Users Guide

Table 73. Default DSCP to Queue Mapping
DSCP/CP bit range (in
hexadecimal)
DSCP Definition Traditional IP
Precedence
Internal Queue ID DSCP/CP decimal
range
111xxx Network Control 7 56–63
110xxx Internetwork Control 6 48–55
101xxx EF (Expedited
Forwarding)
CRITIC/ECP 5 40–47
100xxx AF4 (Assured
Forwarding)
Flash Override 4 32–39
011xxx AF3 Flash 3 24–31
010xxx AF2 Immediate 2 16–23
001xxx AF1 Priority 1 8–15
000xxx BE (Best Effort) Best Effort 0 0–7
• Enable the trust DSCP feature.
POLICY-MAP-IN mode
trust diffserv
Honoring dot1p Values on Ingress Packets
In an input QoS policy, you can configure the system to honor dot1p values on ingress packets using the Trust dot1p feature.
The following table specifies the queue to which the classified traffic is sent based on the dot1p value.
Table 74. Default dot1p to Queue Mapping
Packet dot1p on Ingress Packet Queue ID
0 1
1 0
2 2
3 3
4 4
5 5
6 6
7 7
The dot1p value is also honored for frames on the default VLAN. For more information, refer to Priority-Tagged Frames on the
Default VLAN.
• Enable the trust dot1p feature.
POLICY-MAP-IN mode
trust dot1p
Mapping dot1p Values to Service Queues
All traffic is by default mapped to the same queue, Queue 0.
If you honor dot1p on ingress, you can create service classes based the queueing strategy in Honoring dot1p Values on Ingress
Packets. You may apply this queuing strategy globally by entering the following command from CONFIGURATION mode.
• All dot1p traffic is mapped to Queue 0 unless you enable service-class dynamic dot1p on an interface or globally.
Quality of Service (QoS) 771