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Priority Mapping Configuration
When configuring priority mapping, go to these sections for information you are interested in:
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Priority Mapping Overview
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Configuring a Priority Mapping Table
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Configuring the Priority for a Port
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Configuring the Trusted Precedence Type for a Port
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Displaying and Maintaining Priority Mapping
Priority Mapping Overview
Introduction to Priority Mapping
When a packet enters a network, it will be marked with a certain value, which indicates the scheduling
weight or forwarding priority of the packet. Then, the intermediate nodes in the network process the
packet according to the priority.
When a packet enters a device, the device assigns to the packet a set of predefined parameters
(including the 802.1p priority, DSCP values, IP precedence, and local precedence).
Concepts
For more information about 802.11e precedence, 802.1p precedence, DSCP values, and EXP values,
refer to
Packet Precedences
.
Local precedence is a locally significant precedence that the device assigns to a packet. A local
precedence value corresponds to an output queue. Packets with the highest local precedence are
processed preferentially.
Depending on whether a received packet is 802.1q-tagged, the switch marks it with priority as follows:
1) For an 802.1q-untagged packet
When a packet carrying no 802.1q tag reaches a port, the switch uses the port priority as the 802.1p
precedence value of the received packet, searches for the local precedence value corresponding to the
port priority of the receiving port in the 802.1p-precedence-to-local-precedence mapping table, assigns
the local precedence value to the packet, and enqueues the packet according to the local precedence
value.
2) For an 802.1q-tagged packet
When an 802.1q tagged packet reaches the port of a switch, you can specify a priority trust mode for the
port, trusting port priority or trusting packet priority.
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Trusting packet priority
