Provided by: openvswitch-switch_2.5.0-0ubuntu1_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.
       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:
         bridges                     set of Bridges
         ssl                         optional SSL
         external_ids : system-id    optional string
         external_ids : xs-system-uuid
                                     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 : n-dpdk-rxqs  optional string, containing an integer, at least 1
         other_config : pmd-cpu-mask
                                     optional string
         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
       Status:
         next_cfg                    integer
         cur_cfg                     integer
         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
       Capabilities:
         datapath_types              set of strings
         iface_types                 set of strings
       Database Configuration:
         manager_options             set of Managers
       Common Columns:
         other_config                map of string-string pairs
         external_ids                map of string-string pairs

   Details:
     Configuration:

       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.  On a Citrix XenServer, this will
              likely be the same as external_ids:xs-system-uuid.

       external_ids : xs-system-uuid: optional string
              The Citrix XenServer  universally  unique  identifier  for  the  physical  host  as
              displayed by xe host-list.

       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.

              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 : n-dpdk-rxqs: optional string, containing an integer, at least 1
              Specifies the maximum number of rx queues to be created for  each  dpdk  interface.
              If  not  specified  or  specified  to 0, one rx queue will be created for each dpdk
              interface by default.

       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 : n-handler-threads: optional string, containing an integer, at least 1
              Specifies the number of threads for software datapaths  to  use  for  handling  new
              flows.    The  default  the  number  of  online  CPU  cores  minus  the  number  of
              revalidators.

              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
              Specifies the number of threads for software  datapaths  to  use  for  revalidating
              flows in the datapath.  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.

     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.

     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  in  the  form  major.minor.tweak,  e.g.  1.2.3.
              Whenever  the  database  schema  is  changed in a non-backward compatible way (e.g.
              deleting a column or a table), major is incremented.  When the database  schema  is
              changed  in  a  backward  compatible  way  (e.g.  adding  a  new  column), minor is
              incremented.  When the database schema is changed  cosmetically  (e.g.  reindenting
              its syntax), tweak is incremented.

              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.
              XenServer or 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.  5.6.100-39265p  on
              XenServer 5.6.100 build 39265.

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

     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 connection should be
              configured.  See the Manager table for more information.

     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 : 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
         protocols                   set  of  strings, one of OpenFlow11, OpenFlow10, OpenFlow13,
                                     OpenFlow12, OpenFlow15, or OpenFlow14
       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
         external_ids : xs-network-uuids
                                     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.   Should  be  alphanumeric and no more than about 8 bytes long.
              Must be unique among the names of ports, interfaces, and bridges on a host.

       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 flow table.  If
              there are no primary controllers, adding one also clears  the  flow  table.   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 the flow table.

       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).

              When more than one 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  flow
              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 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.

       other_config : datapath-id: optional string
              Exactly 16 hex digits to set the OpenFlow datapath ID to a specific value.  May not
              be all-zero.

       other_config : dp-desc: optional string
              Human  readable  description  of datapath.  It it a maximum 256 byte-long free-form
              string to describe the datapath for debugging purposes, e.g. switch3 in room 3120.

       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.

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

              OpenFlow 1.4 is not enabled  by  default  because  its  implementation  is  missing
              features.

              OpenFlow  1.5  has the same risks as OpenFlow 1.4, but it is even more experimental
              because the OpenFlow 1.5 specification is still under development and thus  subject
              to change.  Pass --enable-of15 to ovs-vswitchd to allow OpenFlow 1.5 to be enabled.

     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.  On Citrix XenServer this will commonly  be  the
              same as external_ids:xs-network-uuids.

       external_ids : xs-network-uuids: optional string
              Semicolon-delimited  set  of  universally unique identifier(s) for the network with
              which  this  bridge  is  associated  on  a  Citrix  XenServer  host.   The  network
              identifiers are RFC 4122 UUIDs as displayed by, e.g., xe network-list.

       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 2048.  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,    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
         other_config : priority-tags
                                     optional string, either true or false
       Bonding Configuration:
         bond_mode                   optional  string,  one  of  active-backup,  balance-tcp,  or
                                     balance-slb
         other_config : bond-hash-basis
                                     optional string, containing an integer
         Link Failure Detection:
            other_config : bond-detect-mode
                                     optional string, either miimon or carrier
            other_config : bond-miimon-interval
                                     optional string, containing an integer
            bond_updelay             integer
            bond_downdelay           integer
         LACP Configuration:
            lacp                     optional string, one of active, passive, or off
            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 slow or fast
            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 10,000
         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  disabled,  forwarding,  learning,
                                     listening, or blocking
            status : stp_sec_in_state
                                     optional string, containing an integer, at least 0
            status : stp_role        optional string, one of designated, alternate, 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-port-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 Backup, Designated, Alternate, Root,
                                     or Disabled
            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
         external_ids : fake-bridge-id-*
                                     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.  Should be alphanumeric and no more than about 8 bytes long.  May be the
              same as the interface name, for non-bonded ports.  Must otherwise be  unique  among
              the names of ports, interfaces, and bridges on a host.

