Quality of Service (QoS): Managing Bandwidth More Effectively
Using QoS Classifiers To Configure QoS for Outbound Traffic
Effect of
In the QoS
802.1Q Status | Outbound 802.1p |
| Priority |
|
|
Received and Forwarded on a tagged port member of a VLAN. | Unchanged |
Received on an Untagged port member of a VLAN; Forwarded on a | 0 |
tagged port member of a VLAN. |
|
Forwarded on an Untagged port member of a VLAN. | None |
|
|
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
show qos
show qos
For example, suppose that the 000001 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
3.Reconfigure the desired priority for the 000001 codepoint.
4.Either reassign the classifiers to the 00001 codepoint policy or leave them as they were after step 2, above.