Note on changing a priority setting

If a QoS classifier is using a policy (codepoint and associated priority) in the DSCP Policy table, you must delete or change this usage before you can change the priority setting on the codepoint. Otherwise the switch blocks the change and displays this message: 

Cannot modify DSCP Policy < codepoint > - in use by other
qos rules.

In this case, use show qos <classifier> to identify the specific classifiers using the policy you want to change; that is:

show qos device-priority

show qos port-priority

show qos tcp-udp-port-priority

show qos vlan-priority

show qos type-of-service

For example, suppose that the 000001 (dscp 1) codepoint has a priority of 6, and several classifiers use the 000001 codepoint to assign a priority to their respective types of traffic. If you wanted to change the priority of codepoint 000001, you would do the following:

  1. Identify which QoS classifiers use the codepoint.

  2. Change the classifier configurations by assigning them to a different DSCP policy, or to an 802.1p priority, or to No-override.

  3. Reconfigure the desired priority for the 000001 (dscp 1) codepoint.

  4. Either reassign the classifiers to the 000001 (dscp 1) codepoint policy or leave them as they were after step 2, above.