By default, 802.1p priority information is not replaced or manipulated, and the information observed on ingress is preserved when forwarding the frame. This behavior is not affected by the switching or routing configuration of the switch. However, the switch is capable of inserting and/or overwriting 802.1p priority information when it transmits an 802.1Q tagged frame as described below.
If you are using ACL-based traffic groups, you can use the replace-dot1p action modifier to replace the ingress 802.1p priority value with the 802.1p priority value of the egress QoS profile as listed in the following table. To specify a specific 802.1p priority value on egress, use the replace-dot1p-value action modifier.
Note
If you are using ACL-based traffic groups, you must use ACL action modifiers to replace the 802.1p priority. Traffic that meets any ACL match conditions is not subject to non-ACL-based 802.1p priority replacement.For non-ACL-based traffic groups, you can enable or disable 802.1p priority replacement on specific ingress ports. When 802.1p priority replacement is enabled, the default egress 802.1p priority value is set to the priority value of the egress QoS profile as listed in Default Queue-to-802.1p Priority Replacement Value.
| Egress QoS Profile | 802.1p Priority Replacement Value |
|---|---|
| QP1 | 0 |
| QP2 | 1 |
| QP3 | 2 |
| QP4 | 3 |
| QP5 | 4 |
| QP6 | 5 |
| QP7 | 6 |
| QP8 | 7 |
To enable 802.1p priority replacement on egress, use the following command:
enable dot1p replacement ports [port_list | all]
Note
The port in this command is the ingress port.To disable this feature, use the following command:
disable dot1p replacement ports [port_list | all]
Note
If only DiffServ traffic groups are enabled, then 802.1p priority enforcement for 802.1q tagged packets continues for non-IP packets using the default 802.1p map shown in the following table.
Only QP1 and QP8 exist by default; you must create QP2 to QP7 (QP2 to QP5 in a SummitStack). If you have not created these QPs, the replacement feature will not take effect.
When DiffServ examination is enabled on 1 Gigabit Ethernet ports, 802.1p replacement is enabled and cannot be disabled. The ingress 802.1p value is replaced with the 802.1p value assigned to the egress QoS profile.