bond_mode: optional string, one of active-backup, balance-slb, or balance-tcp
              The type of bonding used for a bonded port. Defaults to active-backup if unset.

       other_config : bond-hash-basis: optional string, containing an integer
              An integer hashed along with flows when choosing output members  in  load  balanced
              bonds.  When  changed,  all  flows  will be assigned different hash values possibly
              causing member selection decisions to change. Does not affect bonding  modes  which
              do not employ load balancing such as active-backup.

       other_config : lb-output-action: optional string, either true or false
              Enable/disable usage of optimized lb_output action for balancing flows among output
              members in load balanced bonds in balance-tcp. When enabled, it uses optimized path
              for balance-tcp mode by using rss hash and avoids recirculation. This knob does not
              affect other balancing modes.

       other_config : bond-primary: optional string
              If a slave interface with this name exists in the bond and is up, it will  be  made
              active.   Relevant   only   when  other_config:bond_mode  is  active-backup  or  if
              balance-tcp  falls  back  to  active-backup  (e.g.,  LACP  negotiation  fails   and
              other_config:lacp-fallback-ab is true).

       other_config : all-members-active: optional string, either true or false
              Enable/Disable  delivery of broadcast/multicast packets on secondary interface of a
              balance-slb bond. Relevant only when lacp is off.

              This parameter is identical to all_slaves_active for Linux kernel  bonds.  Disabled
              by default as it is not a desirable configuration for most users.

     Link Failure Detection:

       An  important  part  of  link bonding is detecting that links are down so that they may be
       disabled. These settings determine how Open vSwitch detects link failure.

       other_config : bond-detect-mode: optional string, either carrier or miimon
              The means used to detect  link  failures.  Defaults  to  carrier  which  uses  each
              interface’s carrier to detect failures. When set to miimon, will check for failures
              by polling each interface’s MII.

       other_config : bond-miimon-interval: optional string, containing an integer
              The interval, in milliseconds, between successive attempts to poll each interface’s
              MII. Relevant only when other_config:bond-detect-mode is miimon.

       bond_updelay: integer
              The  number  of milliseconds for which the link must stay up on an interface before
              the  interface  is  considered  to  be  up.  Specify  0  to  enable  the  interface
              immediately.

              This setting is honored only when at least one bonded interface is already enabled.
              When no interfaces are enabled, then the first bond interface to come up is enabled
              immediately.

       bond_downdelay: integer
              The number of milliseconds for which the link must stay down on an interface before
              the interface is considered  to  be  down.  Specify  0  to  disable  the  interface
              immediately.

     LACP Configuration:

       LACP,  the  Link Aggregation Control Protocol, is an IEEE standard that allows switches to
       automatically detect that they are connected by multiple links and aggregate across  those
       links. These settings control LACP behavior.

       lacp: optional string, one of active, off, or passive
              Configures  LACP on this port. LACP allows directly connected switches to negotiate
              which links may be bonded. LACP may be enabled on non-bonded ports for the  benefit
              of any switches they may be connected to. active ports are allowed to initiate LACP
              negotiations. passive  ports  are  allowed  to  participate  in  LACP  negotiations
              initiated  by  a  remote  switch,  but  not  allowed  to initiate such negotiations
              themselves. If LACP is enabled on a port whose  partner  switch  does  not  support
              LACP,  the  bond  will  be disabled, unless other-config:lacp-fallback-ab is set to
              true. Defaults to off if unset.

       other_config : lacp-system-id: optional string
              The LACP system ID of this Port. The system ID of a LACP bond is used  to  identify
              itself  to  its  partners.  Must  be  a nonzero MAC address. Defaults to the bridge
              Ethernet address if unset.

       other_config : lacp-system-priority: optional string, containing an integer, in range 1 to
       65,535
              The  LACP system priority of this Port. In LACP negotiations, link status decisions
              are made by the system with the numerically lower priority.

       other_config : lacp-time: optional string, either fast or slow
              The LACP timing which should be used on this Port. By default slow  is  used.  When
              configured  to  be  fast LACP heartbeats are requested at a rate of once per second
              causing connectivity problems to be detected more quickly. In slow mode, heartbeats
              are requested at a rate of once every 30 seconds.

       other_config : lacp-fallback-ab: optional string, either true or false
              Determines  the  behavior  of  openvswitch bond in LACP mode. If the partner switch
              does not support LACP, setting this option to true allows openvswitch  to  fallback
              to active-backup. If the option is set to false, the bond will be disabled. In both
              the cases, once the partner switch is configured to LACP mode, the  bond  will  use
              LACP.

     Rebalancing Configuration:

       These settings control behavior when a bond is in balance-slb or balance-tcp mode.

       other_config : bond-rebalance-interval: optional string, containing an integer, in range 0
       to 2,147,483,647
              For a load balanced bonded port, the  number  of  milliseconds  between  successive
              attempts  to  rebalance  the bond, that is, to move flows from one interface on the
              bond to another in an attempt to keep usage of each  interface  roughly  equal.  If
              zero,  load  balancing  is  disabled on the bond (link failure still cause flows to
              move). If less than 1000ms, the rebalance interval will be 1000ms.

       bond_fake_iface: boolean
              For a bonded port, whether to create a fake internal interface with the name of the
              port. Use only for compatibility with legacy software that requires this.

     Spanning Tree Protocol:

       The  configuration  here  is  only  meaningful,  and  the  status  is only populated, when
       802.1D-1998 Spanning Tree Protocol is enabled on the port’s  Bridge  with  its  stp_enable
       column.

     STP Configuration:

       other_config : stp-enable: optional string, either true or false
              When  STP  is  enabled on a bridge, it is enabled by default on all of the bridge’s
              ports except bond, internal, and mirror ports (which do not work with STP). If this
              column’s value is false, STP is disabled on the port.

       other_config : stp-port-num: optional string, containing an integer, in range 1 to 255
              The  port  number used for the lower 8 bits of the port-id. By default, the numbers
              will be assigned automatically. If any port’s number is manually  configured  on  a
              bridge, then they must all be.

       other_config  :  stp-port-priority:  optional string, containing an integer, in range 0 to
       255
              The port’s relative priority value for determining the root port (the upper 8  bits
              of  the  port-id).  A port with a lower port-id will be chosen as the root port. By
              default, the priority is 0x80.

       other_config : stp-path-cost: optional string, containing an integer, in range 0 to 65,535
              Spanning tree path cost for the port. A lower number indicates a  faster  link.  By
              default, the cost is based on the maximum speed of the link.

     STP Status:

       status : stp_port_id: optional string
              The  port  ID  used in spanning tree advertisements for this port, as 4 hex digits.
              Configuring the port ID is described in the stp-port-num and stp-port-priority keys
              of the other_config section earlier.

       status  :  stp_state: optional string, one of blocking, disabled, forwarding, learning, or
       listening
              STP state of the port.

       status : stp_sec_in_state: optional string, containing an integer, at least 0
              The amount of time this port has been in the current STP state, in seconds.

       status : stp_role: optional string, one of alternate, designated, or root
              STP role of the port.

     Rapid Spanning Tree Protocol:

       The configuration here is  only  meaningful,  and  the  status  and  statistics  are  only
       populated,  when  802.1D-1998  Spanning Tree Protocol is enabled on the port’s Bridge with
       its stp_enable column.

     RSTP Configuration:

       other_config : rstp-enable: optional string, either true or false
              When RSTP is enabled on a bridge, it is enabled by default on all of  the  bridge’s
              ports  except  bond,  internal,  and mirror ports (which do not work with RSTP). If
              this column’s value is false, RSTP is disabled on the port.

       other_config : rstp-port-priority: optional string, containing an integer, in range  0  to
       240
              The  port’s  relative priority value for determining the root port, in multiples of
              16. By default, the port priority is 0x80 (128). Any value in the lower 4  bits  is
              rounded off. The significant upper 4 bits become the upper 4 bits of the port-id. A
              port with the lowest port-id is elected as the root.

       other_config : rstp-port-num: optional string, containing an integer, in range 1 to 4,095
              The local RSTP port number, used as the lower 12 bits of the  port-id.  By  default
              the  port  numbers  are assigned automatically, and typically may not correspond to
              the OpenFlow port numbers. A port with the lowest port-id is elected as the root.

       other_config : rstp-path-cost: optional string, containing an integer
              The port path cost. The Port’s contribution, when it is the Root Port, to the  Root
              Path  Cost for the Bridge. By default the cost is automatically calculated from the
              port’s speed.

       other_config : rstp-port-admin-edge: optional string, either true or false
              The admin edge port parameter for the Port. Default is false.

       other_config : rstp-port-auto-edge: optional string, either true or false
              The auto edge port parameter for the Port. Default is true.

       other_config : rstp-port-mcheck: optional string, either true or false
              The mcheck port parameter for the Port. Default is false. May be set to  force  the
              Port  Protocol  Migration  state  machine  to  transmit RST BPDUs for a MigrateTime
              period, to test whether all STP Bridges on the attached LAN have been  removed  and
              the  Port  can continue to transmit RSTP BPDUs. Setting mcheck has no effect if the
              Bridge is operating in STP Compatibility mode.

              Changing the value from true to false has no effect, but needs to be done  if  this
              behavior  is to be triggered again by subsequently changing the value from false to
              true.

     RSTP Status:

       rstp_status : rstp_port_id: optional string
              The port ID used in spanning tree advertisements for this port, as  4  hex  digits.
              Configuring  the  port  ID is described in the rstp-port-num and rstp-port-priority
              keys of the other_config section earlier.

       rstp_status : rstp_port_role: optional  string,  one  of  Alternate,  Backup,  Designated,
       Disabled, or Root
              RSTP role of the port.

       rstp_status  :  rstp_port_state: optional string, one of Disabled, Discarding, Forwarding,
       or Learning
              RSTP state of the port.

       rstp_status : rstp_designated_bridge_id: optional string
              The   port’s   RSTP   designated   bridge    ID,    in    the    same    form    as
              rstp_status:rstp_bridge_id in the Bridge table.

       rstp_status : rstp_designated_port_id: optional string
              The port’s RSTP designated port ID, as 4 hex digits.

       rstp_status : rstp_designated_path_cost: optional string, containing an integer
              The port’s RSTP designated path cost. Lower is better.

     RSTP Statistics:

       rstp_statistics : rstp_tx_count: optional integer
              Number of RSTP BPDUs transmitted through this port.

       rstp_statistics : rstp_rx_count: optional integer
              Number of valid RSTP BPDUs received by this port.

       rstp_statistics : rstp_error_count: optional integer
              Number of invalid RSTP BPDUs received by this port.

       rstp_statistics : rstp_uptime: optional integer
              The duration covered by the other RSTP statistics, in seconds.

     Multicast Snooping:

       other_config : mcast-snooping-flood: optional string, either true or false
              If set to true, multicast packets (except Reports) are unconditionally forwarded to
              the specific port.

       other_config : mcast-snooping-flood-reports: optional string, either true or false
              If set to true, multicast Reports are unconditionally  forwarded  to  the  specific
              port.

     Other Features:

       qos: optional QoS
              Quality of Service configuration for this port.

       mac: optional string
              The  MAC  address to use for this port for the purpose of choosing the bridge’s MAC
              address. This column does not necessarily reflect the port’s  actual  MAC  address,
              nor will setting it change the port’s actual MAC address.

       fake_bridge: boolean
              Does  this  port  represent a sub-bridge for its tagged VLAN within the Bridge? See
              ovs-vsctl(8) for more information.

       protected: boolean
              The protected ports feature allows certain ports to  be  designated  as  protected.
              Traffic  between  protected  ports  is blocked. Protected ports can send traffic to
              unprotected ports. Unprotected ports can send  traffic  to  any  port.  Default  is
              false.

       external_ids : fake-bridge-*: optional string
              External  IDs  for  a  fake  bridge  (see  the  fake_bridge  column) are defined by
              prefixing a Bridge external_ids key with fake-bridge-, e.g. fake-bridge-bridge-id.

       other_config : transient: optional string, either true or false
              If   set   to   true,   the   port   will   be   removed   when    ovs-ctl    start
              --delete-transient-ports is used.

       bond_active_slave: optional string
              For a bonded port, record the MAC address of the current active member.

     Port Statistics:

       Key-value  pairs  that  report  port  statistics.  The  update  period  is  controlled  by
       other_config:stats-update-interval in the Open_vSwitch table.

     Statistics: STP transmit and receive counters:

       statistics : stp_tx_count: optional integer
              Number of STP BPDUs sent on this port by the spanning tree library.

       statistics : stp_rx_count: optional integer
              Number of STP BPDUs received on  this  port  and  accepted  by  the  spanning  tree
              library.

       statistics : stp_error_count: optional integer
              Number  of  bad STP BPDUs received on this port. Bad BPDUs include runt packets and
              those with an unexpected protocol ID.

     Common Columns:

       The overall purpose of these columns is described under Common Columns at the beginning of
       this document.

       other_config: map of string-string pairs

       external_ids: map of string-string pairs

Interface TABLE

       An interface within a Port.

   Summary:
       Core Features:
         name                        immutable string (must be unique within table)
         ifindex                     optional integer, in range 0 to 4,294,967,295
         mac_in_use                  optional string
         mac                         optional string
         error                       optional string
         OpenFlow Port Number:
            ofport                   optional integer
            ofport_request           optional integer, in range 1 to 65,279
       System-Specific Details:
         type                        string
       Tunnel Options:
         options : remote_ip         optional string
         options : local_ip          optional string
         options : in_key            optional string
         options : out_key           optional string
         options : dst_port          optional string
         options : key               optional string
         options : tos               optional string
         options : ttl               optional string
         options : df_default        optional string, either true or false
         options : egress_pkt_mark   optional string
         Tunnel Options: lisp only:
            options : packet_type    optional string, either legacy_l3 or ptap
         Tunnel Options: vxlan only:
            options : exts           optional string
            options : packet_type    optional string, one of legacy_l2, legacy_l3, or ptap
         Tunnel Options: gre only:
            options : packet_type    optional string, one of legacy_l2, legacy_l3, or ptap
            options : seq            optional string, either true or false
         Tunnel Options: gre, ip6gre, geneve, bareudp and vxlan:
            options : csum           optional string, either true or false
         Tunnel Options: IPsec:
            options : psk            optional string
            options : remote_cert    optional string
            options : remote_name    optional string
       Tunnel Options: erspan only:
         options : erspan_idx        optional string
         options : erspan_ver        optional string
         options : erspan_dir        optional string
         options : erspan_hwid       optional string
       Tunnel Options: Bareudp only:
         options : payload_type      optional string
       Tunnel Options: srv6 only:
         options : srv6_segs         optional string
         options : srv6_flowlabel    optional string, one of compute, copy, or zero
       Patch Options:
         options : peer              optional string
       PMD (Poll Mode Driver) Options:
         options : n_rxq             optional string, containing an integer, at least 1
         options : dpdk-devargs      optional string
         other_config : pmd-rxq-affinity
                                     optional string
         options : xdp-mode          optional    string,    one    of    best-effort,    generic,
                                     native-with-zerocopy, or native
         options : use-need-wakeup   optional string, either true or false
         options : vhost-server-path
                                     optional string
         options : tx-retries-max    optional string, containing an integer, in range 0 to 32
         options : n_rxq_desc        optional string, containing an integer, in range 1 to 4,096
         options : n_txq_desc        optional string, containing an integer, in range 1 to 4,096
         options : dpdk-vf-mac       optional string
         options : rx-steering       optional string, either rss+lacp or rss
         other_config : tx-steering  optional string, either hash or thread
       EMC (Exact Match Cache) Configuration:
         other_config : emc-enable   optional string, either true or false
       MTU:
         mtu                         optional integer
         mtu_request                 optional integer, at least 1
       Interface Status:
         admin_state                 optional string, either down or up
         link_state                  optional string, either down or up
         link_resets                 optional integer
         link_speed                  optional integer
         duplex                      optional string, either full or half
         lacp_current                optional boolean
         status                      map of string-string pairs
         status : driver_name        optional string
         status : driver_version     optional string
         status : firmware_version   optional string
         status : source_ip          optional string
         status : tunnel_egress_iface
                                     optional string
         status : tunnel_egress_iface_carrier
                                     optional string, either down or up
         dpdk:
            status : port_no         optional string
            status : numa_id         optional string
            status : min_rx_bufsize  optional string
            status : max_rx_pktlen   optional string
            status : max_rx_queues   optional string
            status : max_tx_queues   optional string
            status : max_mac_addrs   optional string
            status : max_hash_mac_addrs
                                     optional string
            status : max_vfs         optional string
            status : max_vmdq_pools  optional string
            status : if_type         optional string
            status : if_descr        optional string
            status : bus_info        optional string
            status : dpdk-vf-mac     optional string
            status : rx_steering     optional string
            status : rx_steering_queue
                                     optional string
            status : rss_queues      optional string
         dpdkvhostuser:
            status : mode            optional string
            status : features        optional string
            status : num_of_vrings   optional string
            status : numa            optional string
            status : socket          optional string
            status : status          optional string
            status : vring_n_size    optional string
            status : userspace-tso   optional string
       Statistics:
         Statistics: Successful transmit and receive counters:
            statistics : rx_packets  optional integer
            statistics : rx_bytes    optional integer
            statistics : tx_packets  optional integer
            statistics : tx_bytes    optional integer
         Statistics: Receive errors:
            statistics : rx_dropped  optional integer
            statistics : rx_frame_err
                                     optional integer
            statistics : rx_over_err optional integer
            statistics : rx_crc_err  optional integer
            statistics : rx_errors   optional integer
         Statistics: Transmit errors:
            statistics : tx_dropped  optional integer
            statistics : collisions  optional integer
            statistics : tx_errors   optional integer
       Ingress Policing:
         ingress_policing_rate       integer, at least 0
         ingress_policing_kpkts_rate
                                     integer, at least 0
         ingress_policing_burst      integer, at least 0
         ingress_policing_kpkts_burst
                                     integer, at least 0
       Bidirectional Forwarding Detection (BFD):
         BFD Configuration:
            bfd : enable             optional string, either true or false
            bfd : min_rx             optional string, containing an integer, at least 1
            bfd : min_tx             optional string, containing an integer, at least 1
            bfd : decay_min_rx       optional string, containing an integer
            bfd : forwarding_if_rx   optional string, either true or false
            bfd : cpath_down         optional string, either true or false
            bfd : check_tnl_key      optional string, either true or false
            bfd : bfd_local_src_mac  optional string
            bfd : bfd_local_dst_mac  optional string
            bfd : bfd_remote_dst_mac optional string
            bfd : bfd_src_ip         optional string
            bfd : bfd_dst_ip         optional string
            bfd : oam                optional string
            bfd : mult               optional string, containing an integer, in range 1 to 255
         BFD Status:
            bfd_status : state       optional string, one of admin_down, down, init, or up
            bfd_status : forwarding  optional string, either true or false
            bfd_status : diagnostic  optional string
            bfd_status : remote_state
                                     optional string, one of admin_down, down, init, or up
            bfd_status : remote_diagnostic
                                     optional string
            bfd_status : flap_count  optional string, containing an integer, at least 0
       Connectivity Fault Management:
         cfm_mpid                    optional integer
         cfm_flap_count              optional integer
         cfm_fault                   optional boolean
         cfm_fault_status : recv     none
         cfm_fault_status : rdi      none
         cfm_fault_status : maid     none
         cfm_fault_status : loopback
                                     none
         cfm_fault_status : overflow
                                     none
         cfm_fault_status : override
                                     none
         cfm_fault_status : interval
                                     none
         cfm_remote_opstate          optional string, either down or up
         cfm_health                  optional integer, in range 0 to 100
         cfm_remote_mpids            set of integers
         other_config : cfm_interval
                                     optional string, containing an integer
         other_config : cfm_extended
                                     optional string, either true or false
         other_config : cfm_demand   optional string, either true or false
         other_config : cfm_opstate  optional string, either down or up
         other_config : cfm_ccm_vlan
                                     optional string, containing an integer, in range 1 to 4,095
         other_config : cfm_ccm_pcp  optional string, containing an integer, in range 1 to 7
       Bonding Configuration:
         other_config : lacp-port-id
                                     optional string, containing an integer, in range 1 to 65,535
         other_config : lacp-port-priority
                                     optional string, containing an integer, in range 1 to 65,535
         other_config : lacp-aggregation-key
                                     optional string, containing an integer, in range 1 to 65,535
       Virtual Machine Identifiers:
         external_ids : attached-mac
                                     optional string
         external_ids : iface-id     optional string
         external_ids : iface-status
                                     optional string, either active or inactive
         external_ids : vm-id        optional string
       Auto Attach Configuration:
         lldp : enable               optional string, either true or false
       Flow control Configuration:
         options : rx-flow-ctrl      optional string, either true or false
         options : tx-flow-ctrl      optional string, either true or false
         options : flow-ctrl-autoneg
                                     optional string, either true or false
       Link State Change detection mode:
         options : dpdk-lsc-interrupt
                                     optional string, either true or false
       Common Columns:
         other_config                map of string-string pairs
         external_ids                map of string-string pairs

   Details:
     Core Features:

       name: immutable string (must be unique within table)
              Interface name. Should be alphanumeric. For non-bonded port,  this  should  be  the
              same  as  the  port  name.  It  must  otherwise be unique among the names of ports,
              interfaces, and bridges on a host.

