Priority Mapping Results Are Incorrect
Common Causes
- On the outbound interface, packets do not enter queues corresponding to priorities of packets.
- The priority types trusted by the inbound and outbound interfaces do not meet service requirements.
- The priority mappings configured in the DiffServ domains bound to the inbound and outbound interfaces do not meet service requirements.
- There are configurations affecting priority mapping on the inbound and outbound interfaces.
Procedure
- Check whether packets enter the correct queues on the outbound interface.
Run the display qos queue statistics interface interface-type interface-number command to check whether packets enter the correct queues on the outbound interface.
- If packets enter incorrect queues, locate the fault. For details, see Packets Enter Incorrect Queues.
- If packets enter the correct queues, go to step 2.
- Check whether the priority types trusted by the inbound and outbound interface are correct.
Run the display this command in the inbound or outbound interface view to check whether the trusted priority type set using the trust command is correct. (If the trust command is not configured, the system trusts the 802.1p priority in the outer VLAN tag by default.)
- If the trusted priority type is incorrect, run the trust command to specify the correct priority type.
- If the trusted priority type is correct, go to step 3.
- Check whether the priority mapping configuration in the DiffServ domain bound to the inbound or outbound interface is correct.
Run the display this command in the inbound or outbound interface view to check whether the trust upstream command is configured. If this command is not configured, the system trusts the DiffServ domain default by default.
Run the display diffserv domain ds-domain-name command to check whether the mappings between PHBs/colors and packet priorities are correct.
- If the priority mappings are incorrect, run the ip-dscp-outbound, mpls-exp-outbound or 8021p-outbound command to correctly configure the mappings between PHBs/colors and packet priorities.
- If the priority mappings are correct, go to step 4.
- Check whether there are configurations affecting priority mapping on the inbound and outbound interfaces.The following configurations affect priority mapping on the inbound and outbound interfaces:
- If the qos phb marking 8021p disable command is configured, the system does not perform PHB mapping for outgoing packets on an interface.
- If the trust upstream none command is configured, the system does not perform PHB mapping for outgoing packets on an interface.
- If packets match a traffic policy that is applied to the inbound or outbound direction (using the traffic-policy command) and contains a remark 8021p or remark dscp traffic behavior, the packet priority is re-marked.
Run the display this command in the inbound or outbound interface view to check for the preceding configurations. If such configurations are found, delete or modify them.