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

     VLAN Configuration:
       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.

       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, 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.

       other_config : priority-tags: optional string, either true or false
              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 true to enable priority-tagged frames on a port.

              Regardless of this setting, Open vSwitch omits the 802.1Q header on output if  both
              the VLAN ID and priority would be zero.

              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 slaves based on source MAC  address  and  output  VLAN,
                     with periodic rebalancing as traffic patterns change.

              active-backup
                     Assigns  all  flows  to  one  slave, failing over to a backup slave when the
                     active slave 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  slaves  based on L2, L3, and L4 protocol information
                     such as destination MAC address, IP address, and TCP port.

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

       bond_mode: optional string, one of active-backup, balance-tcp, or balance-slb
              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  slaves  in  load  balanced
              bonds.   When  changed,  all  flows will be assigned different hash values possibly
              causing slave selection decisions to change.  Does not affect bonding  modes  which
              do not employ load balancing such as active-backup.

     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 miimon or carrier
              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, passive, or off
              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 slow or fast
              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 10,000
              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 disabled, forwarding, learning, listening, or
       blocking
              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 designated, alternate, 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-port-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 Backup, Designated, Alternate, Root,
       or Disabled
              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.

       external_ids : fake-bridge-id-*: 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-xs-network-uuids.

       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 slave.

     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 : key               optional string
         options : tos               optional string
         options : ttl               optional string
         options : df_default        optional string, either true or false
         Tunnel Options: vxlan only:
            options : exts           optional string
         Tunnel Options: gre, ipsec_gre, geneve, and vxlan:
            options : csum           optional string, either true or false
         Tunnel Options: ipsec_gre only:
            options : peer_cert      optional string
            options : certificate    optional string
            options : private_key    optional string
            options : psk            optional string
       Patch Options:
         options : peer              optional string
       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
         mtu                         optional integer
         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
       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_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 Status:
            bfd_status : state       optional string, one of down, init, up, or admin_down
            bfd_status : forwarding  optional string, either true or false
            bfd_status : diagnostic  optional string
            bfd_status : remote_state
                                     optional string, one of down, init, up, or admin_down
            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 : xs-vif-uuid  optional string
         external_ids : xs-network-uuid
                                     optional string
         external_ids : vm-id        optional string
         external_ids : xs-vm-uuid   optional string
       VLAN Splinters:
         other_config : enable-vlan-splinters
                                     optional string, either true or false
       Auto Attach Configuration:
         lldp : enable               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 and no more than about 8 bytes long.  May
              be the same as the port name, for non-bonded ports.  Must otherwise be unique among
              the names of ports, interfaces, and bridges on a host.

       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  slave
                     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.

       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.

              geneve An                  Ethernet                   over                   Geneve
                     (http://tools.ietf.org/html/draft-ietf-nvo3-geneve-00)   IPv4   tunnel.    A
                     description of how to match and set Geneve  options  can  be  found  in  the
                     ovs-ofctl manual page.

              gre    An Ethernet over RFC 2890 Generic Routing Encapsulation over IPv4 tunnel.

              ipsec_gre
                     An  Ethernet  over  RFC  2890  Generic Routing Encapsulation over IPv4 IPsec
                     tunnel.

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

                     Open vSwitch uses 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  http://www.ietf.org/archive/id/draft-davie-
                     stt-06.txt All traffic uses a default destination port of 7471. STT is  only
                     available in kernel datapath on kernel 3.5 or newer.

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

              null   An ignored interface. Deprecated and slated for removal in February 2013.

     Tunnel Options:
       These  options  apply  to  interfaces with type of geneve, gre, ipsec_gre, vxlan, lisp and
       stt.

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

              •      An IPv4  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  field.   When  sending  packets  to a
                     remote_ip=flow tunnel, the flow actions  must  explicitly  set  the  tun_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 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 field.   When
                     sending  packets  to a local_ip=flow tunnel, the flow actions may explicitly
                     set the tun_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 field for matching in the flow table.

       options : in_key: optional string
              Optional.  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-ofctl
                     manual  page  contains  additional  information  about  matching  fields  in
                     OpenFlow flows.

       options : out_key: optional string
              Optional.  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-ofctl manual page contains additional information about
                     the Nicira OpenFlow vendor extensions.

       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.

