Which Priority Does an Interface Trust?
An interface can be configured to trust DSCP priorities and 802.1p priorities simultaneously, or trust IP precedences and 802.1p priorities simultaneously. When an interface is configured to trust DSCP priorities and 802.1p priorities simultaneously, or trust IP precedences and 802.1p priorities simultaneously, the interface:
- Trusts DSCP priorities or IP priorities if IPv4 packets are received.
- Trusts 802.1p priorities if VLAN packets are received.
The DSCP priority and IP precedence use different bits of the ToS field; therefore, an interface cannot be configured to trust DSCP priorities and IP precedences simultaneously.