              The maximum length of an interface name depends on the underlying datapath:

              •      The names of interfaces  implemented  as  Linux  and  BSD  network  devices,
                     including  interfaces  with type internal, tap, or system plus the different
                     types of tunnel ports, are limited to 15 bytes. Windows limits  these  names
                     to 255 bytes.

              •      The  names  of  patch  ports  are  not  used  in the underlying datapath, so
                     operating system restrictions do not apply. Thus, they  may  have  arbitrary
                     length.

              Regardless of other restrictions, OpenFlow only supports 15-byte names, which means
              that ovs-ofctl and OpenFlow controllers will show names truncated to 15 bytes.

       ifindex: optional integer, in range 0 to 4,294,967,295
              A positive interface index as defined for SNMP MIB-II in RFCs 1213 and 2863, if the
              interface has one, otherwise 0. The ifindex is useful for seamless integration with
              protocols such as SNMP and sFlow.

       mac_in_use: optional string
              The MAC address in use by this interface.

       mac: optional string
              Ethernet address to set for this interface. If unset then the default  MAC  address
              is used:

              •      For  the  local  interface,  the  default is the lowest-numbered MAC address
                     among the other bridge ports, either the  value  of  the  mac  in  its  Port
                     record,  if  set, or its actual MAC (for bonded ports, the MAC of its member
                     whose name is first in alphabetical order). Internal ports and bridge  ports
                     that  are  used  as  port  mirroring destinations (see the Mirror table) are
                     ignored.

              •      For other internal interfaces, the default MAC is randomly generated.

              •      External interfaces typically have  a  MAC  address  associated  with  their
                     hardware.

              Some  interfaces may not have a software-controllable MAC address. This option only
              affects internal ports. For other type  ports,  you  can  change  the  MAC  address
              outside Open vSwitch, using ip command.

       error: optional string
              If the configuration of the port failed, as indicated by -1 in ofport, Open vSwitch
              sets this column to an error description in human readable  form.  Otherwise,  Open
              vSwitch clears this column.

     OpenFlow Port Number:

       When  a  client adds a new interface, Open vSwitch chooses an OpenFlow port number for the
       new port. If the client that adds the port fills  in  ofport_request,  then  Open  vSwitch
       tries  to  use  its value as the OpenFlow port number. Otherwise, or if the requested port
       number is already in use or cannot be used for another reason, Open vSwitch  automatically
       assigns  a  free port number. Regardless of how the port number was obtained, Open vSwitch
       then reports in ofport the port number actually assigned.

       Open vSwitch limits the port numbers that it automatically assigns to the range 1  through
       32,767, inclusive. Controllers therefore have free use of ports 32,768 and up.

       ofport: optional integer
              OpenFlow  port number for this interface. Open vSwitch sets this column’s value, so
              other clients should treat it as read-only.

              The OpenFlow ``local’’ port (OFPP_LOCAL) is 65,534. The other  valid  port  numbers
              are  in  the  range  1 to 65,279, inclusive. Value -1 indicates an error adding the
              interface.

       ofport_request: optional integer, in range 1 to 65,279
              Requested OpenFlow port number for this interface.

              A client should ideally set this column’s value in the  same  database  transaction
              that it uses to create the interface. Open vSwitch version 2.1 and later will honor
              a later request for  a  specific  port  number,  althuogh  it  might  confuse  some
              controllers: OpenFlow does not have a way to announce a port number change, so Open
              vSwitch represents it over OpenFlow as a port deletion followed  immediately  by  a
              port addition.

              If  ofport_request  is  set  or changed to some other port’s automatically assigned
              port number, Open vSwitch chooses a new port number for the latter port.

     System-Specific Details:

       type: string
              The interface type. The types supported by a particular instance  of  Open  vSwitch
              are listed in the iface_types column in the Open_vSwitch table. The following types
              are defined:

              system An ordinary network device, e.g. eth0 on Linux.  Sometimes  referred  to  as
                     ``external  interfaces’’  since  they  are  generally  connected to hardware
                     external to that on which the Open vSwitch is running. The empty string is a
                     synonym for system.

              internal
                     A  simulated  network  device  that  sends and receives traffic. An internal
                     interface whose name is the same as its bridge’s name is called the  ``local
                     interface.’’  It  does  not make sense to bond an internal interface, so the
                     terms ``port’’ and ``interface’’ are often  used  imprecisely  for  internal
                     interfaces.

              tap    A TUN/TAP device managed by Open vSwitch.

                     Open  vSwitch  checks the interface state before send packets to the device.
                     When it is down, the packets are dropped and  the  tx_dropped  statistic  is
                     updated  accordingly.  Older  versions  of  Open  vSwitch  did not check the
                     interface  state  and  then  the  tx_packets  was  incremented  along   with
                     tx_dropped.

              geneve An  Ethernet over Geneve (http://tools.ietf.org/html/draft-ietf-nvo3-geneve)
                     IPv4/IPv6 tunnel. A description of how to match and set Geneve  options  can
                     be found in the ovs-ofctl manual page.

              gre    Generic  Routing  Encapsulation  (GRE)  over  IPv4  tunnel,  configurable to
                     encapsulate layer 2 or layer 3 traffic.

              ip6gre Generic Routing Encapsulation (GRE) over IPv6 tunnel,  encapsulate  layer  2
                     traffic.

              vxlan  An Ethernet tunnel over the UDP-based VXLAN protocol described in RFC 7348.

                     Open  vSwitch  uses IANA-assigned UDP destination port 4789. The source port
                     used for VXLAN traffic varies on a per-flow basis and is  in  the  ephemeral
                     port range.

              lisp   A  layer  3  tunnel  over  the experimental, UDP-based Locator/ID Separation
                     Protocol (RFC 6830).

                     Only IPv4 and IPv6 packets are supported by the protocol, and they are  sent
                     and  received  without  an  Ethernet  header.  Traffic to/from LISP ports is
                     expected to be configured explicitly, and the  ports  are  not  intended  to
                     participate  in  learning based switching. As such, they are always excluded
                     from packet flooding.

              stt    The Stateless TCP Tunnel (STT) is particularly useful when tunnel  endpoints
                     are  in  end-systems,  as  it  utilizes the capabilities of standard network
                     interface cards to improve  performance.  STT  utilizes  a  TCP-like  header
                     inside  the  IP  header.  It  is stateless, i.e., there is no TCP connection
                     state of any kind associated with the tunnel. The TCP-like header is used to
                     leverage  the  capabilities  of existing network interface cards, but should
                     not be  interpreted  as  implying  any  sort  of  connection  state  between
                     endpoints.  Since  the  STT  protocol does not engage in the usual TCP 3-way
                     handshake, so it will have difficulty  traversing  stateful  firewalls.  The
                     protocol  is  documented  at https://tools.ietf.org/html/draft-davie-stt All
                     traffic uses a default destination port of 7471.

              patch  A pair of virtual devices that act as a patch cable.

              gtpu   GPRS  Tunneling  Protocol  (GTP)  is  a  group  of  IP-based  communications
                     protocols used to carry general packet radio service (GPRS) within GSM, UMTS
                     and LTE networks. GTP-U is used for carrying user data within the GPRS  core
                     network  and between the radio access network and the core network. The user
                     data transported can be packets in any of IPv4, IPv6, or PPP formats.

                     The protocol is documented at http://www.3gpp.org/DynaReport/29281.htm

                     Open vSwitch uses UDP destination port 2152. The source port  used  for  GTP
                     traffic varies on a per-flow basis and is in the ephemeral port range.

              Bareudp
                     The   Bareudp  tunnel  provides  a  generic  L3  encapsulation  support  for
                     tunnelling different L3 protocols like MPLS,  IP,  NSH  etc.  inside  a  UDP
                     tunnel.

              srv6   Segment Routing IPv6 (SRv6) tunnel encapsulates L3 traffic as "IPv6 in IPv6"
                     or "IPv4 in IPv6" with Segment Routing Header (SRH) defined in RFC 8754. The
                     segment list in SRH can be set using a SRv6 specific option.

     Tunnel Options:

       These  options apply to interfaces with type of geneve, bareudp, gre, ip6gre, vxlan, lisp,
       stt and srv6.

       Each tunnel must be uniquely identified by the  combination  of  type,  options:remote_ip,
       options:local_ip,  and  options:in_key.  If two ports are defined that are the same except
       one has an optional identifier and the other does not, the more specific  one  is  matched
       first.  options:in_key is considered more specific than options:local_ip if a port defines
       one and another port defines the other. options:in_key is not applicable for  bareudp  and
       srv6 tunnels. Hence it is not considered while identifying bareudp or srv6 tunnels.

       options : remote_ip: optional string
              Required. The remote tunnel endpoint, one of:

              •      An  IPv4  or IPv6 address (not a DNS name), e.g. 192.168.0.123. Only unicast
                     endpoints are supported.

              •      The word flow. The tunnel accepts packets from any remote  tunnel  endpoint.
                     To  process  only  packets  from a specific remote tunnel endpoint, the flow
                     entries may match on the tun_src or tun_ipv6_srcfield. When sending  packets
                     to a remote_ip=flow tunnel, the flow actions must explicitly set the tun_dst
                     or tun_ipv6_dst field to  the  IP  address  of  the  desired  remote  tunnel
                     endpoint, e.g. with a set_field action.

              The  remote  tunnel  endpoint for any packet received from a tunnel is available in
              the tun_src field for matching in the flow table.

       options : local_ip: optional string
              Optional. The tunnel destination IP that received packets must match. Default is to
              match all addresses. If specified, may be one of:

              •      An IPv4/IPv6 address (not a DNS name), e.g. 192.168.12.3.

              •      The  word  flow.  The  tunnel  accepts  packets  sent to any of the local IP
                     addresses of the system running OVS. To  process  only  packets  sent  to  a
                     specific  IP  address,  the  flow  entries  may  match  on  the  tun_dst  or
                     tun_ipv6_dst field. When sending packets to a local_ip=flow tunnel, the flow
                     actions  may explicitly set the tun_src or tun_ipv6_src field to the desired
                     IP address, e.g.  with  a  set_field  action.  However,  while  routing  the
                     tunneled  packet  out,  the  local system may override the specified address
                     with the local IP address configured for the outgoing system interface.

                     This  option  is  valid  only  for  tunnels   also   configured   with   the
                     remote_ip=flow option.

              The  tunnel  destination  IP  address  for  any  packet  received  from a tunnel is
              available in the tun_dst or tun_ipv6_dst field for matching in the flow table.

       options : in_key: optional string
              Optional, not applicable for bareudp and srv6. The key that received  packets  must
              contain, one of:

              •      0.  The  tunnel  receives  packets  with  no key or with a key of 0. This is
                     equivalent to specifying no options:in_key at all.

              •      A positive 24-bit (for Geneve, VXLAN, and LISP), 32-bit (for GRE) or  64-bit
                     (for STT) number. The tunnel receives only packets with the specified key.

              •      The  word  flow.  The  tunnel  accepts packets with any key. The key will be
                     placed in the tun_id field for matching in the flow table. The ovs-fields(7)
                     manual  page  contains  additional  information  about  matching  fields  in
                     OpenFlow flows.

       options : out_key: optional string
              Optional, not applicable for bareudp and srv6.  The  key  to  be  set  on  outgoing
              packets, one of:

              •      0.  Packets  sent through the tunnel will have no key. This is equivalent to
                     specifying no options:out_key at all.

              •      A positive 24-bit (for Geneve, VXLAN and LISP), 32-bit (for GRE)  or  64-bit
                     (for  STT)  number.  Packets sent through the tunnel will have the specified
                     key.

              •      The word flow. Packets sent through the tunnel will have the key  set  using
                     the set_tunnel Nicira OpenFlow vendor extension (0 is used in the absence of
                     an action). The ovs-fields(7) manual page  contains  additional  information
                     about the Nicira OpenFlow vendor extensions.

       options : dst_port: optional string
              Optional. The tunnel transport layer destination port, for UDP and TCP based tunnel
              protocols (Geneve, VXLAN, LISP, and STT).

       options : key: optional string
              Optional. Shorthand to set in_key and out_key at the same time.

       options : tos: optional string
              Optional. The value of the ToS bits to be set on the encapsulating packet.  ToS  is
              interpreted  as  DSCP  and ECN bits, ECN part must be zero. It may also be the word
              inherit, in which case the ToS will be copied from the inner packet if it  is  IPv4
              or  IPv6  (otherwise it will be 0). The ECN fields are always inherited. Default is
              0.

       options : ttl: optional string
              Optional. The TTL to be set on the encapsulating packet. It may also  be  the  word
              inherit,  in  which case the TTL will be copied from the inner packet if it is IPv4
              or IPv6 (otherwise it will be the system default, typically  64).  Default  is  the
              system default TTL.

       options : df_default: optional string, either true or false
              Optional. If enabled, the Don’t Fragment bit will be set on tunnel outer headers to
              allow path MTU discovery. Default is enabled; set to false to disable.

       options : egress_pkt_mark: optional string
              Optional. The pkt_mark to be set on the  encapsulating  packet.  This  option  sets
              packet  mark  for  the  tunnel  endpoint  for  all  tunnel packets including tunnel
              monitoring.

     Tunnel Options: lisp only:

       options : packet_type: optional string, either legacy_l3 or ptap
              A LISP tunnel sends and receives only IPv4 and IPv6 packets. This  option  controls
              what how the tunnel represents the packets that it sends and receives:

              •      By default, or if this option is legacy_l3, the tunnel represents packets as
                     Ethernet frames for compatibility  with  legacy  OpenFlow  controllers  that
                     expect this behavior.

              •      If  this option is ptap, the tunnel represents packets using the packet_type
                     mechanism introduced in OpenFlow 1.5.

     Tunnel Options: vxlan only:

       options : exts: optional string
              Optional. Comma  separated  list  of  optional  VXLAN  extensions  to  enable.  The
              following extensions are supported:

              •      gbp:  VXLAN-GBP  allows  to  transport  the group policy context of a packet
                     across the VXLAN tunnel to other  network  peers.  See  the  description  of
                     tun_gbp_id  and  tun_gbp_flags  in ovs-fields(7) for additional information.
                     (https://tools.ietf.org/html/draft-smith-vxlan-group-policy)

              •      gpe: Support for Generic Protocol  Encapsulation  in  accordance  with  IETF
                     draft  https://tools.ietf.org/html/draft-ietf-nvo3-vxlan-gpe.  Without  this
                     option, a VXLAN packet always encapsulates  an  Ethernet  frame.  With  this
                     option,  an  VXLAN  packet  may also encapsulate an IPv4, IPv6, NSH, or MPLS
                     packet.

       options : packet_type: optional string, one of legacy_l2, legacy_l3, or ptap
              This option controls what types of packets the tunnel sends and receives and how it
              represents them:

              •      By  default,  or  if this option is legacy_l2, the tunnel sends and receives
                     only Ethernet frames.

              •      If this option is legacy_l3, the tunnel sends and receives only non-Ethernet
                     (L3)  packet,  but  the  packets  are  represented  as  Ethernet  frames for
                     compatibility with legacy OpenFlow controllers that  expect  this  behavior.
                     This requires enabling gpe in options:exts.

              •      If  this option is ptap, Open vSwitch represents packets in the tunnel using
                     the  packet_type  mechanism  introduced  in  OpenFlow  1.5.  This  mechanism
                     supports any kind of packet, but actually sending and receiving non-Ethernet
                     packets requires additionally enabling gpe in options:exts.

     Tunnel Options: gre only:

       gre interfaces support these options.

       options : packet_type: optional string, one of legacy_l2, legacy_l3, or ptap
              This option controls what types of packets the tunnel sends and receives and how it
              represents them:

              •      By  default,  or  if this option is legacy_l2, the tunnel sends and receives
                     only Ethernet frames.

              •      If this option is legacy_l3, the tunnel sends and receives only non-Ethernet
                     (L3)  packet,  but  the  packets  are  represented  as  Ethernet  frames for
                     compatibility with legacy OpenFlow controllers that expect this behavior.

              •      The legacy_l3 option is only available via the user space datapath. The  OVS
                     kernel  datapath  does not support devices of type ARPHRD_IPGRE which is the
                     requirement for legacy_l3 type packets.

              •      If this option is ptap, the tunnel sends and receives any  kind  of  packet.
                     Open  vSwitch  represents  packets  in  the  tunnel  using  the  packet_type
                     mechanism introduced in OpenFlow 1.5.

       options : seq: optional string, either true or false
              Optional. A 4-byte sequence number field for GRE tunnel only. Default is  disabled,
              set  to  true  to  enable.  Sequence  number is incremented by one on each outgoing
              packet.

     Tunnel Options: gre, ip6gre, geneve, bareudp and vxlan:

       gre, ip6gre, geneve, bareudp and vxlan interfaces support these options.

       options : csum: optional string, either true or false
              Optional. Compute encapsulation header (either GRE or UDP)  checksums  on  outgoing
              packets.  Default is disabled, set to true to enable. Checksums present on incoming
              packets will be validated regardless of this setting.

              When using the upstream Linux kernel module, computation of  checksums  for  geneve
              and  vxlan  requires  Linux  kernel  version  4.0 or higher. gre and ip6gre support
              checksums for all versions of Open vSwitch that support GRE. The out of tree kernel
              module  distributed  as  part of OVS can compute all tunnel checksums on any kernel
              version that it is compatible with.

     Tunnel Options: IPsec:

       Setting any of these options enables IPsec support for a given tunnel. gre, geneve,  vxlan
       and  stt interfaces support these options. See the IPsec section in the Open_vSwitch table
       for a description of each mode.

       options : psk: optional string
              In PSK mode only, the preshared secret to negotiate tunnel. This value  must  match
              on both tunnel ends.

       options : remote_cert: optional string
              In  self-signed  certificate mode only, name of a PEM file containing a certificate
              of the remote switch. The certificate must be x.509 version 3 and with  the  string
              in common name (CN) also set in the subject alternative name (SAN).

       options : remote_name: optional string
              In CA-signed certificate mode only, common name (CN) of the remote certificate.

     Tunnel Options: erspan only:

       Only erspan interfaces support these options.

       options : erspan_idx: optional string
              20  bit  index/port  number  associated  with  the ERSPAN traffic’s source port and
              direction (ingress/egress). This field is platform dependent.

       options : erspan_ver: optional string
              ERSPAN version: 1 for version 1 (type II) or 2 for version 2 (type III).

       options : erspan_dir: optional string
              Specifies the ERSPAN v2 mirrored traffic’s direction. 1 for egress traffic,  and  0
              for ingress traffic.

       options : erspan_hwid: optional string
              ERSPAN  hardware  ID  is  a 6-bit unique identifier of an ERSPAN v2 engine within a
              system.

     Tunnel Options: Bareudp only:

       options : payload_type: optional string
              Specifies the ethertype of the l3 protocol the bareudp device  is  tunnelling.  For
              the  tunnels  which  supports  multiple ethertypes of a l3 protocol (IP, MPLS) this
              field specifies the protocol name as a string.

