Setup Guide

Honoring DSCP Values on Ingress Packets
You can congure the ability to honor DSCP values on ingress packets by using the Trust DSCP feature.
The following table lists the standard DSCP denitions and indicates how DSCP values are mapped to queues. When you congure trust
DSCP, the matched packets and matched bytes counters are not incremented in the show qos statistics.
Table 83. Default DSCP to Queue Mapping
DSCP/CP bit range (in
hexadecimal)
DSCP Denition 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 Eort) Best Eort 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 congure the system to honor dot1p values on ingress packets using the Trust dot1p feature.
The following table species the queue to which the classied trac is sent based on the dot1p value.
Table 84. 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
856
Quality of Service (QoS)