Changing an entry in the DSCP table

Last Updated : Nov 06, 2012 |

Procedure

  1. Enter the context of a QoS list.
  2. Enter dscp-table followed by the number of the DSCP value for which you want to change its composite operation.
  3. Enter composite-operation followed by the name of the composite operation you want to execute for packets with the specified DSCP value.

Result

The following commands specify the pre-configured composite operation CoS5 for DSCP table entry 33 in QoS list 401. Every packet with DSCP equal to 33 is assigned CoS priority 5.

Gxxx-001# ip qos-list 401
Gxxx-001(QoS 401)# dscp-table 33
Gxxx-001(QoS 401/dscp 33)# composite-operation CoS5
Done!

The following commands create a new composite operation called dscp5 and assign the new composite operation to DSCP table entry 7 in QoS list 402. Every packet with DSCP equal to 7 is assigned a new DSCP value of 5.

Gxxx-001(super)# ip qos-list 402
Gxxx-001(super/QoS 402)# composite-operation 12
Gxxx-001(super/QoS 402/CompOp 12)# name dscp5
Done!
Gxxx-001(super/QoS 402/CompOp 12)# dscp 5
Done!
Gxxx-001(super/QoS 402/CompOp 12)# cos No-Change
Done!
Gxxx-001(super/QoS 402/CompOp 12)# exit
Gxxx-001(super/QoS 402)# dscp-table 7
Gxxx-001(super/QoS 402/dscp 7)# composite-operation dscp5
Done!

Composite operation dscp5 changes the mapping of packets entering the router with a DSCP values of 7. DSCP value 5 is most likely to be mapped to a different CoS, making these packets subject to a different set of behavioral rules.