     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 field description of
                     tun_gbp_id  and  tun_gbp_flags  in  ovs-ofctl(8) for additional information.
                     (https://tools.ietf.org/html/draft-smith-vxlan-group-policy)

     Tunnel Options: gre, ipsec_gre, geneve, and vxlan:
       gre, ipsec_gre, geneve, 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 supports 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.

              This option is supported for ipsec_gre, but not useful because  GRE  checksums  are
              weaker than, and redundant with, IPsec payload authentication.

     Tunnel Options: ipsec_gre only:
       Only ipsec_gre interfaces support these options.

       options : peer_cert: optional string
              Required   for   certificate   authentication.   A  string  containing  the  peer’s
              certificate in PEM format.  Additionally the host’s certificate must  be  specified
              with the certificate option.

       options : certificate: optional string
              Required  for  certificate  authentication.   The  name  of a PEM file containing a
              certificate that will be presented to the peer during authentication.

       options : private_key: optional string
              Optional for certificate authentication.  The name of a  PEM  file  containing  the
              private  key associated with certificate.  If certificate contains the private key,
              this option may be omitted.

       options : psk: optional string
              Required for  pre-shared  key  authentication.   Specifies  a  pre-shared  key  for
              authentication that must be identical on both sides of the tunnel.

     Patch Options:
       Only patch interfaces support these options.

       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.

     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.

       mtu: optional integer
              The  MTU  (maximum transmission unit); i.e. 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.

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

       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 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.

     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  is  currently implemented only on Linux.  The Linux implementation uses a simple
       ``token bucket’’ approach:

              •      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.

       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_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 1000 kb.  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 10% of  ingress_policing_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.  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.

     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 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 down, init, up, or admin_down
              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 down, init, up, or admin_down
              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.  For a Citrix XenServer hypervisor, these values
       are UUIDs in RFC 4122 format.  Other hypervisors may use other formats.

       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.   For Citrix XenServer, this is the value of the MAC field
              in the VIF record for this interface.

       external_ids : iface-id: optional string
              A system-unique identifier for the interface.  On XenServer, this will commonly  be
              the same as external_ids:xs-vif-uuid.

       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 XenServer has 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 : xs-vif-uuid: optional string
              The virtual interface associated with this interface.

       external_ids : xs-network-uuid: optional string
              The virtual network to which this interface is attached.

       external_ids : vm-id: optional string
              The VM to which this interface belongs. On XenServer, this  will  be  the  same  as
              external_ids:xs-vm-uuid.

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

     VLAN Splinters:
       The  ``VLAN  splinters’’  feature  increases Open vSwitch compatibility with buggy network
       drivers in old versions of Linux that do not properly support VLANs when VLAN devices  are
       not used, at some cost in memory and performance.

       When  VLAN  splinters  are  enabled on a particular interface, Open vSwitch creates a VLAN
       device for each in-use VLAN.  For sending traffic tagged with a VLAN on the interface,  it
       substitutes  the VLAN device.  Traffic received on the VLAN device is treated as if it had
       been received on the interface on the particular VLAN.

       VLAN splinters consider a VLAN to be in use if:

              •      The VLAN is the tag value in any Port record.

              •      The VLAN is listed within the  trunks  column  of  the  Port  record  of  an
                     interface  on  which  VLAN  splinters are enabled.  An empty trunks does not
                     influence the in-use VLANs:  creating  4,096  VLAN  devices  is  impractical
                     because it will exceed the current 1,024 port per datapath limit.

              •      An OpenFlow flow within any bridge matches the VLAN.

       The  same  set  of  in-use  VLANs  applies  to every interface on which VLAN splinters are
       enabled.  That is, the set is not chosen separately for each interface but  selected  once
       as the union of all in-use VLANs based on the rules above.

       It  does not make sense to enable VLAN splinters on an interface for an access port, or on
       an interface that is not a physical port.

       VLAN splinters are deprecated.  When broken device drivers are  no  longer  in  widespread
       use, we will delete this feature.

       other_config : enable-vlan-splinters: optional string, either true or false
              Set to true to enable VLAN splinters on this interface.  Defaults to false.

              VLAN  splinters  increase  kernel and userspace memory overhead, so do not use them
              unless they are needed.

              VLAN splinters do not support  802.1p  priority  tags.   Received  priorities  will
              appear  to  be  0, regardless of their actual values, and priorities on transmitted
              packets will also be cleared to 0.

     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.

     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 refuse or evict
         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 refuse or evict
              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 nicira-ext.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,  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
       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.

       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 100 Mbps.

     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
       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.

     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.

       Open vSwitch supports two kinds of OpenFlow controllers:

              Primary controllers
                     This is the kind of controller envisioned by the OpenFlow 1.0 specification.
                     Usually, a primary controller implements a network policy by  taking  charge
                     of the switch’s flow table.

