Introduction to priorities
Priorities include the following types: priorities carried in packets, and priorities locally assigned for scheduling only.
The packet-carried priorities include 802.1p priority, DSCP precedence, IP precedence, EXP, and so on. These priorities have global significance and affect the forwarding priority of packets across the network. For more information about these priorities, see "Appendixes."
The locally assigned priorities only have local significance. They are assigned by the device for scheduling only. These priorities include the following types:
Local precedence—Local precedence is used for queuing. A local precedence value corresponds to an output queue. A packet with higher local precedence is assigned to a higher priority output queue to be preferentially scheduled.
User precedence—User precedence is the precedence the device automatically extracts from a certain priority field of the packet according to its forwarding path. The user precedence represents the 802.1p precedence for Layer 2 packets, the IP precedence for Layer 3 packets, and the EXP precedence for MPLS packets.