     Tunnel Options: srv6 only:

       options : srv6_segs: optional string
              Specifies the segment list in Segment Routing Header (SRH). It consists of a comma-
              separated    list    of    segments    represented    in    IPv6    format,    e.g.
              "fc00:100::1,fc00:200::1,fc00:300::1". Note that the first segment must be the same
              as options:remote_ip.

       options : srv6_flowlabel: optional string, one of compute, copy, or zero
              Optional. This option controls how flowlabel in outer IPv6 header is configured. It
              gives the benefit of IPv6 flow label based load balancing, which  is  supported  by
              some  popular  vendor appliances. Like net.ipv6.seg6_flowlabel sysconfig, it is one
              of the three values below:

              •      By default, or if this option is copy, copy  the  flowlabel  of  inner  IPv6
                     header  to  the flowlabel of outer IPv6 header. If inner header is not IPv6,
                     it is set to 0.

              •      If this option is zero, simply set flowlabel to 0.

              •      If this option is compute, set flowlabel to a hash over the L3/L4 fields  of
                     the inner packet.

     Patch Options:

       These  options  apply only to patch ports, that is, interfaces whose type column is patch.
       Patch ports are mainly a way to connect otherwise  independent  bridges  to  one  another,
       similar  to  how  one  might  plug an Ethernet cable (a ``patch cable’’) into two physical
       switches to connect those switches. The effect of plugging a patch port into two  switches
       is conceptually similar to that of plugging the two ends of a Linux veth device into those
       switches, but the implementation of patch ports makes them much more efficient.

       Patch ports may connect two different bridges (the usual case) or the same bridge. In  the
       latter  case, take special care to avoid loops, e.g. by programming appropriate flows with
       OpenFlow. Patch ports do not work if  its  ends  are  attached  to  bridges  on  different
       datapaths, e.g. to connect bridges in system and netdev datapaths.

       The  following command creates and connects patch ports p0 and p1 and adds them to bridges
       br0 and br1, respectively:

       ovs-vsctl add-port br0 p0 -- set Interface p0 type=patch options:peer=p1 \
              -- add-port br1 p1 -- set Interface p1 type=patch options:peer=p0

       options : peer: optional string
              The name of the Interface for the other side of the patch.  The  named  Interface’s
              own  peer  option  must  specify  this  Interface’s  name.  That  is, the two patch
              interfaces must have reversed name and peer values.

     PMD (Poll Mode Driver) Options:

       Only PMD netdevs support these options.

       options : n_rxq: optional string, containing an integer, at least 1
              Specifies the maximum number of rx queues to be created  for  PMD  netdev.  If  not
              specified or specified to 0, one rx queue will be created by default. Not supported
              by DPDK vHost interfaces.

       options : dpdk-devargs: optional string
              Specifies the PCI address associated with the port for  physical  devices,  or  the
              virtual  driver  to be used for the port when a virtual PMD is intended to be used.
              For the latter, the argument string typically takes the form  of  eth_driver_namex,
              where  driver_name  is  a  valid  virtual  DPDK  PMD  driver name and x is a unique
              identifier of your choice for the given port. Only supported by the dpdk port type.

       other_config : pmd-rxq-affinity: optional string
              Specifies mapping of RX queues of this interface to CPU cores.

              Value should be set in the following form:

              other_config:pmd-rxq-affinity=<rxq-affinity-list>

              where

              •      <rxq-affinity-list> ::= NULL | <non-empty-list>

              •      <non-empty-list> ::= <affinity-pair> | <affinity-pair> , <non-empty-list>

              •      <affinity-pair> ::= <queue-id> : <core-id>

       options : xdp-mode: optional string, one of best-effort, generic, native-with-zerocopy, or
       native
              Specifies the operational mode of the XDP program.

              In  native-with-zerocopy mode the XDP program is loaded into the device driver with
              zero-copy RX and TX enabled. This mode requires device driver support and  has  the
              best performance because there should be no copying of packets.

              native  is the same as native-with-zerocopy, but without zero-copy capability. This
              requires at least one copy  between  kernel  and  the  userspace.  This  mode  also
              requires support from device driver.

              In  generic  case  the  XDP  program  in kernel works after skb allocation on early
              stages of packet processing inside the network stack.  This  mode  doesn’t  require
              driver support, but has much lower performance.

              best-effort  tries to detect and choose the best (fastest) from the available modes
              for current interface.

              Note that this option is specific to netdev-afxdp. Defaults to best-effort mode.

       options : use-need-wakeup: optional string, either true or false
              Specifies whether to use need_wakeup feature  in  afxdp  netdev.  If  enabled,  OVS
              explicitly  wakes  up  the  kernel  RX, using poll() syscall and wakes up TX, using
              sendto() syscall. For physical devices, this feature improves  the  performance  by
              avoiding unnecessary sendto syscalls. Defaults to true if supported by libbpf.

       options : vhost-server-path: optional string
              The value specifies the path to the socket associated with a vHost User client mode
              device  that  has  been  or  will  be  created   by   QEMU.   Only   supported   by
              dpdkvhostuserclient interfaces.

       options : tx-retries-max: optional string, containing an integer, in range 0 to 32
              The  value  specifies the maximum amount of vhost tx retries that can be made while
              trying  to  send  a  batch  of  packets  to  an  interface.   Only   supported   by
              dpdkvhostuserclient interfaces.

              Default value is 8.

       options : n_rxq_desc: optional string, containing an integer, in range 1 to 4,096
              Specifies  the rx queue size (number rx descriptors) for dpdk ports. The value must
              be a power of 2, less than 4096 and supported by the hardware of the  device  being
              configured.  If  not  specified  or  an  incorrect  value  is  specified,  2048  rx
              descriptors will be used by default.

       options : n_txq_desc: optional string, containing an integer, in range 1 to 4,096
              Specifies the tx queue size (number tx descriptors) for dpdk ports. The value  must
              be  a  power of 2, less than 4096 and supported by the hardware of the device being
              configured.  If  not  specified  or  an  incorrect  value  is  specified,  2048  tx
              descriptors will be used by default.

       options : dpdk-vf-mac: optional string
              Ethernet  address  to  set  for  this  VF  interface. If unset then the default MAC
              address is used:

              •      For most drivers, the default MAC address assigned by their hardware.

              •      For bifurcated drivers, the MAC currently used by the kernel netdevice.

              This option may only be used with dpdk VF representors.

       options : rx-steering: optional string, either rss+lacp or rss
              Configure hardware Rx queue steering policy.

              This option takes one of the following values:

              rss    Distribution of ingress packets in  all  Rx  queues  according  to  the  RSS
                     algorithm. This is the default behaviour.

              rss+lacp
                     Distribution  of  ingress  packets according to the RSS algorithm on all but
                     the last Rx queue. An extra Rx queue is allocated for LACP packets.

              If the  user  has  already  configured  multiple  options:n_rxq  on  the  port,  an
              additional  one will be allocated for the specified protocols. Even if the hardware
              cannot satisfy the requested number of requested Rx queues, the last Rx queue  will
              be  used. If only one Rx queue is available or if the hardware does not support the
              rte_flow matchers/actions required  to  redirect  the  selected  protocols,  custom
              rx-steering will fall back to default rss mode.

              This  feature is mutually exclusive with other_config:hw-offload as it may conflict
              with the offloaded flows. If both  are  enabled,  rx-steering  will  fall  back  to
              default rss mode.

              This option is only applicable to interfaces with type dpdk.

       other_config : tx-steering: optional string, either hash or thread
              Specifies the Tx steering mode for the interface.

              thread  enables  static (1:1) thread-to-txq mapping when the number of Tx queues is
              greater than number of PMD threads, and dynamic (N:1) mapping if equal or lower. In
              this mode a single thread can not use more than 1 transmit queue of a given port.

              hash  enables  hash-based  Tx  steering,  which  distributes the packets on all the
              transmit queues based on their 5-tuples hashes.

              Defaults to thread.

     EMC (Exact Match Cache) Configuration:

       These settings controls behaviour of EMC lookups/insertions for packets received from  the
       interface.

       other_config : emc-enable: optional string, either true or false
              Specifies  if  Exact  Match  Cache  (EMC)  should  be used while processing packets
              received from this interface. If true, other_config:emc-insert-inv-prob  will  have
              effect on this interface.

              Defaults to true.

     MTU:

       The  MTU  (maximum  transmission  unit)  is the largest amount of data that can fit into a
       single Ethernet frame. The standard Ethernet MTU is 1500 bytes. Some  physical  media  and
       many kinds of virtual interfaces can be configured with higher MTUs.

       A  client may change an interface MTU by filling in mtu_request. Open vSwitch then reports
       in mtu the currently configured value.

       mtu: optional integer
              The currently configured MTU for the interface.

              This column will be empty for an interface that  does  not  have  an  MTU  as,  for
              example, some kinds of tunnels do not.

              Open  vSwitch  sets  this column’s value, so other clients should treat it as read-
              only.

       mtu_request: optional integer, at least 1
              Requested MTU (Maximum Transmission Unit) for the interface. A client can fill this
              column to change the MTU of an interface.

              RFC  791  requires  every  internet  module  to be able to forward a datagram of 68
              octets without further fragmentation. The maximum size of an  IP  packet  is  65535
              bytes.

              If this is not set and if the interface has internal type, Open vSwitch will change
              the MTU to match the minimum of the other interfaces in the bridge.

     Interface Status:

       Status information about interfaces attached to bridges, updated every 5 seconds. Not  all
       interfaces  have  all of these properties; virtual interfaces don’t have a link speed, for
       example. Non-applicable columns will have empty values.

       admin_state: optional string, either down or up
              The administrative state of the physical network link.

       link_state: optional string, either down or up
              The observed state of the physical network link.  This  is  ordinarily  the  link’s
              carrier status. If the interface’s Port is a bond configured for miimon monitoring,
              it is instead the network link’s miimon status.

       link_resets: optional integer
              The number of times Open vSwitch has observed  the  link_state  of  this  Interface
              change.

       link_speed: optional integer
              The  negotiated  speed  of  the  physical  network  link. Valid values are positive
              integers greater than 0.

       duplex: optional string, either full or half
              The duplex mode of the physical network link.

       lacp_current: optional boolean
              Boolean value indicating LACP status for this interface. If  true,  this  interface
              has  current  LACP information about its LACP partner. This information may be used
              to monitor the health of interfaces in a LACP enabled port.  This  column  will  be
              empty if LACP is not enabled.

       status: map of string-string pairs
              Key-value  pairs  that  report  port  status.  Supported  status  values  are type-
              dependent; some interfaces may not have a valid status:driver_name, for example.

       status : driver_name: optional string
              The name of the device driver controlling the network adapter.

       status : driver_version: optional string
              The version string of the device driver controlling the network adapter.

       status : firmware_version: optional string
              The version string of the network adapter’s firmware, if available.

       status : source_ip: optional string
              The source IP address used for an IPv4/IPv6 tunnel end-point, such as gre.

       status : tunnel_egress_iface: optional string
              Egress interface for tunnels. Currently only relevant for tunnels on Linux systems,
              this  column  will  show the name of the interface which is responsible for routing
              traffic destined for the configured options:remote_ip. This could  be  an  internal
              interface such as a bridge port.

       status : tunnel_egress_iface_carrier: optional string, either down or up
              Whether carrier is detected on status:tunnel_egress_iface.

     dpdk:

       DPDK specific interface status options.

       status : port_no: optional string
              DPDK port ID.

       status : numa_id: optional string
              NUMA socket ID to which an Ethernet device is connected.

       status : min_rx_bufsize: optional string
              Minimum size of RX buffer.

       status : max_rx_pktlen: optional string
              Maximum configurable length of RX pkt.

       status : max_rx_queues: optional string
              Maximum number of RX queues.

       status : max_tx_queues: optional string
              Maximum number of TX queues.

       status : max_mac_addrs: optional string
              Maximum number of MAC addresses.

       status : max_hash_mac_addrs: optional string
              Maximum number of hash MAC addresses for MTA and UTA.

       status : max_vfs: optional string
              Maximum number of hash MAC addresses for MTA and UTA. Maximum number of VFs.

       status : max_vmdq_pools: optional string
              Maximum number of VMDq pools.

       status : if_type: optional string
              Interface type ID according to IANA ifTYPE MIB definitions.

       status : if_descr: optional string
              Interface description string.

       status : bus_info: optional string
              Bus name and bus info such as Vendor ID and Device ID of PCI device.

       status : dpdk-vf-mac: optional string
              Ethernet address set for this VF interface. Only reported for dpdk VF representors.

       status : rx_steering: optional string
              Hardware Rx queue steering policy in use.

       status : rx_steering_queue: optional string
              ID of rx steering queue. Only reported if rx-steering is supported by hardware.

       status : rss_queues: optional string
              IDs of rss queues. Only reported if rx-steering is supported by hardware.

     dpdkvhostuser:

       dpdkvhostuser and dpdkvhostuserclient netdev specific interface status information.

       status : mode: optional string
              client (connecting) or server (listening) in the socket communication.

       status : features: optional string
              virtio features bitmap as per virtio specification.

       status : num_of_vrings: optional string
              The number of available virtqueues.

       status : numa: optional string
              The numa id of the device and guest memory.

       status : socket: optional string
              The path to the socket used for communication.

       status : status: optional string
              Status of connection to the device.

       status : vring_n_size: optional string
              Each  virtqueue  will have it’s size reported, where n is the virtqueue number from
              0..(num_of_vrings-1).

       status : userspace-tso: optional string
              Whether userspace-tso is enabled or disabled.

     Statistics:

       Key-value pairs that report interface statistics. The current implementation updates these
       counters  periodically.  The  update  period  is  controlled by other_config:stats-update-
       interval in the Open_vSwitch  table.  Future  implementations  may  update  them  when  an
       interface  is  created,  when they are queried (e.g. using an OVSDB select operation), and
       just before an interface is deleted due to virtual interface hot-unplug  or  VM  shutdown,
       and perhaps at other times, but not on any regular periodic basis.

       These are the same statistics reported by OpenFlow in its struct ofp_port_stats structure.
       If an interface does not support a given statistic, then that pair is omitted.

     Statistics: Successful transmit and receive counters:

       statistics : rx_packets: optional integer
              Number of received packets.

       statistics : rx_bytes: optional integer
              Number of received bytes.

       statistics : tx_packets: optional integer
              Number of transmitted packets.

       statistics : tx_bytes: optional integer
              Number of transmitted bytes.

     Statistics: Receive errors:

       statistics : rx_dropped: optional integer
              Number of packets dropped by RX.

       statistics : rx_frame_err: optional integer
              Number of frame alignment errors.

       statistics : rx_over_err: optional integer
              Number of packets with RX overrun.

       statistics : rx_crc_err: optional integer
              Number of CRC errors.

       statistics : rx_errors: optional integer
              Total number of receive errors, greater than or equal to the sum of the above.

     Statistics: Transmit errors:

       statistics : tx_dropped: optional integer
              Number of packets dropped by TX.

       statistics : collisions: optional integer
              Number of collisions.

       statistics : tx_errors: optional integer
              Total number of transmit errors, greater than or equal to the sum of the above.

     Ingress Policing:

       These settings control ingress policing for packets  received  on  this  interface.  On  a
       physical  interface, this limits the rate at which traffic is allowed into the system from
       the outside; on a virtual interface (one connected to a virtual machine), this limits  the
       rate at which the VM is able to transmit.

       Policing  is  a  simple  form  of quality-of-service that simply drops packets received in
       excess of the configured rate. Due to its simplicity, policing is  usually  less  accurate
       and less effective than egress QoS (which is configured using the QoS and Queue tables).

       Policing  settings  can  be  set with byte rate or packet rate, and they can be configured
       together, in which case they take effect together, that means the smaller speed  limit  of
       them is in effect.

       Currently, byte rate policing is implemented on Linux and OVS with DPDK, while packet rate
       policing is only implemented on Linux. Both Linux  and  OVS  DPDK  implementations  use  a
       simple ``token bucket’’ approach.

       Byte rate policing:

              •      The  size of the bucket corresponds to ingress_policing_burst. Initially the
                     bucket is full.

              •      Whenever a packet is received, its size (converted to tokens) is compared to
                     the  number  of  tokens  currently  in the bucket. If the required number of
                     tokens are  available,  they  are  removed  and  the  packet  is  forwarded.
                     Otherwise, the packet is dropped.

              •      Whenever  it  is  not  full,  the bucket is refilled with tokens at the rate
                     specified by ingress_policing_rate.

       Packet rate policing:

              •      The  size  of  the  bucket  corresponds   to   ingress_policing_kpkts_burst.
                     Initially the bucket is full.

              •      Whenever  a  packet  is received, it will consume one token from the current
                     bucket. If the token is available in the bucket, it’s removed and the packet
                     is forwarded. Otherwise, the packet is dropped.

              •      Whenever  it  is  not  full,  the bucket is refilled with tokens at the rate
                     specified by ingress_policing_kpkts_rate.

       Policing interacts badly with some network protocols, and especially  with  fragmented  IP
       packets. Suppose that there is enough network activity to keep the bucket nearly empty all
       the time. Then this token bucket algorithm will forward a single packet  every  so  often,
       with  the period depending on packet size and on the configured rate. All of the fragments
       of an IP packets are normally transmitted back-to-back, as a group. In such  a  situation,
       therefore,  only one of these fragments will be forwarded and the rest will be dropped. IP
       does not provide any way for  the  intended  recipient  to  ask  for  only  the  remaining
       fragments.  In  such  a case there are two likely possibilities for what will happen next:
       either all of the fragments will eventually be retransmitted (as TCP will  do),  in  which
       case  the same problem will recur, or the sender will not realize that its packet has been
       dropped and data will simply be lost (as some UDP-based protocols will do). Either way, it
       is possible that no forward progress will ever occur.

       ingress_policing_rate: integer, at least 0
              Maximum  rate  for  data  received on this interface, in kbps. Data received faster
              than this rate is dropped. Set to 0 (the default) to disable policing.

       ingress_policing_kpkts_rate: integer, at least 0
              Maximum rate for data received on this interface, in kpps (1  kpps  is  1000  pps).
              Data  received  faster than this rate is dropped. Set to 0 (the default) to disable
              policing.

       ingress_policing_burst: integer, at least 0
              Maximum burst size for data received on this interface, in kb.  The  default  burst
              size if set to 0 is 8000 kbit. This value has no effect if ingress_policing_rate is
              0.

              Specifying a larger burst size lets the  algorithm  be  more  forgiving,  which  is
              important  for protocols like TCP that react severely to dropped packets. The burst
              size should be at least the size of the interface’s MTU. Specifying a value that is
              numerically at least as large as 80% of ingress_policing_rate helps TCP come closer
              to achieving the full rate.

       ingress_policing_kpkts_burst: integer, at least 0
              Maximum burst size for data received on this interface, in kpkts (1 kpkts  is  1000
              packets).  The default burst size if set to 0 is 16 kpkts. This value has no effect
              if ingress_policing_kpkts_rate is 0.

              Specifying a larger burst size lets the  algorithm  be  more  forgiving,  which  is
              important for protocols like TCP that react severely to dropped packets. Specifying
              a value that is numerically at least as large as 80% of ingress_policing_kpkts_rate
              helps TCP come closer to achieving the full rate.

     Bidirectional Forwarding Detection (BFD):

       BFD,  defined  in  RFC  5880 and RFC 5881, allows point-to-point detection of connectivity
       failures by occasional transmission of BFD control messages. Open vSwitch  implements  BFD
       to serve as a more popular and standards compliant alternative to CFM.

       BFD  operates  by  regularly  transmitting  BFD  control  messages  at  a  rate negotiated
       independently in each direction. Each endpoint specifies the rate at which it  expects  to
       receive  control  messages,  and  the  rate  at  which  it is willing to transmit them. By
       default, Open vSwitch uses a detection multiplier  of  three,  meaning  that  an  endpoint
       signals  a connectivity fault if three consecutive BFD control messages fail to arrive. In
       the case of a unidirectional connectivity issue, the  system  not  receiving  BFD  control
       messages signals the problem to its peer in the messages it transmits.

