dcb-app(8) — Linux manual page


DCB-APP(8)                        Linux                       DCB-APP(8)

NAME         top

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

SYNOPSIS         top

       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 ] [ pcp-prio ]

       dcb app  {  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 ] [ pcp-prio PCP-MAP ]


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





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



       ET := { 0x600 .. 0xffff }

       PORT := { 1 .. 65535 }

       DSCP := { 0 .. 63 }

       PCP := { 0(nd/de) .. 7(nd/de) }

       PRIO := { 0 .. 7 }

DESCRIPTION         top

       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 applies.

       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 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

COMMANDS         top

       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 table.

              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.

PARAMETERS         top

       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

       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 EtherType.

       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 directly as numeric values, or using
              symbolic names specified in /etc/iproute2/rt_dsfield
              (however note that the 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.

       pcp-prio PCP-MAP
              PCP-MAP uses the array parameter syntax, see dcb(8) for
              details. Keys are PCP/DEI. Values are priorities assigned
              to traffic with matching PCP/DEI. PCP/DEI values are
              written as a combination of numeric- and symbolic values,
              to accommodate for both. PCP always in numerical form e.g
              0 .. 7 and DEI in symbolic form e.g 'de' (drop-eligible),
              indicating that the DEI bit is 1 or 'nd' (not-drop-
              eligible), indicating that the DEI bit is 0.  In
              combination 2de:1 translates to a mapping of PCP=2 and
              DEI=1 to priority 1.

EXAMPLE & USAGE         top

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

       # 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

       # 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 -N 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

       Add a rule to map traffic with PCP 1 and DEI 0 to priority 1 and
       PCP 2 and DEI 1 to priority 2:

       # dcb app add dev eth0 pcp-prio 1nd:1 2de:2
       # dcb app show dev eth0 pcp-prio
       pcp-prio 1nd:1 2de:2

EXIT STATUS         top

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

SEE ALSO         top


REPORTING BUGS         top

       Report any bugs to the Network Developers mailing list
       <netdev@vger.kernel.org> where the development and maintenance is
       primarily done.  You do not have to be subscribed to the list to
       send a message there.

AUTHOR         top

       Petr Machata <me@pmachata.org>

COLOPHON         top

       This page is part of the iproute2 (utilities for controlling
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iproute2                     6 December 2020                  DCB-APP(8)

Pages that refer to this page: dcb(8)dcb-apptrust(8)dcb-rewr(8)