Technical Documentation

Defining Code Point Aliases for Bit Patterns

To define a code-point alias, include the code-point-aliases statement at the [edit class-of-service] hierarchy level:

[edit class-of-service]code-point-aliases {(dscp | dscp-ipv6 | exp | ieee-802.1 | inet-precedence) {alias-name bit-pattern;}}

The CoS marker types are as follows:

  • dscp—Handles incoming IPv4 packets.
  • dscp-ipv6—Handles incoming IPv6 packets. For more information, see Applying DSCP IPv6 Classifiers.
  • exp—Handles MPLS packets using Layer 2 headers.
  • ieee-802.1—Handles Layer 2 CoS.
  • inet-precedence—Handles incoming IPv4 packets. IP precedence mapping requires only the upper three bits of the DSCP field.

For example, you might configure the following aliases:

[edit class-of-service]code-point-aliases {dscp {my1 110001;my2 101110;be 000001;cs7 110000;}}

This configuration produces the following mapping:


user@host> show class-of-service code-point-aliases dscp
Code point type: dscp
Alias              Bit pattern
ef/my2             101110
af11               001010
af12               001100
af13               001110
af21               010010
af22               010100
af23               010110
af31               011010
af32               011100
af33               011110
af41               100010
af42               100100
af43               100110
be                 000001
cs1                001000
cs2                010000
cs3                011000
cs4                100000
cs5                101000
nc1/cs6/cs7        110000
nc2                111000
my1                110001

The following notes explain certain results in the mapping:

  • my1 110001:
    • 110001 was not mapped to anything before, and my1 is a new alias.
    • Nothing in the default mapping table is changed by this statement.
  • my2 101110:
    • 101110 is now mapped to my2 as well as ef.
  • be 000001:
    • be is now mapped to 000001.
    • The old value of be, 000000, is not associated with any alias. Packets with this DSCP value are now mapped to the default forwarding class.
  • cs7 110000:
    • cs7 is now mapped to 110000, as well as nc1 and cs6.
    • The old value of cs7, 111000, is still mapped to nc2.

Related Topics


Published: 2010-07-16

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