       The  Open  vSwitch  implementation  of  BFD  aims  to  comply  faithfully  with  RFC  5880
       requirements. Open vSwitch does not implement the optional Authentication or ``Echo Mode’’
       features.

       OVS  2.13  and  earlier intercepted and processed all BFD packets. OVS 2.14 and later only
       intercept and process BFD packets destined to a configured BFD  instance,  and  other  BFD
       packets are made available to the OVS flow table for forwarding.

     BFD Configuration:

       A controller sets up key-value pairs in the bfd column to enable and configure BFD.

       bfd : enable: optional string, either true or false
              True  to enable BFD on this Interface. If not specified, BFD will not be enabled by
              default.

       bfd : min_rx: optional string, containing an integer, at least 1
              The shortest interval, in milliseconds, at which this BFD session offers to receive
              BFD  control  messages. The remote endpoint may choose to send messages at a slower
              rate. Defaults to 1000.

       bfd : min_tx: optional string, containing an integer, at least 1
              The shortest interval, in milliseconds, at which this BFD  session  is  willing  to
              transmit  BFD  control  messages. Messages will actually be transmitted at a slower
              rate if the remote endpoint is not willing to  receive  as  quickly  as  specified.
              Defaults to 100.

       bfd : decay_min_rx: optional string, containing an integer
              An  alternate receive interval, in milliseconds, that must be greater than or equal
              to bfd:min_rx. The implementation switches from bfd:min_rx to bfd:decay_min_rx when
              there  is  no obvious incoming data traffic at the interface, to reduce the CPU and
              bandwidth cost of monitoring an idle interface. This feature  may  be  disabled  by
              setting a value of 0. This feature is reset whenever bfd:decay_min_rx or bfd:min_rx
              changes.

       bfd : forwarding_if_rx: optional string, either true or false
              When true, traffic received on the Interface is used to indicate the capability  of
              packet  I/O.  BFD  control packets are still transmitted and received. At least one
              BFD control packet must  be  received  every  100  *  bfd:min_rx  amount  of  time.
              Otherwise, even if traffic are received, the bfd:forwarding will be false.

       bfd : cpath_down: optional string, either true or false
              Set  to  true to notify the remote endpoint that traffic should not be forwarded to
              this system for some reason other than a connectivty failure on the interface being
              monitored.  The  typical  underlying reason is ``concatenated path down,’’ that is,
              that connectivity beyond the local system is down. Defaults to false.

       bfd : check_tnl_key: optional string, either true or false
              Set to true to make BFD accept only control messages with a tunnel key of zero.  By
              default, BFD accepts control messages with any tunnel key.

       bfd : bfd_local_src_mac: optional string
              Set  to  an  Ethernet  address in the form xx:xx:xx:xx:xx:xx to set the MAC used as
              source for transmitted BFD packets. The default is  the  mac  address  of  the  BFD
              enabled interface.

       bfd : bfd_local_dst_mac: optional string
              Set  to  an  Ethernet  address in the form xx:xx:xx:xx:xx:xx to set the MAC used as
              destination for transmitted BFD packets. The default is 00:23:20:00:00:01.

       bfd : bfd_remote_dst_mac: optional string
              Set to an Ethernet address in the form xx:xx:xx:xx:xx:xx to set the  MAC  used  for
              checking   the   destination  of  received  BFD  packets.  Packets  with  different
              destination MAC will not be  considered  as  BFD  packets.  If  not  specified  the
              destination MAC address of received BFD packets are not checked.

       bfd : bfd_src_ip: optional string
              Set  to  an  IPv4  address to set the IP address used as source for transmitted BFD
              packets. The default is 169.254.1.1.

       bfd : bfd_dst_ip: optional string
              Set to an IPv4 address to set the IP address used as  destination  for  transmitted
              BFD packets. The default is 169.254.1.0.

       bfd : oam: optional string
              Some tunnel protocols (such as Geneve) include a bit in the header to indicate that
              the encapsulated packet is an OAM frame. By setting this to true, BFD packets  will
              be marked as OAM if encapsulated in one of these tunnels.

       bfd : mult: optional string, containing an integer, in range 1 to 255
              The  BFD  detection  multiplier,  which  defaults  to  3.  An  endpoint  signals  a
              connectivity fault if the given number of consecutive BFD control messages fail  to
              arrive.

     BFD Status:

       The  switch  sets  key-value pairs in the bfd_status column to report the status of BFD on
       this interface. When BFD is not enabled, with bfd:enable, the switch clears all  key-value
       pairs from bfd_status.

       bfd_status : state: optional string, one of admin_down, down, init, or up
              Reports  the  state  of  the  BFD  session.  The  BFD  session is fully healthy and
              negotiated if UP.

       bfd_status : forwarding: optional string, either true or false
              Reports whether the BFD session believes this Interface  may  be  used  to  forward
              traffic.  Typically  this  means  the local session is signaling UP, and the remote
              system isn’t signaling a problem such as concatenated path down.

       bfd_status : diagnostic: optional string
              A diagnostic code specifying the local system’s  reason  for  the  last  change  in
              session state. The error messages are defined in section 4.1 of [RFC 5880].

       bfd_status : remote_state: optional string, one of admin_down, down, init, or up
              Reports the state of the remote endpoint’s BFD session.

       bfd_status : remote_diagnostic: optional string
              A  diagnostic  code  specifying  the  remote system’s reason for the last change in
              session state. The error messages are defined in section 4.1 of [RFC 5880].

       bfd_status : flap_count: optional string, containing an integer, at least 0
              Counts the number of bfd_status:forwarding flaps since start. A flap is  considered
              as a change of the bfd_status:forwarding value.

     Connectivity Fault Management:

       802.1ag  Connectivity  Fault  Management  (CFM) allows a group of Maintenance Points (MPs)
       called a Maintenance Association (MA) to detect connectivity problems with each other. MPs
       within  a  MA  should  have  complete and exclusive interconnectivity. This is verified by
       occasionally broadcasting Continuity Check Messages (CCMs) at a configurable  transmission
       interval.

       According  to  the 802.1ag specification, each Maintenance Point should be configured out-
       of-band with a list of Remote Maintenance Points it  should  have  connectivity  to.  Open
       vSwitch differs from the specification in this area. It simply assumes the link is faulted
       if no Remote Maintenance Points are reachable, and considers it not faulted otherwise.

       When operating over tunnels which have no in_key, or an in_key  of  flow.  CFM  will  only
       accept CCMs with a tunnel key of zero.

       cfm_mpid: optional integer
              A   Maintenance  Point  ID  (MPID)  uniquely  identifies  each  endpoint  within  a
              Maintenance Association. The MPID is  used  to  identify  this  endpoint  to  other
              Maintenance  Points  in  the  MA.  Each end of a link being monitored should have a
              different MPID. Must be configured to enable CFM on this Interface.

              According to the 802.1ag specification, MPIDs can only  range  between  [1,  8191].
              However, extended mode (see other_config:cfm_extended) supports eight byte MPIDs.

       cfm_flap_count: optional integer
              Counts  the  number  of  cfm  fault flapps since boot. A flap is considered to be a
              change of the cfm_fault value.

       cfm_fault: optional boolean
              Indicates a connectivity fault triggered by an inability to receive heartbeats from
              any  remote  endpoint.  When  a  fault  is triggered on Interfaces participating in
              bonds, they will be disabled.

              Faults can be triggered for several reasons. Most importantly  they  are  triggered
              when  no  CCMs  are  received  for a period of 3.5 times the transmission interval.
              Faults are also triggered when any CCMs indicate that a Remote Maintenance Point is
              not receiving CCMs but able to send them. Finally, a fault is triggered if a CCM is
              received which indicates unexpected configuration. Notably, this case arises when a
              CCM is received which advertises the local MPID.

       cfm_fault_status : recv: none
              Indicates  a  CFM  fault  was  triggered  due  to  a  lack  of CCMs received on the
              Interface.

       cfm_fault_status : rdi: none
              Indicates a CFM fault was triggered due to the reception of a CCM with the RDI  bit
              flagged.  Endpoints  set the RDI bit in their CCMs when they are not receiving CCMs
              themselves. This typically indicates a unidirectional connectivity failure.

       cfm_fault_status : maid: none
              Indicates a CFM fault was triggered due to the reception of a CCM with a MAID other
              than  the  one  Open vSwitch uses. CFM broadcasts are tagged with an identification
              number in addition to  the  MPID  called  the  MAID.  Open  vSwitch  only  supports
              receiving CCM broadcasts tagged with the MAID it uses internally.

       cfm_fault_status : loopback: none
              Indicates  a  CFM fault was triggered due to the reception of a CCM advertising the
              same MPID configured in the cfm_mpid column of this Interface. This may indicate  a
              loop in the network.

       cfm_fault_status : overflow: none
              Indicates  a CFM fault was triggered because the CFM module received CCMs from more
              remote endpoints than it can keep track of.

       cfm_fault_status : override: none
              Indicates a  CFM  fault  was  manually  triggered  by  an  administrator  using  an
              ovs-appctl command.

       cfm_fault_status : interval: none
              Indicates  a  CFM fault was triggered due to the reception of a CCM frame having an
              invalid interval.

       cfm_remote_opstate: optional string, either down or up
              When in extended mode, indicates the operational state of the  remote  endpoint  as
              either up or down. See other_config:cfm_opstate.

       cfm_health: optional integer, in range 0 to 100
              Indicates  the  health of the interface as a percentage of CCM frames received over
              21 other_config:cfm_intervals. The health of an interface is  undefined  if  it  is
              communicating with more than one cfm_remote_mpids. It reduces if healthy heartbeats
              are not received at the expected rate, and gradually improves as healthy heartbeats
              are  received  at the desired rate. Every 21 other_config:cfm_intervals, the health
              of the interface is refreshed.

              As mentioned above, the faults can be  triggered  for  several  reasons.  The  link
              health will deteriorate even if heartbeats are received but they are reported to be
              unhealthy. An unhealthy heartbeat in this context is a heartbeat for  which  either
              some  fault  is  set or is out of sequence. The interface health can be 100 only on
              receiving healthy heartbeats at the desired rate.

       cfm_remote_mpids: set of integers
              When CFM is  properly  configured,  Open  vSwitch  will  occasionally  receive  CCM
              broadcasts. These broadcasts contain the MPID of the sending Maintenance Point. The
              list of MPIDs from which this Interface is receiving broadcasts from  is  regularly
              collected and written to this column.

       other_config : cfm_interval: optional string, containing an integer
              The  interval,  in  milliseconds,  between  transmissions  of CFM heartbeats. Three
              missed heartbeat receptions indicate a connectivity fault.

              In standard operation only intervals of 3,  10,  100,  1,000,  10,000,  60,000,  or
              600,000 ms are supported. Other values will be rounded down to the nearest value on
              the list. Extended mode (see other_config:cfm_extended) supports any interval up to
              65,535 ms. In either mode, the default is 1000 ms.

              We do not recommend using intervals less than 100 ms.

       other_config : cfm_extended: optional string, either true or false
              When  true,  the  CFM  module  operates  in  extended mode. This causes it to use a
              nonstandard destination address to avoid conflicting with compliant implementations
              which  may  be  running  concurrently  on  the  network. Furthermore, extended mode
              increases the accuracy of the cfm_interval configuration parameter by breaking wire
              compatibility  with  802.1ag  compliant  implementations.  And extended mode allows
              eight byte MPIDs. Defaults to false.

       other_config : cfm_demand: optional string, either true or false
              When true, and other_config:cfm_extended is true, the CFM module operates in demand
              mode.  When  in  demand mode, traffic received on the Interface is used to indicate
              liveness. CCMs are still transmitted  and  received.  At  least  one  CCM  must  be
              received  every  100 * other_config:cfm_interval amount of time. Otherwise, even if
              traffic are received, the CFM module will raise the connectivity fault.

              Demand mode has a couple of caveats:

              •      To ensure that ovs-vswitchd has enough time  to  pull  statistics  from  the
                     datapath,    the    fault    detection    interval   is   set   to   3.5   *
                     MAX(other_config:cfm_interval, 500) ms.

              •      To avoid ambiguity, demand mode disables  itself  when  there  are  multiple
                     remote maintenance points.

              •      If    the    Interface   is   heavily   congested,   CCMs   containing   the
                     other_config:cfm_opstate status  may  be  dropped  causing  changes  in  the
                     operational  state  to be delayed. Similarly, if CCMs containing the RDI bit
                     are not received, unidirectional link failures may not be detected.

       other_config : cfm_opstate: optional string, either down or up
              When down, the CFM module marks all CCMs it generates as operationally down without
              triggering  a fault. This allows remote maintenance points to choose not to forward
              traffic to the Interface on which this CFM module is running.  Currently,  in  Open
              vSwitch,  the opdown bit of CCMs affects Interfaces participating in bonds, and the
              bundle OpenFlow action. This setting is ignored when CFM is not in  extended  mode.
              Defaults to up.

       other_config : cfm_ccm_vlan: optional string, containing an integer, in range 1 to 4,095
              When  set,  the  CFM module will apply a VLAN tag to all CCMs it generates with the
              given value. May be the string random in which case each CCM will be tagged with  a
              different randomly generated VLAN.

       other_config : cfm_ccm_pcp: optional string, containing an integer, in range 1 to 7
              When  set,  the  CFM module will apply a VLAN tag to all CCMs it generates with the
              given  PCP  value,  the  VLAN  ID  of  the  tag  is  governed  by  the   value   of
              other_config:cfm_ccm_vlan. If other_config:cfm_ccm_vlan is unset, a VLAN ID of zero
              is used.

     Bonding Configuration:

       other_config : lacp-port-id: optional string, containing an integer, in range 1 to 65,535
              The LACP port ID of this Interface. Port IDs  are  used  in  LACP  negotiations  to
              identify individual ports participating in a bond.

       other_config  :  lacp-port-priority: optional string, containing an integer, in range 1 to
       65,535
              The LACP port priority of this Interface.  In  LACP  negotiations  Interfaces  with
              numerically lower priorities are preferred for aggregation.

       other_config : lacp-aggregation-key: optional string, containing an integer, in range 1 to
       65,535
              The LACP aggregation key of this Interface. Interfaces with  different  aggregation
              keys may not be active within a given Port at the same time.

     Virtual Machine Identifiers:

       These  key-value  pairs  specifically  apply  to  an  interface  that represents a virtual
       Ethernet interface connected to a virtual machine. These key-value  pairs  should  not  be
       present  for  other  types  of  interfaces. Keys whose names end in -uuid have values that
       uniquely identify the entity in question.

       external_ids : attached-mac: optional string
              The MAC address programmed into the ``virtual hardware’’ for this interface, in the
              form xx:xx:xx:xx:xx:xx.

       external_ids : iface-id: optional string
              A system-unique identifier for the interface.

       external_ids : iface-status: optional string, either active or inactive
              Hypervisors  may  sometimes  have  more  than one interface associated with a given
              external_ids:iface-id, only one of which is actually in use at a  given  time.  For
              example,  in  some  circumstances  hypervisor may have both a ``tap’’ and a ``vif’’
              interface for a single external_ids:iface-id, but only uses one of them at a  time.
              A  hypervisor that behaves this way must mark the currently in use interface active
              and the others inactive. A hypervisor that never has more than one interface for  a
              given    external_ids:iface-id   may   mark   that   interface   active   or   omit
              external_ids:iface-status entirely.

              During VM migration, a given  external_ids:iface-id  might  transiently  be  marked
              active   on   two   different   hypervisors.   That  is,  active  means  that  this
              external_ids:iface-id is the active instance within a single hypervisor, not  in  a
              broader  scope. There is one exception: some hypervisors support ``migration’’ from
              a given hypervisor to  itself  (most  often  for  test  purposes).  During  such  a
              ``migration,’’  two  instances  of  a  single  external_ids:iface-id  might both be
              briefly marked active on a single hypervisor.

       external_ids : vm-id: optional string
              The VM to which this interface belongs.

     Auto Attach Configuration:

       Auto Attach configuration for a particular interface.

       lldp : enable: optional string, either true or false
              True to enable LLDP on this Interface. If not specified, LLDP will be  disabled  by
              default.

     Flow control Configuration:

       Ethernet  flow control defined in IEEE 802.1Qbb provides link level flow control using MAC
       pause frames. Implemented only for interfaces with type dpdk.

       options : rx-flow-ctrl: optional string, either true or false
              Set to true to enable Rx flow control  on  physical  ports.  By  default,  Rx  flow
              control is disabled.

       options : tx-flow-ctrl: optional string, either true or false
              Set  to  true  to  enable  Tx  flow  control on physical ports. By default, Tx flow
              control is disabled.

       options : flow-ctrl-autoneg: optional string, either true or false
              Set to true to enable flow control auto negotiation on physical ports. By  default,
              auto-neg is disabled.

     Link State Change detection mode:

       options : dpdk-lsc-interrupt: optional string, either true or false
              Set  this  value  to  true  to configure interrupt mode for Link State Change (LSC)
              detection instead of poll mode for the DPDK interface.

              If this value is not set, poll mode is configured.

              This parameter has an effect only on netdev dpdk interfaces.

     Common Columns:

       The overall purpose of these columns is described under Common Columns at the beginning of
       this document.

       other_config: map of string-string pairs

       external_ids: map of string-string pairs

Flow_Table TABLE

       Configuration for a particular OpenFlow table.

   Summary:
       name                          optional string
       Eviction Policy:
         flow_limit                  optional integer, at least 0
         overflow_policy             optional string, either evict or refuse
         groups                      set of strings
       Classifier Optimization:
         prefixes                    set of up to 3 strings
       Common Columns:
         external_ids                map of string-string pairs

   Details:
       name: optional string
              The  table’s name. Set this column to change the name that controllers will receive
              when they request table statistics, e.g. ovs-ofctl dump-tables. The name  does  not
              affect switch behavior.

     Eviction Policy:

       Open  vSwitch supports limiting the number of flows that may be installed in a flow table,
       via the flow_limit column. When adding a flow would exceed this  limit,  by  default  Open
       vSwitch  reports  an  error,  but  there are two ways to configure Open vSwitch to instead
       delete (``evict’’) a flow to make room for the new one:

              •      Set the overflow_policy column to evict.

              •      Send an OpenFlow 1.4+ ``table mod request’’ to enable eviction for the  flow
                     table (e.g. ovs-ofctl -O OpenFlow14 mod-table br0 0 evict to enable eviction
                     on flow table 0 of bridge br0).

       When a flow must be evicted due to overflow, the  flow  to  evict  is  chosen  through  an
       approximation  of  the  following  algorithm.  This  algorithm  is  used regardless of how
       eviction was enabled:

              1.  Divide the flows in the table into groups based on the values of the fields  or
                  subfields  specified  in the groups column, so that all of the flows in a given
                  group have the same values for those fields. If a flow does not specify a given
                  field,  that field’s value is treated as 0. If groups is empty, then all of the
                  flows in the flow table are treated as a single group.

              2.  Consider the flows in the largest group, that is, the group that  contains  the
                  greatest  number  of  flows.  If  two  or more groups all have the same largest
                  number of flows, consider the flows in all of those groups.

              3.  If the flows under consideration have different  importance  values,  eliminate
                  from   consideration  any  flows  except  those  with  the  lowest  importance.
                  (``Importance,’’ a 16-bit integer value attached to each flow,  was  introduced
                  in  OpenFlow 1.4. Flows inserted with older versions of OpenFlow always have an
                  importance of 0.)

              4.  Among the flows under consideration, choose the flow that expires  soonest  for
                  eviction.

       The  eviction  process  only  considers flows that have an idle timeout or a hard timeout.
       That is, eviction never  deletes  permanent  flows.  (Permanent  flows  do  count  against
       flow_limit.)

       flow_limit: optional integer, at least 0
              If set, limits the number of flows that may be added to the table. Open vSwitch may
              limit the number of flows in a table  for  other  reasons,  e.g.  due  to  hardware
              limitations or for resource availability or performance reasons.

       overflow_policy: optional string, either evict or refuse
              Controls  the  switch’s  behavior  when an OpenFlow flow table modification request
              would add flows in excess of flow_limit. The supported values are:

              refuse Refuse to add the flow or flows.  This  is  also  the  default  policy  when
                     overflow_policy is unset.

              evict  Delete a flow chosen according to the algorithm described above.

       groups: set of strings
              When overflow_policy is evict, this controls how flows are chosen for eviction when
              the flow table would otherwise exceed flow_limit flows. Its value is a set  of  NXM
              fields   or   sub-fields,  each  of  which  takes  one  of  the  forms  field[]  or
              field[start..end], e.g. NXM_OF_IN_PORT[]. Please see  meta-flow.h  for  a  complete
              list of NXM field names.

