Dell Force10 MXL Blade - Page 428

426 | Quality of Service (QoS)
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3. Apply the input policy map to an interface.
Apply a Class-Map or Input QoS Policy to a Queue
To assign an input QoS policy to a queue, use the service-queue command from POLICY-MAP-IN mode.
Apply an Input QoS Policy to an Input Policy Map
To apply an input QoS policy to an input policy map, use the policy-aggregate command from
POLICY-MAP-IN mode.
Honor DSCP Values on Ingress Packets
FTOS provides the ability to honor DSCP values on ingress packets using the trust DSCP feature. To
enable the trust DSCP feature, use the
trust diffserv command from POLICY-MAP-IN mode. Table 24-3
lists the standard DSCP definitions and indicates to which queues FTOS maps the DSCP values. When you
configure trust DSCP, the matched packets and matched bytes counters are not incremented in the
show qos
statistics
command.
Table 24-3. Default DSCP to Queue Mapping
Note: Packets with DSCP value of 63 are dropped.
DSCP/CP
hex range
(XXX) DSCP Definition Traditional IP Precedence
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