Provided by: iproute2_5.15.0-1ubuntu2_amd64 bug


       dcb-app  -  show / manipulate application priority table of the DCB (Data Center Bridging)


       dcb [ OPTIONS ] app { COMMAND | help }

       dcb app  {  show  |  flush  }  dev DEV [ default-prio ] [ ethtype-prio ] [ stream-port-
               prio ] [ dgram-port-prio ] [ port-prio ] [ dscp-prio ]

       dcb ets  {  add  |  del  |  replace  }  dev DEV [ default-prio PRIO-LIST ] [ ethtype-prio
               ET-MAP ] [ stream-port-prio PORT-MAP ] [ dgram-port-prio PORT-MAP ] [ port-prio
               PORT-MAP ] [ dscp-prio DSCP-MAP ]


       ET-MAP := [ ET-MAP ] ET-MAPPING





       DSCP-MAPPING := { DSCP | all }:PRIO

       ET := { 0x600 .. 0xffff }

       PORT := { 1 .. 65535 }

       DSCP := { 0 .. 63 }

       PRIO := { 0 .. 7 }


       dcb app is used to configure APP table, or application priority table in the DCB (Data
       Center Bridging) subsystem. The APP table is used to assign priority to traffic based on
       value in one of several headers: EtherType, L4 destination port, or DSCP. It also allows
       configuration of port-default priority that is chosen if no other prioritization rule

       DCB APP entries are 3-tuples of selector, protocol ID, and priority. Selector is an
       enumeration that picks one of the prioritization namespaces. Currently it mostly
       corresponds to configurable parameters described below. Protocol ID is a value in the
       selector namespace. E.g. for EtherType selector, protocol IDs are the individual
       EtherTypes, for DSCP they are individual code points. The priority is the priority that
       should be assigned to traffic that matches the selector and protocol ID.

       The APP table is a set of DCB APP entries. The only requirement is that duplicate entries
       are not added. Notably, it is valid to have conflicting priority assignment for the same
       selector and protocol ID. For example, the set of two APP entries (DSCP, 10, 1) and (DSCP,
       10, 2), where packets with DSCP of 10 should get priority of both 1 and 2, form a well-
       defined APP table. The dcb app tool allows low-level management of the app table by adding
       and deleting individual APP 3-tuples through add and del commands. On the other other
       hand, the command replace does what one would typically want in this situation--first adds
       the new configuration, and then removes the obsolete one, so that only one prioritization
       is in effect for a given selector and protocol ID.


       show   Display all entries with a given selector. When no selector is given, shows all APP
              table entries categorized per selector.

       flush  Remove all entries with a given selector. When no selector is given, removes all
              APP table entries.

       del    Add and, respectively, remove individual APP 3-tuples to and from the DCB APP

              Take the list of entries mentioned as parameter, and add those that are not present
              in the APP table yet. Then remove those entries, whose selector and protocol ID
              have been mentioned as parameter, but not with the exact same priority. This has
              the effect of, for the given selector and protocol ID, causing that the table only
              contains the priority (or priorities) given as parameter.


       The following table shows parameters in a way that they would be used with add, del and
       replace commands. For show and flush, the parameter name is to be used as a simple keyword
       without further arguments.

       default-prio PRIO-LIST
              The priority to be used for traffic the priority of which is otherwise unspecified.
              The argument is a list of individual priorities. Note that default-prio rules are
              configured as triplets (EtherType, 0, PRIO).  dcb app translates these rules to the
              symbolic name default-prio and back.

       ethtype-prio ET-MAP
              ET-MAP uses the array parameter syntax, see dcb(8) for details. Keys are EtherType
              values. Values are priorities to be assigned to traffic with the matching

       stream-port-prio PORT-MAP
       dgram-port-prio PORT-MAP
       port-prio PORT-MAP
              PORT-MAP uses the array parameter syntax, see dcb(8) for details. Keys are L4
              destination port numbers that match on, respectively, TCP and SCTP traffic, UDP and
              DCCP traffic, and either of those. Values are priorities that should be assigned to
              matching traffic.

       dscp-prio DSCP-MAP
              DSCP-MAP uses the array parameter syntax, see dcb(8) for details. Keys are DSCP
              points, values are priorities assigned to traffic with matching DSCP. DSCP points
              can be written either direcly as numeric values, or using symbolic names specified
              in /etc/iproute2/rt_dsfield (however note that that file specifies full 8-bit
              dsfield values, whereas dcb app will only use the higher six bits).  dcb app show
              will similarly format DSCP values as symbolic names if possible. The command line
              option -N turns the show translation off.


       Prioritize traffic with DSCP 0 to priority 0, 24 to 3 and 48 to 6:

       # dcb app add dev eth0 dscp-prio 0:0 24:3 48:6

       Add another rule to configure DSCP 24 to priority 2 and show the result:

       # dcb app add dev eth0 dscp-prio 24:2
       # dcb app show dev eth0 dscp-prio
       dscp-prio 0:0 CS3:2 CS3:3 CS6:6
       # dcb -N app show dev eth0 dscp-prio
       dscp-prio 0:0 24:2 24:3 48:6

       Reconfigure the table so that the only rule for DSCP 24 is for assignment of priority 4:

       # dcb app replace dev eth0 dscp-prio 24:4
       # dcb app show dev eth0 dscp-prio
       dscp-prio 0:0 24:4 48:6

       Flush all DSCP rules:

       # dcb app flush dev eth0 dscp-prio
       # dcb app show dev eth0 dscp-prio


       Exit status is 0 if command was successful or a positive integer upon failure.




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       Petr Machata <>