              Open vSwitch ignores any invalid or unknown field specifications.

              When  eviction  is  not  enabled,  via  overflow_policy or an OpenFlow 1.4+ ``table
              mod,’’ this column has no effect.

     Classifier Optimization:

       prefixes: set of up to 3 strings
              This string set specifies which fields should be used for address prefix  tracking.
              Prefix  tracking  allows  the  classifier  to skip rules with longer than necessary
              prefixes, resulting in better wildcarding for datapath flows.

              Prefix tracking may be beneficial when a flow table contains matches on IP  address
              fields  with  different  prefix lengths. For example, when a flow table contains IP
              address matches on both full  addresses  and  proper  prefixes,  the  full  address
              matches  will  typically  cause  the datapath flow to un-wildcard the whole address
              field (depending on flow entry  priorities).  In  this  case  each  packet  with  a
              different  address  gets  handed to the userspace for flow processing and generates
              its own datapath flow. With prefix  tracking  enabled  for  the  address  field  in
              question  packets  with addresses matching shorter prefixes would generate datapath
              flows where the irrelevant address bits are wildcarded, allowing the same  datapath
              flow  to  handle  all  the packets within the prefix in question. In this case many
              userspace upcalls can be avoided and the overall performance can be better.

              This is a performance optimization only, so packets will receive the same treatment
              with or without prefix tracking.

              The  supported  fields  are:  tun_id, tun_src, tun_dst, tun_ipv6_src, tun_ipv6_dst,
              nw_src, nw_dst (or aliases ip_src and ip_dst), ipv6_src, and ipv6_dst. (Using  this
              feature  for  tun_id  would only make sense if the tunnel IDs have prefix structure
              similar to IP addresses.)

              By default, the prefixes=ip_dst,ip_src are used on each flow table. This  instructs
              the  flow  classifier  to track the IP destination and source addresses used by the
              rules in this specific flow table.

              The keyword none is recognized as an  explicit  override  of  the  default  values,
              causing no prefix fields to be tracked.

              To set the prefix fields, the flow table record needs to exist:

              ovs-vsctl   set   Bridge   br0  flow_tables:0=@N1  --  --id=@N1  create  Flow_Table
              name=table0
                     Creates a flow table record for the OpenFlow table number 0.

              ovs-vsctl set Flow_Table table0 prefixes=ip_dst,ip_src
                     Enables prefix tracking for IP source and destination address fields.

              There is a maximum number of fields that can be enabled for  any  one  flow  table.
              Currently this limit is 3.

     Common Columns:

       The overall purpose of these columns is described under Common Columns at the beginning of
       this document.

       external_ids: map of string-string pairs

QoS TABLE

       Quality of Service (QoS) configuration for each Port that references it.

   Summary:
       type                          string
       queues                        map of integer-Queue pairs, key in range 0 to 4,294,967,295
       Configuration for linux-htb and linux-hfsc:
         other_config : max-rate     optional string, containing an integer
       Configuration for egress-policer QoS:
         other_config : cir          optional string, containing an integer
         other_config : cbs          optional string, containing an integer
         other_config : eir          optional string, containing an integer
         other_config : ebs          optional string, containing an integer
       Configuration for linux-sfq:
         other_config : perturb      optional string, containing an integer
         other_config : quantum      optional string, containing an integer
       Configuration for linux-netem:
         other_config : latency      optional string, containing an integer
         other_config : limit        optional string, containing an integer
         other_config : loss         optional string, containing an integer
         other_config : jitter       optional string, containing an integer
       Common Columns:
         other_config                map of string-string pairs
         external_ids                map of string-string pairs

   Details:
       type: string
              The type of QoS to implement. The currently defined types are listed below:

              linux-htb
                     Linux  ``hierarchy  token  bucket’’  classifier.  See  tc-htb(8)  (also   at
                     http://linux.die.net/man/8/tc-htb)       and       the       HTB      manual
                     (http://luxik.cdi.cz/~devik/qos/htb/manual/userg.htm) for information on how
                     this classifier works and how to configure it.

              linux-hfsc
                     Linux     "Hierarchical     Fair     Service    Curve"    classifier.    See
                     http://linux-ip.net/articles/hfsc.en/ for information on how this classifier
                     works.

              linux-sfq
                     Linux  ``Stochastic  Fairness  Queueing’’ classifier. See tc-sfq(8) (also at
                     http://linux.die.net/man/8/tc-sfq) for information on  how  this  classifier
                     works.

              linux-codel
                     Linux   ``Controlled   Delay’’   classifier.   See   tc-codel(8)   (also  at
                     http://man7.org/linux/man-pages/man8/tc-codel.8.html) for information on how
                     this classifier works.

              linux-fq_codel
                     Linux  ``Fair Queuing with Controlled Delay’’ classifier. See tc-fq_codel(8)
                     (also   at   http://man7.org/linux/man-pages/man8/tc-fq_codel.8.html)    for
                     information on how this classifier works.

              linux-netem
                     Linux   ``Network   Emulator’’   classifier.   See   tc-netem(8)   (also  at
                     http://man7.org/linux/man-pages/man8/tc-netem.8.html) for information on how
                     this classifier works.

              linux-noop
                     Linux  ``No operation.’’ By default, Open vSwitch manages quality of service
                     on all  of  its  configured  ports.  This  can  be  helpful,  but  sometimes
                     administrators  prefer  to  use  other  software  to  manage  QoS. This type
                     prevents Open vSwitch from changing the QoS configuration for a port.

              egress-policer
                     A DPDK egress policer  algorithm  using  the  DPDK  rte_meter  library.  The
                     rte_meter  library  provides an implementation which allows the metering and
                     policing of traffic. The implementation in OVS essentially creates a  single
                     token  bucket  used  to  police  traffic.  It  should be noted that when the
                     rte_meter is configured as part of QoS there will be a performance  overhead
                     as  the rte_meter itself will consume CPU cycles in order to police traffic.
                     These CPU cycles ordinarily are used for packet  proccessing.  As  such  the
                     drop  in  performance  will be noticed in terms of overall aggregate traffic
                     throughput.

              trtcm-policer
                     A DPDK egress policer  algorithm  using  RFC  4115’s  Two-Rate,  Three-Color
                     marker. It’s a two-level hierarchical policer which first does a color-blind
                     marking of the traffic at the queue level, followed by a color-aware marking
                     at  the  port  level.  At  the  end  traffic  marked  as  Green or Yellow is
                     forwarded, Red is dropped. For details on how traffic  is  marked,  see  RFC
                     4115.  If  the  ``default  queue’’,  0, is not configured it’s automatically
                     created with the same other_config values as the physical port.

       queues: map of integer-Queue pairs, key in range 0 to 4,294,967,295
              A map from queue numbers to Queue records. The supported  range  of  queue  numbers
              depend  on type. The queue numbers are the same as the queue_id used in OpenFlow in
              struct ofp_action_enqueue and other structures.

              Queue 0 is the ``default queue.’’ It is used by OpenFlow  output  actions  when  no
              specific  queue  has  been set. When no configuration for queue 0 is present, it is
              automatically configured as if a Queue record  with  empty  dscp  and  other_config
              columns  had  been specified. (Before version 1.6, Open vSwitch would leave queue 0
              unconfigured in this case. With some queuing disciplines, this dropped all  packets
              destined for the default queue.)

     Configuration for linux-htb and linux-hfsc:

       The linux-htb and linux-hfsc classes support the following key-value pair:

       other_config : max-rate: optional string, containing an integer
              Maximum  rate  shared  by all queued traffic, in bit/s. Optional. If not specified,
              for physical interfaces, the default is the link rate. For other interfaces  or  if
              the link rate cannot be determined, the default is currently 10 Gbps.

     Configuration for egress-policer QoS:

       QoS  type  egress-policer  provides egress policing for userspace port types with DPDK. It
       has the following key-value pairs defined.

       other_config : cir: optional string, containing an integer
              The Committed Information Rate (CIR) is measured in bytes of IP packets per second,
              i.e. it includes the IP header, but not link specific (e.g. Ethernet) headers. This
              represents the bytes per second rate at which the token bucket will be updated. The
              cir  value  is  calculated by (pps x packet data size). For example assuming a user
              wishes to limit a stream consisting of 64 byte packets to  1  million  packets  per
              second  the  CIR  would  be  set  to  to to 46000000. This value can be broken into
              ’1,000,000 x 46’. Where 1,000,000 is the policing rate for the  number  of  packets
              per  second  and 46 represents the size of the packet data for a 64 bytes IP packet
              without 14 bytes Ethernet and 4 bytes FCS header.

       other_config : cbs: optional string, containing an integer
              The Committed Burst Size (CBS) is measured in bytes and represents a token  bucket.
              At a minimum this value should be be set to the expected largest size packet in the
              traffic stream. In practice larger values may be used to increase the size  of  the
              token  bucket.  If  a packet can be transmitted then the cbs will be decremented by
              the number of bytes/tokens of the packet. If there are not enough tokens in the cbs
              bucket the packet will be dropped.

       other_config : eir: optional string, containing an integer
              The  Excess  Information  Rate (EIR) is measured in bytes of IP packets per second,
              i.e. it includes the IP header, but not link specific (e.g. Ethernet) headers. This
              represents the bytes per second rate at which the token bucket will be updated. The
              eir value is calculated by (pps x packet data size). For example  assuming  a  user
              wishes  to  limit  a  stream consisting of 64 byte packets to 1 million packets per
              second the EIR would be set to to to  46000000.  This  value  can  be  broken  into
              ’1,000,000  x  46’.  Where 1,000,000 is the policing rate for the number of packets
              per second and 46 represents the size of the packet data for a 64 bytes  IP  packet
              without 14 bytes Ethernet and 4 bytes FCS header.

       other_config : ebs: optional string, containing an integer
              The  Excess Burst Size (EBS) is measured in bytes and represents a token bucket. At
              a minimum this value should be be set to the expected largest size  packet  in  the
              traffic  stream.  In practice larger values may be used to increase the size of the
              token bucket. If a packet can be transmitted then the ebs will  be  decremented  by
              the number of bytes/tokens of the packet. If there are not enough tokens in the cbs
              bucket the packet might be dropped.

     Configuration for linux-sfq:

       The linux-sfq QoS supports the following key-value pairs:

       other_config : perturb: optional string, containing an integer
              Number of seconds between consecutive perturbations in hashing algorithm. Different
              flows can end up in the same hash bucket causing unfairness. Perturbation’s goal is
              to remove possible unfairness. The default and recommended value is 10. Too  low  a
              value is discouraged because each perturbation can cause packet reordering.

       other_config : quantum: optional string, containing an integer
              Number of bytes linux-sfq QoS can dequeue in one turn in round-robin from one flow.
              The default and recommended value is equal to interface’s MTU.

     Configuration for linux-netem:

       The linux-netem QoS supports the following key-value pairs:

       other_config : latency: optional string, containing an integer
              Adds the chosen delay to the packets outgoing  to  chosen  network  interface.  The
              latency value expressed in us.

       other_config : limit: optional string, containing an integer
              Maximum number of packets the qdisc may hold queued at a time. The default value is
              1000.

       other_config : loss: optional string, containing an integer
              Adds an independent loss probability  to  the  packets  outgoing  from  the  chosen
              network interface.

       other_config : jitter: optional string, containing an integer
              Adds  the  provided jitter to the latency outgoing to the chosen network interface.
              The jitter value expressed in us.

     Common Columns:

       The overall purpose of these columns is described under Common Columns at the beginning of
       this document.

       other_config: map of string-string pairs

       external_ids: map of string-string pairs

Queue TABLE

       A  configuration  for  a  port  output queue, used in configuring Quality of Service (QoS)
       features. May be referenced by queues column in QoS table.

   Summary:
       dscp                          optional integer, in range 0 to 63
       Configuration for linux-htb QoS:
         other_config : min-rate     optional string, containing an integer, at least 1
         other_config : max-rate     optional string, containing an integer, at least 1
         other_config : burst        optional string, containing an integer, at least 1
         other_config : priority     optional string,  containing  an  integer,  in  range  0  to
                                     4,294,967,295
       Configuration for linux-hfsc QoS:
         other_config : min-rate     optional string, containing an integer, at least 1
         other_config : max-rate     optional string, containing an integer, at least 1
       Common Columns:
         other_config                map of string-string pairs
         external_ids                map of string-string pairs

   Details:
       dscp: optional integer, in range 0 to 63
              If set, Open vSwitch will mark all traffic egressing this Queue with the given DSCP
              bits. Traffic egressing the default Queue is  only  marked  if  it  was  explicitly
              selected as the Queue at the time the packet was output. If unset, the DSCP bits of
              traffic egressing this Queue will remain unchanged.

     Configuration for linux-htb QoS:

       QoS type linux-htb may use queue_ids less than 61440. It has the following key-value pairs
       defined.

       other_config : min-rate: optional string, containing an integer, at least 1
              Minimum guaranteed bandwidth, in bit/s.

       other_config : max-rate: optional string, containing an integer, at least 1
              Maximum  allowed bandwidth, in bit/s. Optional. If specified, the queue’s rate will
              not be allowed  to  exceed  the  specified  value,  even  if  excess  bandwidth  is
              available. If unspecified, defaults to no limit.

       other_config : burst: optional string, containing an integer, at least 1
              Burst  size,  in  bits.  This is the maximum amount of ``credits’’ that a queue can
              accumulate while it is idle. Optional.  Details  of  the  linux-htb  implementation
              require a minimum burst size, so a too-small burst will be silently ignored.

       other_config   :  priority:  optional  string,  containing  an  integer,  in  range  0  to
       4,294,967,295
              A queue with a smaller priority will receive all the excess bandwidth that  it  can
              use  before  a queue with a larger value receives any. Specific priority values are
              unimportant; only relative ordering matters. Defaults to 0 if unspecified.

     Configuration for linux-hfsc QoS:

       QoS type linux-hfsc may use queue_ids less than 61440.  It  has  the  following  key-value
       pairs defined.

       other_config : min-rate: optional string, containing an integer, at least 1
              Minimum guaranteed bandwidth, in bit/s.

       other_config : max-rate: optional string, containing an integer, at least 1
              Maximum  allowed bandwidth, in bit/s. Optional. If specified, the queue’s rate will
              not be allowed  to  exceed  the  specified  value,  even  if  excess  bandwidth  is
              available. If unspecified, defaults to no limit.

     Common Columns:

       The overall purpose of these columns is described under Common Columns at the beginning of
       this document.

       other_config: map of string-string pairs

       external_ids: map of string-string pairs

Mirror TABLE

       A port mirror within a Bridge.

       A port mirror configures a bridge to send selected frames to special  ``mirrored’’  ports,
       in  addition  to  their  normal destinations. Mirroring traffic may also be referred to as
       SPAN or RSPAN, depending on how the mirrored traffic is sent.

       When a packet enters an Open vSwitch bridge, it becomes eligible for  mirroring  based  on
       its  ingress port and VLAN. As the packet travels through the flow tables, each time it is
       output to a port, it becomes eligible for mirroring based on the egress port and VLAN.  In
       Open  vSwitch  2.5 and later, mirroring occurs just after a packet first becomes eligible,
       using the packet as it exists at that point; in Open vSwitch 2.4  and  earlier,  mirroring
       occurs only after a packet has traversed all the flow tables, using the original packet as
       it entered the bridge. This makes a difference only  when  the  flow  table  modifies  the
       packet:  in  Open  vSwitch 2.4, the modifications are never visible to mirrors, whereas in
       Open vSwitch 2.5 and later modifications made  before  the  first  output  that  makes  it
       eligible for mirroring to a particular destination are visible.

       A  packet  that enters an Open vSwitch bridge is mirrored to a particular destination only
       once, even if it is eligible for multiple reasons. For example, a packet would be mirrored
       to  a  particular output_port only once, even if it is selected for mirroring to that port
       by select_dst_port and select_src_port in the same or different Mirror records.

   Summary:
       name                          string
       Selecting Packets for Mirroring:
         select_all                  boolean
         select_dst_port             set of weak reference to Ports
         select_src_port             set of weak reference to Ports
         select_vlan                 set of up to 4,096 integers, in range 0 to 4,095
       Mirroring Destination Configuration:
         output_port                 optional weak reference to Port
         output_vlan                 optional integer, in range 1 to 4,095
         snaplen                     optional integer, in range 14 to 65,535
       Statistics: Mirror counters:
         statistics : tx_packets     optional integer
         statistics : tx_bytes       optional integer
       Common Columns:
         external_ids                map of string-string pairs

   Details:
       name: string
              Arbitrary identifier for the Mirror.

     Selecting Packets for Mirroring:

       To be selected for mirroring, a given packet must enter or  leave  the  bridge  through  a
       selected port and it must also be in one of the selected VLANs.

       select_all: boolean
              If true, every packet arriving or departing on any port is selected for mirroring.

       select_dst_port: set of weak reference to Ports
              Ports on which departing packets are selected for mirroring.

       select_src_port: set of weak reference to Ports
              Ports on which arriving packets are selected for mirroring.

       select_vlan: set of up to 4,096 integers, in range 0 to 4,095
              VLANs  on which packets are selected for mirroring. An empty set selects packets on
              all VLANs.

     Mirroring Destination Configuration:

       These columns are mutually exclusive. Exactly one of them must be nonempty.

       output_port: optional weak reference to Port
              Output port for selected packets, if nonempty.

              Specifying a port for mirror output reserves that port exclusively  for  mirroring.
              No frames other than those selected for mirroring via this column will be forwarded
              to the port, and any frames received on the port will be discarded.

              The output port may be any kind of port supported by Open vSwitch. It may  be,  for
              example, a physical port (sometimes called SPAN) or a GRE tunnel.

       output_vlan: optional integer, in range 1 to 4,095
              Output VLAN for selected packets, if nonempty.

              The  frames will be sent out all ports that trunk output_vlan, as well as any ports
              with implicit VLAN output_vlan. When a mirrored frame is sent out a trunk port, the
              frame’s VLAN tag will be set to output_vlan, replacing any existing tag; when it is
              sent out an implicit VLAN port,  the  frame  will  not  be  tagged.  This  type  of
              mirroring is sometimes called RSPAN.

              See  the  documentation  for other_config:forward-bpdu in the Interface table for a
              list of destination MAC addresses which will not be mirrored to  a  VLAN  to  avoid
              confusing switches that interpret the protocols that they represent.

              Please  note:  Mirroring  to  a  VLAN can disrupt a network that contains unmanaged
              switches. Consider an unmanaged physical switch with two ports: port  1,  connected
              to  an  end  host,  and  port  2, connected to an Open vSwitch configured to mirror
              received packets into VLAN 123 on port 2. Suppose that the end host sends a  packet
              on  port  1  that the physical switch forwards to port 2. The Open vSwitch forwards
              this packet to its destination and then reflects it back on port  2  in  VLAN  123.
              This  reflected  packet  causes  the  unmanaged  physical switch to replace the MAC
              learning table entry, which correctly pointed to port 1, with one that  incorrectly
              points  to  port 2. Afterward, the physical switch will direct packets destined for
              the end host to the Open vSwitch on port 2, instead of to the end host on  port  1,
              disrupting  connectivity.  If mirroring to a VLAN is desired in this scenario, then
              the physical switch must be replaced by one that learns  Ethernet  addresses  on  a
              per-VLAN  basis.  In  addition,  learning should be disabled on the VLAN containing
              mirrored traffic. If this is not done then intermediate switches will learn the MAC
              address  of  each end host from the mirrored traffic. If packets being sent to that
              end host are also mirrored, then they will be dropped since the switch will attempt
              to  send  them  out  the input port. Disabling learning for the VLAN will cause the
              switch to correctly send the packet out all ports configured for that VLAN. If Open
              vSwitch is being used as an intermediate switch, learning can be disabled by adding
              the mirrored VLAN to flood_vlans in the appropriate Bridge table or tables.

