Reference Guide

Quality of Service (QoS) | 729
Dell Networking OS provides the ability to honor DSCP values on ingress packets using Trust DSCP
feature. Enable this feature using the command
trust diffserv from POLICY-MAP-IN mode. Table 40-4 lists
the standard DSCP definitions, and indicates to which queues Dell Networking OS maps DSCP values.
When Trust DSCP is configured the matched packets and matched bytes counters are not incremented in
show qos statistics.
Table 40-4. Default DSCP to Queue Mapping
Honoring dot1p values on ingress packets:
Dell Networking OS provides the ability to honor dot1p values on ingress packets with the Trust dot1p
feature. Enable Trust dot1p using the command
trust dot1p from POLICY-MAP-IN mode. Table 40-5
specifies the queue to which the classified traffic is sent based on the dot1p value.
The dot1p value is also honored for frames on the default VLAN; see Priority-tagged Frames on the
Default VLAN.
DSCP/CP
hex range (XXX) DSCP Definition Traditional IP Precedence
S5000
Internal
Queue ID
DSCP/CP
decimal
111XXX Network Control 3
48–63
110XXX Internetwork Control 3
101XXX EF (Expedited
Forwarding)
CRITIC/ECP 2
32–47
100XXX AF4 (Assured
Forwarding)
Flash Override 2
011XXX AF3 Flash 1
16–31
010XXX AF2 Immediate 1
001XXX AF1 Priority 0
0–15
000XXX BE (Best Effort) Best Effort 0
Table 40-5. Default dot1p to Queue Mapping
dot1p
S5000
Queue ID
01
10
20
31
42
52
63
73