                     Open  vSwitch  initiates  and  maintains  persistent  connections to primary
                     controllers, retrying the connection each  time  it  fails  or  drops.   The
                     fail_mode column in the Bridge table applies to primary controllers.

                     Open  vSwitch  permits  a  bridge to have any number of primary controllers.
                     When multiple controllers are configured, Open vSwitch connects  to  all  of
                     them  simultaneously.   Because  OpenFlow  1.0 does not specify how multiple
                     controllers coordinate in interacting with a single switch,  more  than  one
                     primary   controller  should  be  specified  only  if  the  controllers  are
                     themselves designed to coordinate  with  each  other.   (The  Nicira-defined
                     NXT_ROLE OpenFlow vendor extension may be useful for this.)

              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.

                     Open vSwitch listens for incoming connections from service controllers.  The
                     service  controllers  initiate  and,  if necessary, maintain the connections
                     from their end.  The fail_mode column in the Bridge table does not apply  to
                     service controllers.

                     Open vSwitch supports configuring any number of service controllers.

       The target determines the type of controller.

   Summary:
       Core Features:
         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_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 slave, other, or master
         status : last_error         optional string
         status : state              optional  string,  one of ACTIVE, VOID, CONNECTING, IDLE, or
                                     BACKOFF
         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:

       target: string
              Connection method for controller.

              The following connection methods are currently supported for primary controllers:

              ssl:ip[:port]
                     The specified SSL port on the host at the given ip, which must be  expressed
                     as an IP address (not a DNS name).  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:ip[:port]
                     The  specified TCP port on the host at the given ip, which must be expressed
                     as an IP address (not a DNS name), where ip can be IPv4 or IPv6 address.  If
                     ip 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 connection methods are currently supported for service controllers:

              pssl:[port][:ip]
                     Listens for SSL connections on the specified TCP port.  If ip, which must be
                     expressed as an IP address (not a DNS name), is specified, then  connections
                     are  restricted to the specified local IP address (either IPv4 or IPv6).  If
                     ip is an IPv6 address, wrap it in square brackets, e.g. pssl:6653:[::1].

                     If port is not specified, it defaults to 6653.  If ip 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][:ip]
                     Listens for connections on the specified TCP port.  If  ip,  which  must  be
                     expressed  as an IP address (not a DNS name), is specified, then connections
                     are restricted to the specified local IP address (either IPv4 or IPv6).   If
                     ip  is an IPv6 address, wrap it in square brackets, e.g. ptcp:6653:[::1]. If
                     ip 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_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 slave, other, or master
              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 master  controller
                     at  a  time.   When  a  controller configures itself as master, any existing
                     master is demoted to the slave role.

              slave  Allows the controller read-only access to OpenFlow  features.   Attempts  to
                     modify  the flow table will be rejected with an error.  Slave 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, VOID, CONNECTING, IDLE, or BACKOFF
              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, VOID, CONNECTING,  IDLE,  or
                                     BACKOFF
         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:ip[:port]
                     The  specified SSL port on the host at the given ip, which must be expressed
                     as an IP address (not a DNS name).  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:ip[:port]
                     The specified TCP port on the host at the given ip, which must be  expressed
                     as an IP address (not a DNS name), where ip can be IPv4 or IPv6 address.  If
                     ip 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][:ip]
                     Listens for SSL connections on the specified TCP port.  Specify 0  for  port
                     to  have  the  kernel  automatically choose an available port.  If ip, which
                     must be expressed as an IP address (not a  DNS  name),  is  specified,  then
                     connections are restricted to the specified local IP address (either IPv4 or
                     IPv6 address).  If ip is an IPv6 address,  wrap  in  square  brackets,  e.g.
                     pssl:6640:[::1].   If  ip 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][:ip]
                     Listens for connections on the specified TCP port.  Specify 0  for  port  to
                     have  the  kernel automatically choose an available port.  If ip, which must
                     be expressed as  an  IP  address  (not  a  DNS  name),  is  specified,  then
                     connections are restricted to the specified local IP address (either IPv4 or
                     IPv6 address).  If ip is an IPv6 address, wrap it in square  brackets,  e.g.
                     ptcp:6640:[::1].   If  ip  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:

       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, VOID, CONNECTING, IDLE, or BACKOFF
              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.

              When  multiple  connections  are  active, status columns and key-value pairs (other
              than this one) report the status of one arbitrarily chosen connection.

       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  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

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
              Name of the network device whose IP address  should  be  reported  as  the  ``agent
              address’’  to  collectors.   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 any of these  ways,  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-ofctl(8) 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
       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-tunnel-sampling
                                     optional string, either true or false
         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.

     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-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 disabled 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, 0x05 IPsec+GRE, 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.

       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.