              Mirroring to a GRE tunnel has fewer caveats than mirroring to  a  VLAN  and  should
              generally be preferred.

       snaplen: optional integer, in range 14 to 65,535
              Maximum per-packet number of bytes to mirror.

              A  mirrored  packet  with size larger than snaplen will be truncated in datapath to
              snaplen bytes before sending to the mirror output port. If omitted, packets are not
              truncated.

     Statistics: Mirror counters:

       Key-value  pairs  that  report  mirror  statistics.  The  update  period  is controlled by
       other_config:stats-update-interval in the Open_vSwitch table.

       statistics : tx_packets: optional integer
              Number of packets transmitted through this mirror.

       statistics : tx_bytes: optional integer
              Number of bytes transmitted through this mirror.

     Common Columns:

       The overall purpose of these columns is described under Common Columns at the beginning of
       this document.

       external_ids: map of string-string pairs

Controller TABLE

       An OpenFlow controller.

   Summary:
       Core Features:
         type                        optional string, either primary or service
         target                      string
         connection_mode             optional string, either in-band or out-of-band
       Controller Failure Detection and Handling:
         max_backoff                 optional integer, at least 1,000
         inactivity_probe            optional integer
       Asynchronous Messages:
         enable_async_messages       optional boolean
         Controller Rate Limiting:
            controller_queue_size    optional integer, in range 1 to 512
            controller_rate_limit    optional integer, at least 100
            controller_burst_limit   optional integer, at least 25
            Controller Rate Limiting Statistics:
              status : packet-in-TYPE-bypassed
                                     optional string, containing an integer, at least 0
              status : packet-in-TYPE-queued
                                     optional string, containing an integer, at least 0
              status : packet-in-TYPE-dropped
                                     optional string, containing an integer, at least 0
              status : packet-in-TYPE-backlog
                                     optional string, containing an integer, at least 0
       Additional In-Band Configuration:
         local_ip                    optional string
         local_netmask               optional string
         local_gateway               optional string
       Controller Status:
         is_connected                boolean
         role                        optional string, one of master, other, or slave
         status : last_error         optional string
         status : state              optional  string,  one of ACTIVE, BACKOFF, CONNECTING, IDLE,
                                     or VOID
         status : sec_since_connect  optional string, containing an integer, at least 0
         status : sec_since_disconnect
                                     optional string, containing an integer, at least 1
       Connection Parameters:
         other_config : dscp         optional string, containing an integer
       Common Columns:
         external_ids                map of string-string pairs
         other_config                map of string-string pairs

   Details:
     Core Features:

       type: optional string, either primary or service
              Open vSwitch supports two kinds of OpenFlow controllers.  A  bridge  may  have  any
              number of each kind:

              Primary controllers
                     This  is  the  kind of controller envisioned by the OpenFlow specifications.
                     Usually, a primary controller implements a network policy by  taking  charge
                     of the switch’s flow table.

                     The fail_mode column in the Bridge table applies to primary controllers.

                     When  multiple  primary controllers are configured, Open vSwitch connects to
                     all of them  simultaneously.  OpenFlow  provides  few  facilities  to  allow
                     multiple  controllers  to coordinate in interacting with a single switch, so
                     more than one primary controller should be specified only if the controllers
                     are themselves designed to coordinate with each other.

              Service controllers
                     These  kinds  of OpenFlow controller connections are intended for occasional
                     support  and  maintenance  use,  e.g.  with  ovs-ofctl.  Usually  a  service
                     controller  connects  only  briefly  to inspect or modify some of a switch’s
                     state.

                     The fail_mode  column  in  the  Bridge  table  does  not  apply  to  service
                     controllers.

              By  default,  Open  vSwitch  treats  controllers  with active connection methods as
              primary  controllers  and  those  with  passive  connection  methods   as   service
              controllers. Set this column to the desired type to override this default.

       target: string
              Connection method for controller.

              The following active connection methods are currently supported:

              ssl:host[:port]
                     The  specified SSL port on the host at the given host, which can either be a
                     DNS name (if built with unbound library) or an IP address. The ssl column in
                     the  Open_vSwitch  table  must  point to a valid SSL configuration when this
                     form is used.

                     If port is not specified, it defaults to 6653.

                     SSL support is an optional feature that is not always built as part of  Open
                     vSwitch.

              tcp:host[:port]
                     The  specified TCP port on the host at the given host, which can either be a
                     DNS name (if built with unbound library) or an IP address (IPv4 or IPv6). If
                     host is an IPv6 address, wrap it in square brackets, e.g. tcp:[::1]:6653.

                     If port is not specified, it defaults to 6653.

              The following passive connection methods are currently supported:

              pssl:[port][:host]
                     Listens  for  SSL  connections on the specified TCP port. If host, which can
                     either be a DNS name (if built with unbound library) or an  IP  address,  is
                     specified,  then  connections  are  restricted  to the resolved or specified
                     local IP address (either IPv4 or IPv6). If host is an IPv6 address, wrap  it
                     in square brackets, e.g. pssl:6653:[::1].

                     If port is not specified, it defaults to 6653. If host is not specified then
                     it listens only on IPv4 (but not IPv6) addresses.  The  ssl  column  in  the
                     Open_vSwitch table must point to a valid SSL configuration when this form is
                     used.

                     If port is not specified, it currently to 6653.

                     SSL support is an optional feature that is not always built as part of  Open
                     vSwitch.

              ptcp:[port][:host]
                     Listens for connections on the specified TCP port. If host, which can either
                     be a DNS name  (if  built  with  unbound  library)  or  an  IP  address,  is
                     specified,  then  connections  are  restricted  to the resolved or specified
                     local IP address (either IPv4 or IPv6). If host is an IPv6 address, wrap  it
                     in  square  brackets, e.g. ptcp:6653:[::1]. If host is not specified then it
                     listens only on IPv4 addresses.

                     If port is not specified, it defaults to 6653.

              When multiple controllers are configured for a single  bridge,  the  target  values
              must be unique. Duplicate target values yield unspecified results.

       connection_mode: optional string, either in-band or out-of-band
              If  it  is  specified,  this  setting  must  be  one  of the following strings that
              describes how Open vSwitch contacts this OpenFlow controller over the network:

              in-band
                     In this mode, this controller’s OpenFlow traffic  travels  over  the  bridge
                     associated  with  the  controller.  With  this  setting, Open vSwitch allows
                     traffic to and from  the  controller  regardless  of  the  contents  of  the
                     OpenFlow flow table. (Otherwise, Open vSwitch would never be able to connect
                     to the controller, because it did not have a flow to enable it.) This is the
                     most  common  connection  mode  because  it is not necessary to maintain two
                     independent networks.

              out-of-band
                     In this mode, OpenFlow traffic uses a  control  network  separate  from  the
                     bridge associated with this controller, that is, the bridge does not use any
                     of its own network devices to communicate with the controller.  The  control
                     network  must  be  configured  separately,  before  or after ovs-vswitchd is
                     started.

              If not specified, the default is implementation-specific.

     Controller Failure Detection and Handling:

       max_backoff: optional integer, at least 1,000
              Maximum number of milliseconds to wait  between  connection  attempts.  Default  is
              implementation-specific.

       inactivity_probe: optional integer
              Maximum  number  of  milliseconds  of  idle time on connection to controller before
              sending an inactivity probe message. If Open vSwitch does not communicate with  the
              controller for the specified number of seconds, it will send a probe. If a response
              is not received for the same additional amount of time, Open  vSwitch  assumes  the
              connection  has  been  broken and attempts to reconnect. Default is implementation-
              specific. A value of 0 disables inactivity probes.

     Asynchronous Messages:

       OpenFlow switches send certain messages to controllers spontanenously,  that  is,  not  in
       response  to  any  request  from  the controller. These messages are called ``asynchronous
       messages.’’ These columns allow asynchronous messages to be limited or disabled to  ensure
       the best use of network resources.

       enable_async_messages: optional boolean
              The   OpenFlow  protocol  enables  asynchronous  messages  at  time  of  connection
              establishment, which means that a controller  can  receive  asynchronous  messages,
              potentially  many  of them, even if it turns them off immediately after connecting.
              Set this column to false to change Open vSwitch behavior to  disable,  by  default,
              all  asynchronous  messages. The controller can use the NXT_SET_ASYNC_CONFIG Nicira
              extension to OpenFlow to turn on any messages that it does want to receive, if any.

     Controller Rate Limiting:

       A switch can forward packets to  a  controller  over  the  OpenFlow  protocol.  Forwarding
       packets  this  way  at  too  high  a rate can overwhelm a controller, frustrate use of the
       OpenFlow connection for other purposes, increase the latency of flow  setup,  and  use  an
       unreasonable  amount  of  bandwidth. Therefore, Open vSwitch supports limiting the rate of
       packet forwarding to a controller.

       There are two main reasons in OpenFlow for a packet to be sent to a controller: either the
       packet  ``misses’’  in the flow table, that is, there is no matching flow, or a flow table
       action says to send the packet to the controller. Open vSwitch limits  the  rate  of  each
       kind  of packet separately at the configured rate. Therefore, the actual rate that packets
       are sent to the controller can be up to twice the configured rate, when packets  are  sent
       for both reasons.

       This  feature  is  specific  to  forwarding packets over an OpenFlow connection. It is not
       general-purpose QoS.  See  the  QoS  table  for  quality  of  service  configuration,  and
       ingress_policing_rate in the Interface table for ingress policing configuration.

       controller_queue_size: optional integer, in range 1 to 512
              This  sets  the  maximum  size of the queue of packets that need to be sent to this
              OpenFlow controller. The value must be less than 512. If not  specified  the  queue
              size   is   limited   to   the   value   set   for  the  management  controller  in
              other_config:controller-queue-size if present or  100  packets  by  default.  Note:
              increasing the queue size might have a negative impact on latency.

       controller_rate_limit: optional integer, at least 100
              The  maximum  rate  at  which  the  switch  will  forward  packets  to the OpenFlow
              controller, in packets per second. If no  value  is  specified,  rate  limiting  is
              disabled.

       controller_burst_limit: optional integer, at least 25
              When  a  high  rate  triggers  rate-limiting,  Open  vSwitch  queues packets to the
              controller for each port and transmits them to the  controller  at  the  configured
              rate.  This  value limits the number of queued packets. Ports on a bridge share the
              packet queue fairly.

              This value has no effect unless controller_rate_limit is  configured.  The  current
              default  when  this value is not specified is one-quarter of controller_rate_limit,
              meaning that queuing can delay forwarding a packet to the controller by up  to  250
              ms.

     Controller Rate Limiting Statistics:

       These  values  report  the  effects  of  rate  limiting.  Their  values  are  relative  to
       establishment of the most recent OpenFlow connection, or since rate limiting was  enabled,
       whichever  happened  more recently. Each consists of two values, one with TYPE replaced by
       miss for rate limiting flow table misses, and the other with TYPE replaced by  action  for
       rate limiting packets sent by OpenFlow actions.

       These statistics are reported only when controller rate limiting is enabled.

       status : packet-in-TYPE-bypassed: optional string, containing an integer, at least 0
              Number  of  packets  sent  directly to the controller, without queuing, because the
              rate did not exceed the configured maximum.

       status : packet-in-TYPE-queued: optional string, containing an integer, at least 0
              Number of packets added to the queue to send later.

       status : packet-in-TYPE-dropped: optional string, containing an integer, at least 0
              Number of packets added to the queue that were later dropped due to overflow.  This
              value is less than or equal to status:packet-in-TYPE-queued.

       status : packet-in-TYPE-backlog: optional string, containing an integer, at least 0
              Number  of  packets  currently queued. The other statistics increase monotonically,
              but this one fluctuates between 0  and  the  controller_burst_limit  as  conditions
              change.

     Additional In-Band Configuration:

       These values are considered only in in-band control mode (see connection_mode).

       When  multiple controllers are configured on a single bridge, there should be only one set
       of unique values in these columns. If different  values  are  set  for  these  columns  in
       different controllers, the effect is unspecified.

       local_ip: optional string
              The IP address to configure on the local port, e.g. 192.168.0.123. If this value is
              unset, then local_netmask and local_gateway are ignored.

       local_netmask: optional string
              The IP netmask to configure on the local port, e.g. 255.255.255.0. If  local_ip  is
              set  but  this  value  is unset, then the default is chosen based on whether the IP
              address is class A, B, or C.

       local_gateway: optional string
              The IP address of the gateway to configure on the local port,  as  a  string,  e.g.
              192.168.0.1. Leave this column unset if this network has no gateway.

     Controller Status:

       is_connected: boolean
              true if currently connected to this controller, false otherwise.

       role: optional string, one of master, other, or slave
              The  level  of  authority  this  controller  has on the associated bridge. Possible
              values are:

              other  Allows the controller access to all OpenFlow features.

              master Equivalent to other, except that there may be at most one such controller at
                     a  time.  If  a  given controller promotes itself to this role, ovs-vswitchd
                     demotes any existing controller with the role to slave.

              slave  Allows the controller read-only access to  OpenFlow  features.  Attempts  to
                     modify  the  flow  table will be rejected with an error. Such controllers do
                     not receive  OFPT_PACKET_IN  or  OFPT_FLOW_REMOVED  messages,  but  they  do
                     receive OFPT_PORT_STATUS messages.

       status : last_error: optional string
              A human-readable description of the last error on the connection to the controller;
              i.e. strerror(errno). This key will exist only if an error has occurred.

       status : state: optional string, one of ACTIVE, BACKOFF, CONNECTING, IDLE, or VOID
              The state of the connection to the controller:

              VOID   Connection is disabled.

              BACKOFF
                     Attempting to reconnect at an increasing period.

              CONNECTING
                     Attempting to connect.

              ACTIVE Connected, remote host responsive.

              IDLE   Connection is idle. Waiting for response to keep-alive.

              These  values  may  change  in  the  future.  They  are  provided  only  for  human
              consumption.

       status : sec_since_connect: optional string, containing an integer, at least 0
              The  amount of time since this controller last successfully connected to the switch
              (in seconds). Value is empty if controller has never successfully connected.

       status : sec_since_disconnect: optional string, containing an integer, at least 1
              The amount of time since this controller last  disconnected  from  the  switch  (in
              seconds). Value is empty if controller has never disconnected.

     Connection Parameters:

       Additional configuration for a connection between the controller and the Open vSwitch.

       other_config : dscp: optional string, containing an integer
              The  Differentiated Service Code Point (DSCP) is specified using 6 bits in the Type
              of Service (TOS) field in the IP header. DSCP provides a mechanism to classify  the
              network traffic and provide Quality of Service (QoS) on IP networks. The DSCP value
              specified here is used when establishing the connection between the controller  and
              the  Open vSwitch. If no value is specified, a default value of 48 is chosen. Valid
              DSCP values must be in the range 0 to 63.

     Common Columns:

       The overall purpose of these columns is described under Common Columns at the beginning of
       this document.

       external_ids: map of string-string pairs

       other_config: map of string-string pairs

Manager TABLE

       Configuration for a database connection to an Open vSwitch database (OVSDB) client.

       This  table  primarily  configures  the Open vSwitch database (ovsdb-server), not the Open
       vSwitch  switch  (ovs-vswitchd).  The  switch  does  read  the  table  to  determine  what
       connections should be treated as in-band.

       The  Open  vSwitch  database server can initiate and maintain active connections to remote
       clients. It can also listen for database connections.

   Summary:
       Core Features:
         target                      string (must be unique within table)
         connection_mode             optional string, either in-band or out-of-band
       Client Failure Detection and Handling:
         max_backoff                 optional integer, at least 1,000
         inactivity_probe            optional integer
       Status:
         is_connected                boolean
         status : last_error         optional string
         status : state              optional string, one of ACTIVE, BACKOFF,  CONNECTING,  IDLE,
                                     or VOID
         status : sec_since_connect  optional string, containing an integer, at least 0
         status : sec_since_disconnect
                                     optional string, containing an integer, at least 0
         status : locks_held         optional string
         status : locks_waiting      optional string
         status : locks_lost         optional string
         status : n_connections      optional string, containing an integer, at least 2
         status : bound_port         optional string, containing an integer
       Connection Parameters:
         other_config : dscp         optional string, containing an integer
       Common Columns:
         external_ids                map of string-string pairs
         other_config                map of string-string pairs

   Details:
     Core Features:

       target: string (must be unique within table)
              Connection method for managers.

              The following connection methods are currently supported:

              ssl:host[:port]
                     The  specified SSL port on the host at the given host, which can either be a
                     DNS name (if built with unbound library) or an IP address. The ssl column in
                     the  Open_vSwitch  table  must  point to a valid SSL configuration when this
                     form is used.

                     If port is not specified, it defaults to 6640.

                     SSL support is an optional feature that is not always built as part of  Open
                     vSwitch.

              tcp:host[:port]
                     The  specified TCP port on the host at the given host, which can either be a
                     DNS name (if built with unbound library) or an IP address (IPv4 or IPv6). If
                     host is an IPv6 address, wrap it in square brackets, e.g. tcp:[::1]:6640.

                     If port is not specified, it defaults to 6640.

              pssl:[port][:host]
                     Listens for SSL connections on the specified TCP port. Specify 0 for port to
                     have the kernel automatically choose an available port. If host,  which  can
                     either  be  a  DNS name (if built with unbound library) or an IP address, is
                     specified, then connections are restricted  to  the  resolved  or  specified
                     local  IP address (either IPv4 or IPv6 address). If host is an IPv6 address,
                     wrap in square brackets, e.g. pssl:6640:[::1]. If host is not specified then
                     it  listens  only  on  IPv4  (but not IPv6) addresses. The ssl column in the
                     Open_vSwitch table must point to a valid SSL configuration when this form is
                     used.

                     If port is not specified, it defaults to 6640.

                     SSL  support is an optional feature that is not always built as part of Open
                     vSwitch.

              ptcp:[port][:host]
                     Listens for connections on the specified TCP port. Specify  0  for  port  to
                     have  the  kernel automatically choose an available port. If host, which can
                     either be a DNS name (if built with unbound library) or an  IP  address,  is
                     specified,  then  connections  are  restricted  to the resolved or specified
                     local IP address (either IPv4 or IPv6 address). If host is an IPv6  address,
                     wrap  it  in square brackets, e.g. ptcp:6640:[::1]. If host is not specified
                     then it listens only on IPv4 addresses.

                     If port is not specified, it defaults to 6640.

              When multiple managers are configured, the target values must be unique.  Duplicate
              target values yield unspecified results.

       connection_mode: optional string, either in-band or out-of-band
              If  it  is  specified,  this  setting  must  be  one  of the following strings that
              describes how Open vSwitch contacts this OVSDB client over the network:

              in-band
                     In this mode, this connection’s traffic travels over  a  bridge  managed  by
                     Open vSwitch. With this setting, Open vSwitch allows traffic to and from the
                     client regardless of the contents of the OpenFlow  flow  table.  (Otherwise,
                     Open  vSwitch  would  never be able to connect to the client, because it did
                     not have a flow to enable it.) This  is  the  most  common  connection  mode
                     because it is not necessary to maintain two independent networks.

              out-of-band
                     In this mode, the client’s traffic uses a control network separate from that
                     managed by Open vSwitch, that is, Open vSwitch does not use any of  its  own
                     network  devices to communicate with the client. The control network must be
                     configured separately, before or after ovs-vswitchd is started.

              If not specified, the default is implementation-specific.

     Client Failure Detection and Handling:

       max_backoff: optional integer, at least 1,000
              Maximum number of milliseconds to wait  between  connection  attempts.  Default  is
              implementation-specific.

       inactivity_probe: optional integer
              Maximum  number  of  milliseconds  of  idle time on connection to the client before
              sending an inactivity probe message. If Open vSwitch does not communicate with  the
              client  for the specified number of seconds, it will send a probe. If a response is
              not received for the same additional amount  of  time,  Open  vSwitch  assumes  the
              connection  has  been  broken and attempts to reconnect. Default is implementation-
              specific. A value of 0 disables inactivity probes.

