An interface's priority is used in the following scenarios:
- When the interface receives untagged VLAN packets, the device forwards the packets based on the interface priority.
- If the interface is configured to trust 802.1p priorities, the device uses the interface priority as the 802.1p priority for the untagged packets received on the interface, and then searches the 802.1p priority mapping table to determine the queue for the untagged packets.