     Status:

       Key-value pair of is_connected is always updated. Other  key-value  pairs  in  the  status
       columns may be updated depends on the target type.

       When target specifies a connection method that listens for inbound connections (e.g. ptcp:
       or punix:), both n_connections and is_connected may also be updated  while  the  remaining
       key-value pairs are omitted.

       On  the  other hand, when target specifies an outbound connection, all key-value pairs may
       be updated, except  the  above-mentioned  two  key-value  pairs  associated  with  inbound
       connection targets. They are omitted.

       is_connected: boolean
              true if currently connected to this manager, false otherwise.

       status : last_error: optional string
              A  human-readable  description  of the last error on the connection to the manager;
              i.e. strerror(errno). This key will exist only if an error has occurred.

       status : state: optional string, one of ACTIVE, BACKOFF, CONNECTING, IDLE, or VOID
              The state of the connection to the manager:

              VOID   Connection is disabled.

              BACKOFF
                     Attempting to reconnect at an increasing period.

              CONNECTING
                     Attempting to connect.

              ACTIVE Connected, remote host responsive.

              IDLE   Connection is idle. Waiting for response to keep-alive.

              These  values  may  change  in  the  future.  They  are  provided  only  for  human
              consumption.

       status : sec_since_connect: optional string, containing an integer, at least 0
              The  amount  of time since this manager last successfully connected to the database
              (in seconds). Value is empty if manager has never successfully connected.

       status : sec_since_disconnect: optional string, containing an integer, at least 0
              The amount of time since this manager  last  disconnected  from  the  database  (in
              seconds). Value is empty if manager has never disconnected.

       status : locks_held: optional string
              Space-separated list of the names of OVSDB locks that the connection holds. Omitted
              if the connection does not hold any locks.

       status : locks_waiting: optional string
              Space-separated list of the names of OVSDB locks that the connection  is  currently
              waiting to acquire. Omitted if the connection is not waiting for any locks.

       status : locks_lost: optional string
              Space-separated list of the names of OVSDB locks that the connection has had stolen
              by another OVSDB client. Omitted if no locks have been stolen from this connection.

       status : n_connections: optional string, containing an integer, at least 2
              When target specifies a connection method  that  listens  for  inbound  connections
              (e.g. ptcp: or pssl:) and more than one connection is actually active, the value is
              the number of active connections. Otherwise, this key-value pair is omitted.

       status : bound_port: optional string, containing an integer
              When target is ptcp: or pssl:, this is the TCP port on which the  OVSDB  server  is
              listening. (This is particularly useful when target specifies a port of 0, allowing
              the kernel to choose any available port.)

     Connection Parameters:

       Additional configuration for a  connection  between  the  manager  and  the  Open  vSwitch
       Database.

       other_config : dscp: optional string, containing an integer
              The  Differentiated Service Code Point (DSCP) is specified using 6 bits in the Type
              of Service (TOS) field in the IP header. DSCP provides a mechanism to classify  the
              network traffic and provide Quality of Service (QoS) on IP networks. The DSCP value
              specified here is used when establishing the connection between the manager and the
              Open vSwitch. If no value is specified, a default value of 48 is chosen. Valid DSCP
              values must be in the range 0 to 63.

     Common Columns:

       The overall purpose of these columns is described under Common Columns at the beginning of
       this document.

       external_ids: map of string-string pairs

       other_config: map of string-string pairs

NetFlow TABLE

       A NetFlow target. NetFlow is a protocol that exports a number of details about terminating
       IP flows, such as the principals involved and duration.

   Summary:
       targets                       set of 1 or more strings
       engine_id                     optional integer, in range 0 to 255
       engine_type                   optional integer, in range 0 to 255
       active_timeout                integer, at least -1
       add_id_to_interface           boolean
       Common Columns:
         external_ids                map of string-string pairs

   Details:
       targets: set of 1 or more strings
              NetFlow targets in the form ip:port. The ip must be specified numerically, not as a
              DNS name.

       engine_id: optional integer, in range 0 to 255
              Engine ID to use in NetFlow messages. Defaults to datapath index if not specified.

       engine_type: optional integer, in range 0 to 255
              Engine  type  to  use  in  NetFlow  messages.  Defaults  to  datapath  index if not
              specified.

       active_timeout: integer, at least -1
              The interval at which NetFlow records are sent for flows that are still active,  in
              seconds. A value of 0 requests the default timeout (currently 600 seconds); a value
              of -1 disables active timeouts.

              The NetFlow passive timeout, for flows that become inactive, is  not  configurable.
              It  will  vary depending on the Open vSwitch version, the forms and contents of the
              OpenFlow flow tables, CPU and memory usage, and network activity. A typical passive
              timeout is about a second.

       add_id_to_interface: boolean
              If this column’s value is false, the ingress and egress interface fields of NetFlow
              flow records are derived from OpenFlow port numbers. When it is true,  the  7  most
              significant  bits  of these fields will be replaced by the least significant 7 bits
              of the engine id. This is useful because many  NetFlow  collectors  do  not  expect
              multiple  switches  to be sending messages from the same host, so they do not store
              the engine information which could be used to disambiguate the traffic.

              When this option is enabled, a maximum of 508 ports are supported.

     Common Columns:

       The overall purpose of these columns is described under Common Columns at the beginning of
       this document.

       external_ids: map of string-string pairs

Datapath TABLE

       Configuration for a datapath within Open_vSwitch.

       A datapath is responsible for providing the packet handling in Open vSwitch. There are two
       primary datapath implementations used  by  Open  vSwitch:  kernel  and  userspace.  Kernel
       datapath  implementations  are  available for Linux and Hyper-V, and selected as system in
       the datapath_type column of the Bridge table. The userspace datapath is used by  DPDK  and
       AF-XDP, and is selected as netdev in the datapath_type column of the Bridge table.

       A datapath of a particular type is shared by all the bridges that use that datapath. Thus,
       configurations applied to this table affect all bridges that use this datapath.

   Summary:
       datapath_version              string
       ct_zones                      map of integer-CT_Zone pairs, key in range 0 to 65,535
       Capabilities:
         capabilities : max_vlan_headers
                                     optional string, containing an integer, at least 0
         capabilities : recirc       optional string, either true or false
         capabilities : lb_output_action
                                     optional string, either true or false
         Connection-Tracking Capabilities:
            capabilities : ct_state  optional string, either true or false
            capabilities : ct_state_nat
                                     optional string, either true or false
            capabilities : ct_zone   optional string, either true or false
            capabilities : ct_mark   optional string, either true or false
            capabilities : ct_label  optional string, either true or false
            capabilities : ct_orig_tuple
                                     optional string, either true or false
            capabilities : ct_orig_tuple6
                                     optional string, either true or false
         capabilities : masked_set_action
                                     optional string, either true or false
         capabilities : tnl_push_pop
                                     optional string, either true or false
         capabilities : ufid         optional string, either true or false
         capabilities : trunc        optional string, either true or false
         capabilities : nd_ext       optional string, either true or false
         Clone Actions:
            capabilities : clone     optional string, either true or false
            capabilities : sample_nesting
                                     optional string, containing an integer, at least 0
         capabilities : ct_eventmask
                                     optional string, either true or false
         capabilities : ct_clear     optional string, either true or false
         capabilities : max_hash_alg
                                     optional string, containing an integer, at least 0
         capabilities : check_pkt_len
                                     optional string, either true or false
         capabilities : ct_timeout   optional string, either true or false
         capabilities : explicit_drop_action
                                     optional string, either true or false
         capabilities : ct_zero_snat
                                     optional string, either true or false
         capabilities : ct_flush     optional string, either true or false
       Common Columns:
         external_ids                map of string-string pairs

   Details:
       datapath_version: string
              Reports the version number of  the  Open  vSwitch  datapath  in  use.  This  allows
              management  software  to  detect  and  report  discrepancies  between  Open vSwitch
              userspace and datapath  versions.  (The  ovs_version  column  in  the  Open_vSwitch
              reports  the  Open  vSwitch userspace version.) The version reported depends on the
              datapath in use:

              •      When the kernel module included in the Open vSwitch  source  tree  is  used,
                     this  column  reports  the  Open  vSwitch  version from which the module was
                     taken.

              •      When the kernel module that is part of the upstream Linux  kernel  is  used,
                     this column reports <unknown>.

              •      When the datapath is built into the ovs-vswitchd binary, this column reports
                     <built-in>. A built-in datapath is by definition the  same  version  as  the
                     rest of the Open vSwitch userspace.

              •      Other  datapaths  (such  as  the  Hyper-V  kernel datapath) currently report
                     <unknown>.

              A version discrepancy between ovs-vswitchd and the datapath in use is not  normally
              cause  for  alarm.  The  Open  vSwitch  kernel  datapaths for Linux and Hyper-V, in
              particular, are designed for maximum  inter-version  compatibility:  any  userspace
              version  works  with  with  any  kernel version. Some reasons do exist to insist on
              particular user/kernel pairings. First, newer kernel  versions  add  new  features,
              that  can  only  be  used  by  new-enough  userspace, e.g. VXLAN tunneling requires
              certain minimal userspace and kernel versions. Second, as an extension to the first
              reason,  some newer kernel versions add new features for enhancing performance that
              only new-enough userspace versions can take advantage of.

       ct_zones: map of integer-CT_Zone pairs, key in range 0 to 65,535
              Configuration for connection tracking zones. Each pair maps from a  zone  id  to  a
              configuration  for  that zone. Zone 0 applies to the default zone (ie, the one used
              if a zone is not specified in  connection  tracking-related  OpenFlow  matches  and
              actions).

     Capabilities:

       The  capabilities  column  reports  a  datapath’s  features.  For the netdev datapath, the
       capabilities are fixed for a given version of Open vSwitch because this datapath is  built
       into  the ovs-vswitchd binary. The Linux kernel and Windows and other datapaths, which are
       external to OVS userspace,  can  vary  in  version  and  capabilities  independently  from
       ovs-vswitchd.

       Some  of these features indicate whether higher-level Open vSwitch features are available.
       For  example,  OpenFlow  features  for  connection-tracking  are   available   only   when
       capabilities:ct_state  is true. A controller that wishes to determine whether a feature is
       supported could, therefore, consult the relevant capabilities in this table. However, as a
       general rule, it is better for a controller to try to use the higher-level feature and use
       the result as an indication of support, since the low-level capabilities are  more  likely
       to shift over time than the high-level features that rely on them.

       capabilities : max_vlan_headers: optional string, containing an integer, at least 0
              Number  of  802.1q  VLAN  headers  supported  by  the  datapath,  as  probed by the
              ovs-vswitchd slow path. If the datapath supports more VLAN headers  than  the  slow
              path,  this  reports the slow path’s limit. The value of other-config:vlan-limit in
              the Open_vSwitch table does not influence the number reported here.

       capabilities : recirc: optional string, either true or false
              If  this  is  true,  then  the  datapath   supports   recirculation,   specifically
              OVS_KEY_ATTR_RECIRC_ID.  Recirculation  enables  higher  performance  for  MPLS and
              active-active load balancing bonding modes.

       capabilities : lb_output_action: optional string, either true or false
              If this is true, then the datapath supports optimized balance-tcp bond  mode.  This
              capability  replaces existing hash and recirc actions with new action lb_output and
              avoids recirculation of packet in datapath. It is supported  only  for  balance-tcp
              bond mode in netdev datapath. The new action gives higher performance by using bond
              buckets instead of post recirculation flows for selection of slave port from  bond.
              By default this new action is disabled, however it can be enabled by setting other-
              config:lb-output-action in Port table.

     Connection-Tracking Capabilities:

       These capabilities are granular because Open vSwitch and its datapaths added  support  for
       connection  tracking  over  several  releases,  with features added individually over that
       time.

       capabilities : ct_state: optional string, either true or false
              If true, datapath supports OVS_KEY_ATTR_CT_STATE, which indicates support  for  the
              bits  in  the OpenFlow ct_state field (see ovs-fields(7)) other than snat and dnat,
              which have a separate capability.

              If this is false, the datapath does not support connection-tracking at all and  the
              remaining  connection-tracking capabilities should all be false. In this case, Open
              vSwitch will reject flows that match on the ct_state field or use the ct action.

       capabilities : ct_state_nat: optional string, either true or false
              If true, it means that the datapath  supports  the  snat  and  dnat  flags  in  the
              OpenFlow  ct_state  field.  The  ct_state  capability must be true for this to make
              sense.

              If false, Open vSwitch will reject flows that match on the snat  or  dnat  bits  in
              ct_state or use nat in the ct action.

       capabilities : ct_zone: optional string, either true or false
              If  true,  datapath  supports  OVS_KEY_ATTR_CT_ZONE. If false, Open vSwitch rejects
              flows that match on the ct_zone field or that specify a  nonzero  zone  or  a  zone
              field on the ct action.

       capabilities : ct_mark: optional string, either true or false
              If  true,  datapath  supports  OVS_KEY_ATTR_CT_MARK. If false, Open vSwitch rejects
              flows that match on the ct_mark field or that set ct_mark in the ct action.

       capabilities : ct_label: optional string, either true or false
              If true, datapath supports OVS_KEY_ATTR_CT_LABEL. If false,  Open  vSwitch  rejects
              flows that match on the ct_label field or that set ct_label in the ct action.

       capabilities : ct_orig_tuple: optional string, either true or false
              If  true, the datapath supports matching the 5-tuple from the connection’s original
              direction for IPv4 traffic. If false, Open vSwitch  rejects  flows  that  match  on
              ct_nw_src  or  ct_nw_dst,  that  use  the ct feature of the resubmit action, or the
              force keyword in the ct action. (The  latter  isn’t  tied  to  connection  tracking
              support  of  original  tuples  in any technical way. They are conflated because all
              current datapaths implemented the two features at the same time.)

              If this and capabilities:ct_orig_tuple6 are both false, Open vSwitch rejects  flows
              that match on ct_nw_proto, ct_tp_src, or ct_tp_dst.

       capabilities : ct_orig_tuple6: optional string, either true or false
              If  true, the datapath supports matching the 5-tuple from the connection’s original
              direction for IPv6 traffic. If false, Open vSwitch  rejects  flows  that  match  on
              ct_ipv6_src or ct_ipv6_dst.

       capabilities : masked_set_action: optional string, either true or false
              True  if  the  datapath supports masked data in OVS_ACTION_ATTR_SET actions. Masked
              data can improve performance by allowing megaflows to match on fewer fields.

       capabilities : tnl_push_pop: optional string, either true or false
              True if the datapath supports tnl_push and pop actions. This is a prerequisite  for
              a datapath to support native tunneling.

       capabilities : ufid: optional string, either true or false
              True   if   the   datapath   supports  OVS_FLOW_ATTR_UFID.  UFID  support  improves
              revalidation performance by transferring less data between the slow  path  and  the
              datapath.

       capabilities : trunc: optional string, either true or false
              True  if  the  datapath supports OVS_ACTION_ATTR_TRUNC action. If false, the output
              action with packet truncation requires every packet to be sent to the Open  vSwitch
              slow path, which is likely to make it too slow for mirroring traffic in bulk.

       capabilities : nd_ext: optional string, either true or false
              True  if  the  datapath  supports OVS_KEY_ATTR_ND_EXTENSIONS to match on ICMPv6 "ND
              reserved" and "ND option type" header fields. If false, the datapath reports  error
              if the feature is used.

     Clone Actions:

       When  Open vSwitch translates actions from OpenFlow into the datapath representation, some
       of the datapath actions may modify the packet  or  have  other  side  effects  that  later
       datapath actions can’t undo. The OpenFlow ct, meter, output with truncation, encap, decap,
       and dec_nsh_ttl actions fall into this category. Often, this  is  not  a  problem  because
       nothing later on needs the original packet.

       Such  actions  can, however, occur in circumstances where the translation does require the
       original packet. For example, an OpenFlow output action might direct a packet to  a  patch
       port,  which  might  in  turn  lead  to  a ct action that NATs the packet (which cannot be
       undone), and then afterward when control flow pops back across the patch port  some  other
       action might need to act on the original packet.

       Open  vSwitch  has  two different ways to implement this ``save and restore’’ via datapath
       actions. These capabilities indicate which one Open vSwitch will choose. When  neither  is
       available, Open vSwitch simply fails in situations that require this feature.

       capabilities : clone: optional string, either true or false
              True  if  the datapath supports OVS_ACTION_ATTR_CLONE action. This is the preferred
              option for saving and restoring packets, since it is intended for the purpose,  but
              old datapaths do not support it. Open vSwitch will use it whenever it is available.

              (The OpenFlow clone action does not always yield a OVS_ACTION_ATTR_CLONE action. It
              only does so when the datapath supports it and  the  clone  brackets  actions  that
              otherwise cannot be undone.)

       capabilities : sample_nesting: optional string, containing an integer, at least 0
              Maximum  level  of  nesting  allowed by OVS_ACTION_ATTR_SAMPLE action. Open vSwitch
              misuses this action for saving and restoring packets  when  the  datapath  supports
              more than 3 levels of nesting and OVS_ACTION_ATTR_CLONE is not available.

       capabilities : ct_eventmask: optional string, either true or false
              True    if    the    datapath’s    OVS_ACTION_ATTR_CT    action    implements   the
              OVS_CT_ATTR_EVENTMASK attribute. When this is true, Open  vSwitch  uses  the  event
              mask  feature  to limit the kinds of events reported to conntrack update listeners.
              When Open vSwitch doesn’t limit  the  event  mask,  listeners  receive  reports  of
              numerous  usually  unimportant events, such as TCP state machine changes, which can
              waste CPU time.

       capabilities : ct_clear: optional string, either true or false
              True if the  datapath  supports  OVS_ACTION_ATTR_CT_CLEAR  action.  If  false,  the
              OpenFlow ct_clear action has no effect on the datapath.

       capabilities : max_hash_alg: optional string, containing an integer, at least 0
              Highest supported dp_hash algorithm. This allows Open vSwitch to avoid requesting a
              packet hash that the datapath does not support.

       capabilities : check_pkt_len: optional string, either true or false
              True if the datapath supports OVS_ACTION_ATTR_CHECK_PKT_LEN. If false, Open vSwitch
              implements  the  check_pkt_larger  action  by sending every packet through the Open
              vSwitch slow path, which is likely to make it too  slow  for  handling  traffic  in
              bulk.

       capabilities : ct_timeout: optional string, either true or false
              True if the datapath supports OVS_CT_ATTR_TIMEOUT in the OVS_ACTION_ATTR_CT action.
              If false, Open vswitch  cannot  implement  timeout  policies  based  on  connection
              tracking zones, as configured through the CT_Timeout_Policy table.

       capabilities : explicit_drop_action: optional string, either true or false
              True  if the datapath supports OVS_ACTION_ATTR_DROP. If false, explicit drop action
              will not be sent to the datapath.

       capabilities : ct_zero_snat: optional string, either true or false
              True if the datapath supports all-zero SNAT. This is a special case if the  src  IP
              address  is  configured  as  all  0’s, i.e., nat(src=0.0.0.0). In this case, when a
              source port collision is detected during  the  commit,  the  source  port  will  be
              translated to an ephemeral port. If there is no collision, no SNAT is performed.

       capabilities : ct_flush: optional string, either true or false
              True   if   the  datapath  supports  CT  flush  OpenFlow  Nicira  extension  called
              NXT_CT_FLUSH. The NXT_CT_FLUSH extensions allows  to  flush  CT  entries  based  on
              specified parameters.

     Common Columns:

       The overall purpose of these columns is described under Common Columns at the beginning of
       this document.

       external_ids: map of string-string pairs

CT_Zone TABLE

       Connection tracking zone configuration

   Summary:
       timeout_policy                optional CT_Timeout_Policy
       Common Columns:
         external_ids                map of string-string pairs

   Details:
       timeout_policy: optional CT_Timeout_Policy
              Connection tracking timeout policy for this  zone.  If  a  timeout  policy  is  not
              specified, it defaults to the timeout policy in the system.

     Common Columns:

       The overall purpose of these columns is described under Common Columns at the beginning of
       this document.

       external_ids: map of string-string pairs

CT_Timeout_Policy TABLE

       Connection tracking timeout policy configuration

   Summary:
       Timeouts:
         timeouts                    map  of  string-integer  pairs,  key  one   of   icmp_first,
                                     icmp_reply,   tcp_close,   tcp_close_wait,  tcp_established,
                                     tcp_fin_wait,  tcp_last_ack,  tcp_retransmit,  tcp_syn_recv,
                                     tcp_syn_sent2,   tcp_syn_sent,   tcp_time_wait,   tcp_unack,
                                     udp_first, udp_multiple, or udp_single, value in range 0  to
                                     4,294,967,295
         TCP Timeouts:
            timeouts : tcp_syn_sent  optional integer, in range 0 to 4,294,967,295
            timeouts : tcp_syn_recv  optional integer, in range 0 to 4,294,967,295
            timeouts : tcp_established
                                     optional integer, in range 0 to 4,294,967,295
            timeouts : tcp_fin_wait  optional integer, in range 0 to 4,294,967,295
            timeouts : tcp_close_wait
                                     optional integer, in range 0 to 4,294,967,295
            timeouts : tcp_last_ack  optional integer, in range 0 to 4,294,967,295
            timeouts : tcp_time_wait optional integer, in range 0 to 4,294,967,295
            timeouts : tcp_close     optional integer, in range 0 to 4,294,967,295
            timeouts : tcp_syn_sent2 optional integer, in range 0 to 4,294,967,295
            timeouts : tcp_retransmit
                                     optional integer, in range 0 to 4,294,967,295
            timeouts : tcp_unack     optional integer, in range 0 to 4,294,967,295
         UDP Timeouts:
            timeouts : udp_first     optional integer, in range 0 to 4,294,967,295
            timeouts : udp_single    optional integer, in range 0 to 4,294,967,295
            timeouts : udp_multiple  optional integer, in range 0 to 4,294,967,295
         ICMP Timeouts:
            timeouts : icmp_first    optional integer, in range 0 to 4,294,967,295
            timeouts : icmp_reply    optional integer, in range 0 to 4,294,967,295
       Common Columns:
         external_ids                map of string-string pairs

   Details:
     Timeouts:

       timeouts:  map  of  string-integer  pairs,  key  one of icmp_first, icmp_reply, tcp_close,
       tcp_close_wait, tcp_established, tcp_fin_wait, tcp_last_ack, tcp_retransmit, tcp_syn_recv,
       tcp_syn_sent2,   tcp_syn_sent,   tcp_time_wait,  tcp_unack,  udp_first,  udp_multiple,  or
       udp_single, value in range 0 to 4,294,967,295
              The timeouts column contains key-value pairs used to configure connection  tracking
              timeouts  in  a  datapath. Key-value pairs that are not supported by a datapath are
              ignored. The timeout value is in seconds.

     TCP Timeouts:

       timeouts : tcp_syn_sent: optional integer, in range 0 to 4,294,967,295
              The timeout for the connection after the first TCP SYN  packet  has  been  seen  by
              conntrack.

       timeouts : tcp_syn_recv: optional integer, in range 0 to 4,294,967,295
              The  timeout  of the connection after the first TCP SYN-ACK packet has been seen by
              conntrack.

       timeouts : tcp_established: optional integer, in range 0 to 4,294,967,295
              The timeout of the connection after the connection has been fully established.

       timeouts : tcp_fin_wait: optional integer, in range 0 to 4,294,967,295
              The timeout of the connection after the first TCP  FIN  packet  has  been  seen  by
              conntrack.

       timeouts : tcp_close_wait: optional integer, in range 0 to 4,294,967,295
              The timeout of the connection after the first TCP ACK packet has been seen after it
              receives TCP FIN packet. This  timeout  is  only  supported  by  the  Linux  kernel
              datapath.

       timeouts : tcp_last_ack: optional integer, in range 0 to 4,294,967,295
              The  timeout  of  the  connection after TCP FIN packets have been seen by conntrack
              from both directions. This timeout is only supported by the Linux kernel datapath.

       timeouts : tcp_time_wait: optional integer, in range 0 to 4,294,967,295
              The timeout of the connection after conntrack has seen the TCP ACK packet  for  the
              second TCP FIN packet.

       timeouts : tcp_close: optional integer, in range 0 to 4,294,967,295
              The  timeout  of  the  connection  after  the first TCP RST packet has been seen by
              conntrack.

       timeouts : tcp_syn_sent2: optional integer, in range 0 to 4,294,967,295
              The timeout of the connection when only a TCP SYN packet has been seen by conntrack
              from  both  directions  (simultaneous  open). This timeout is only supported by the
              Linux kernel datapath.

       timeouts : tcp_retransmit: optional integer, in range 0 to 4,294,967,295
              The  timeout  of  the  connection  when  it   exceeds   the   maximum   number   of
              retransmissions. This timeout is only supported by the Linux kernel datapath.

       timeouts : tcp_unack: optional integer, in range 0 to 4,294,967,295
              The timeout of the connection when non-SYN packets create an established connection
              in TCP loose tracking mode. This timeout is only  supported  by  the  Linux  kernel
              datapath.

     UDP Timeouts:

       timeouts : udp_first: optional integer, in range 0 to 4,294,967,295
              The  timeout  of  the  connection  after  the  first  UDP  packet  has been seen by
              conntrack. This timeout is only supported by the userspace datapath.

       timeouts : udp_single: optional integer, in range 0 to 4,294,967,295
              The timeout of the connection when conntrack only seen UDP packet from  the  source
              host, but the destination host has never sent one back.

       timeouts : udp_multiple: optional integer, in range 0 to 4,294,967,295
              The timeout of the connection when UDP packets have been seen in both directions.

     ICMP Timeouts:

       timeouts : icmp_first: optional integer, in range 0 to 4,294,967,295
              The  timeout  of  the  connection  after  the  first  ICMP  packet has been seen by
              conntrack.

       timeouts : icmp_reply: optional integer, in range 0 to 4,294,967,295
              The timeout of the connection when ICMP packets have been seen in  both  direction.
              This timeout is only supported by the userspace datapath.

     Common Columns:

       The overall purpose of these columns is described under Common Columns at the beginning of
       this document.

       external_ids: map of string-string pairs

SSL TABLE

       SSL configuration for an Open_vSwitch.

   Summary:
       private_key                   string
       certificate                   string
       ca_cert                       string
       bootstrap_ca_cert             boolean
       Common Columns:
         external_ids                map of string-string pairs

   Details:
       private_key: string
              Name of a PEM file containing the private key used as the switch’s identity for SSL
              connections to the controller.

       certificate: string
              Name  of  a  PEM file containing a certificate, signed by the certificate authority
              (CA) used by the controller and manager, that certifies the switch’s  private  key,
              identifying a trustworthy switch.

       ca_cert: string
              Name  of a PEM file containing the CA certificate used to verify that the switch is
              connected to a trustworthy controller.

       bootstrap_ca_cert: boolean
              If set to true, then Open vSwitch will attempt to obtain the  CA  certificate  from
              the controller on its first SSL connection and save it to the named PEM file. If it
              is successful, it will immediately drop the connection and reconnect, and from then
              on  all  SSL  connections  must  be authenticated by a certificate signed by the CA
              certificate  thus  obtained.  This  option  exposes  the  SSL   connection   to   a
              man-in-the-middle  attack  obtaining  the  initial  CA certificate. It may still be
              useful for bootstrapping.

     Common Columns:

       The overall purpose of these columns is described under Common Columns at the beginning of
       this document.

       external_ids: map of string-string pairs

sFlow TABLE

       A set of sFlow(R) targets. sFlow is a protocol for remote monitoring of switches.

   Summary:
       agent                         optional string
       header                        optional integer
       polling                       optional integer
       sampling                      optional integer
       targets                       set of 1 or more strings
       Common Columns:
         external_ids                map of string-string pairs

   Details:
       agent: optional string
              Determines the agent address, that is, the IP address reported to collectors as the
              source of the sFlow data. It may be an IP address or the name of a network  device.
              In the latter case, the network device’s IP address is used,

              If not specified, the agent device is figured from the first target address and the
              routing table. If the routing table does not contain a route to the target, the  IP
              address defaults to the local_ip in the collector’s Controller.

              If an agent IP address cannot be determined, sFlow is disabled.

       header: optional integer
              Number of bytes of a sampled packet to send to the collector. If not specified, the
              default is 128 bytes.

       polling: optional integer
              Polling rate in seconds to send port statistics to the collector. If not specified,
              defaults to 30 seconds.

       sampling: optional integer
              Rate  at  which  packets  should  be  sampled  and  sent  to  the collector. If not
              specified, defaults to 400, which means one out of 400 packets, on average, will be
              sent to the collector.

       targets: set of 1 or more strings
              sFlow targets in the form ip:port.

     Common Columns:

       The overall purpose of these columns is described under Common Columns at the beginning of
       this document.

       external_ids: map of string-string pairs

IPFIX TABLE

       Configuration for sending packets to IPFIX collectors.

       IPFIX is a protocol that exports a number of details about flows. The IPFIX implementation
       in  Open  vSwitch  samples  packets at a configurable rate, extracts flow information from
       those packets, optionally caches and aggregates the flow information, and sends the result
       to one or more collectors.

       IPFIX in Open vSwitch can be configured two different ways:

              •      With per-bridge sampling, Open vSwitch performs IPFIX sampling automatically
                     on all packets that pass through a bridge. To configure per-bridge sampling,
                     create  an  IPFIX  record and point a Bridge table’s ipfix column to it. The
                     Flow_Sample_Collector_Set table is not used for per-bridge sampling.

              •      With flow-based sampling, sample actions in the OpenFlow  flow  table  drive
                     IPFIX sampling. See ovs-actions(7) for a description of the sample action.

                     Flow-based  sampling  also  requires  database configuration: create a IPFIX
                     record    that    describes    the     IPFIX     configuration     and     a
                     Flow_Sample_Collector_Set  record that points to the Bridge whose flow table
                     holds the sample actions and to IPFIX record. The ipfix in the Bridge  table
                     is not used for flow-based sampling.

   Summary:
       targets                       set of strings
       cache_active_timeout          optional integer, in range 0 to 4,200
       cache_max_flows               optional integer, in range 0 to 4,294,967,295
       stats_interval                optional integer, in range 1 to 3,600
       template_interval             optional integer, in range 1 to 3,600
       other_config : enable-tunnel-sampling
                                     optional string, either true or false
       other_config : virtual_obs_id optional string
       Per-Bridge Sampling:
         sampling                    optional integer, in range 1 to 4,294,967,295
         obs_domain_id               optional integer, in range 0 to 4,294,967,295
         obs_point_id                optional integer, in range 0 to 4,294,967,295
         other_config : enable-input-sampling
                                     optional string, either true or false
         other_config : enable-output-sampling
                                     optional string, either true or false
       Common Columns:
         external_ids                map of string-string pairs

   Details:
       targets: set of strings
              IPFIX target collectors in the form ip:port.

       cache_active_timeout: optional integer, in range 0 to 4,200
              The  maximum  period  in  seconds  for  which  an  IPFIX  flow record is cached and
              aggregated before being sent. If not specified, defaults to 0.  If  0,  caching  is
              disabled.

       cache_max_flows: optional integer, in range 0 to 4,294,967,295
              The  maximum  number  of  IPFIX  flow  records that can be cached at a time. If not
              specified, defaults to 0. If 0, caching is disabled.

       stats_interval: optional integer, in range 1 to 3,600
              Interval (in seconds) for sending IPFIX exporting process statistics  according  to
              IETF RFC 5101 Section 4.3.

              Default value is 600

       template_interval: optional integer, in range 1 to 3,600
              Interval  (in  seconds) for sending IPFIX Template information for each Observation
              Domain ID.

              Default value is 600

       other_config : enable-tunnel-sampling: optional string, either true or false
              Set to true to enable sampling and reporting tunnel header 7-tuples in  IPFIX  flow
              records. Tunnel sampling is enabled by default.

              The following enterprise entities report the sampled tunnel info:

              tunnelType:
                     ID: 891, and enterprise ID 6876 (VMware).

                     type: unsigned 8-bit integer.

                     data type semantics: identifier.

                     description: Identifier of the layer 2 network overlay network encapsulation
                     type: 0x01 VxLAN, 0x02 GRE, 0x03 LISP, 0x07 GENEVE.

              tunnelKey:
                     ID: 892, and enterprise ID 6876 (VMware).

                     type: variable-length octetarray.

                     data type semantics: identifier.

                     description: Key which is used for identifying an  individual  traffic  flow
                     within  a VxLAN (24-bit VNI), GENEVE (24-bit VNI), GRE (32-bit key), or LISP
                     (24-bit instance ID) tunnel. The key is encoded in this octetarray as a  3-,
                     4-, or 8-byte integer ID in network byte order.

              tunnelSourceIPv4Address:
                     ID: 893, and enterprise ID 6876 (VMware).

                     type: unsigned 32-bit integer.

                     data type semantics: identifier.

                     description: The IPv4 source address in the tunnel IP packet header.

              tunnelDestinationIPv4Address:
                     ID: 894, and enterprise ID 6876 (VMware).

                     type: unsigned 32-bit integer.

                     data type semantics: identifier.

                     description: The IPv4 destination address in the tunnel IP packet header.

              tunnelProtocolIdentifier:
                     ID: 895, and enterprise ID 6876 (VMware).

                     type: unsigned 8-bit integer.

                     data type semantics: identifier.

                     description:  The  value  of  the  protocol  number  in the tunnel IP packet
                     header. The protocol number identifies the tunnel IP packet payload type.

              tunnelSourceTransportPort:
                     ID: 896, and enterprise ID 6876 (VMware).

                     type: unsigned 16-bit integer.

                     data type semantics: identifier.

                     description: The source port identifier in the tunnel transport header.  For
                     the  transport  protocols UDP, TCP, and SCTP, this is the source port number
                     given in the respective header.

              tunnelDestinationTransportPort:
                     ID: 897, and enterprise ID 6876 (VMware).

                     type: unsigned 16-bit integer.

                     data type semantics: identifier.

                     description: The destination port identifier in the tunnel transport header.
                     For the transport protocols UDP, TCP, and SCTP, this is the destination port
                     number given in the respective header.

              Before Open vSwitch 2.5.90, other_config:enable-tunnel-sampling was only  supported
              with  per-bridge  sampling,  and  ignored  otherwise. Open vSwitch 2.5.90 and later
              support other_config:enable-tunnel-sampling for per-bridge and per-flow sampling.

       other_config : virtual_obs_id: optional string
              A string that accompanies each IPFIX flow record.  Its  intended  use  is  for  the
              ``virtual  observation  ID,’’  an identifier of a virtual observation point that is
              locally unique in a virtual network. It describes a location in the virtual network
              where  IP  packets  can  be  observed.  The  maximum  length  is  254 bytes. If not
              specified, the field is omitted from the IPFIX flow record.

              The following enterprise entity reports the specified virtual observation ID:

              virtualObsID:
                     ID: 898, and enterprise ID 6876 (VMware).

                     type: variable-length string.

                     data type semantics: identifier.

                     description: A virtual observation domain ID that is  locally  unique  in  a
                     virtual network.

              This feature was introduced in Open vSwitch 2.5.90.

     Per-Bridge Sampling:

       These  values  affect  only  per-bridge  sampling.  See  above  for  a  description of the
       differences between per-bridge and flow-based sampling.

       sampling: optional integer, in range 1 to 4,294,967,295
              The rate at which packets should be sampled and sent to each target  collector.  If
              not  specified,  defaults  to  400, which means one out of 400 packets, on average,
              will be sent to each target collector.

       obs_domain_id: optional integer, in range 0 to 4,294,967,295
              The IPFIX Observation Domain ID sent  in  each  IPFIX  packet.  If  not  specified,
              defaults to 0.

       obs_point_id: optional integer, in range 0 to 4,294,967,295
              The  IPFIX  Observation  Point ID sent in each IPFIX flow record. If not specified,
              defaults to 0.

       other_config : enable-input-sampling: optional string, either true or false
              By default, Open vSwitch samples and reports flows at bridge port  input  in  IPFIX
              flow records. Set this column to false to disable input sampling.

       other_config : enable-output-sampling: optional string, either true or false
              By  default,  Open vSwitch samples and reports flows at bridge port output in IPFIX
              flow records. Set this column to false to disable output sampling.

     Common Columns:

       The overall purpose of these columns is described under Common Columns at the beginning of
       this document.

       external_ids: map of string-string pairs

Flow_Sample_Collector_Set TABLE

       A  set  of  IPFIX  collectors of packet samples generated by OpenFlow sample actions. This
       table is used only for IPFIX flow-based sampling, not for  per-bridge  sampling  (see  the
       IPFIX table for a description of the two forms).

   Summary:
       id                            integer, in range 0 to 4,294,967,295
       bridge                        Bridge
       ipfix                         optional IPFIX
       Common Columns:
         external_ids                map of string-string pairs

   Details:
       id: integer, in range 0 to 4,294,967,295
              The  ID of this collector set, unique among the bridge’s collector sets, to be used
              as the collector_set_id in OpenFlow sample actions.

       bridge: Bridge
              The bridge into which OpenFlow sample actions can be added to send  packet  samples
              to this set of IPFIX collectors.

       ipfix: optional IPFIX
              Configuration  of  the  set of IPFIX collectors to send one flow record per sampled
              packet to.

     Common Columns:

       The overall purpose of these columns is described under Common Columns at the beginning of
       this document.

       external_ids: map of string-string pairs

AutoAttach TABLE

       Auto  Attach  configuration  within  a  bridge.  The  IETF Auto-Attach SPBM draft standard
       describes a compact method of using IEEE 802.1AB  Link  Layer  Discovery  Protocol  (LLDP)
       together  with a IEEE 802.1aq Shortest Path Bridging (SPB) network to automatically attach
       network devices to individual services in a SPB network.  The  intent  here  is  to  allow
       network applications and devices using OVS to be able to easily take advantage of features
       offered by industry standard SPB networks.

       Auto Attach (AA) uses LLDP to communicate between a directly connected Auto Attach  Client
       (AAC)  and  Auto  Attach  Server (AAS). The LLDP protocol is extended to add two new Type-
       Length-Value tuples (TLVs). The first new TLV supports the ongoing discovery  of  directly
       connected  AA  correspondents. Auto Attach operates by regularly transmitting AA discovery
       TLVs between the AA client and AA server. By exchanging these discovery messages, both the
       AAC  and  AAS  learn  the  system  name  and  system description of their peer. In the OVS
       context, OVS operates as the AA client and the AA server resides on a switch at  the  edge
       of the SPB network.

       Once  AA  discovery  has  been  completed  the AAC then uses the second new TLV to deliver
       identifier mappings from the AAC to the AAS. A  primary  feature  of  Auto  Attach  is  to
       facilitate  the  mapping of VLANs defined outside the SPB network onto service ids (ISIDs)
       defined within the SPM network. By doing so individual external VLANs can be  mapped  onto
       specific  SPB  network  services.  These  VLAN  id  to ISID mappings can be configured and
       managed locally using new options added to the ovs-vsctl command.

       The Auto Attach OVS feature does not provide a full implementation of the  LLDP  protocol.
       Support  for the mandatory TLVs as defined by the LLDP standard and support for the AA TLV
       extensions is provided. LLDP protocol support in OVS can be enabled or disabled on a  port
       by port basis. LLDP support is disabled by default.

   Summary:
       system_name                   string
       system_description            string
       mappings                      map  of integer-integer pairs, key in range 0 to 16,777,215,
                                     value in range 0 to 4,095

   Details:
       system_name: string
              The system_name string is exported in LLDP messages. It  should  uniquely  identify
              the bridge in the network.

       system_description: string
              The  system_description string is exported in LLDP messages. It should describe the
              type of software and hardware.

       mappings: map of integer-integer pairs, key in range 0 to 16,777,215, value in range 0  to
       4,095
              A mapping from SPB network Individual Service Identifier (ISID) to VLAN id.