Dell Force10 S55T S55 Configuration Guide FTOS 8.3.5.3 - Page 573

Create Input Policy Maps There are two types of input policy-maps: Layer 3 and Layer 2. 1. Create a Layer 3 input policy map using the command policy-map-input from CONFIGURATION mode. Create a Layer 2 input policy map by specifying the keyword layer2 with the policy-map-input command. 2. Once you create an input policy map, do one or more of the following: • Apply a class-map or input QoS policy to a queue • Apply an input QoS policy to an input policy map • Honor DSCP values on ingress packets • Honoring dot1p values on ingress packets 3. Apply the input policy map to an interface. See page 60. FTOS Behavior: On ExaScale, FTOS cannot classify protocol traffic on a Layer 2 interface using Layer 3 policy map. The packets always take the default queue, Queue 0, and cannot be rate-policed. Apply a class-map or input QoS policy to a queue Assign an input QoS policy to a queue using the command service-queue from POLICY-MAP-IN mode. Apply an input QoS policy to an input policy map Apply an input QoS policy to an input policy map using the command policy-aggregate from POLICY-MAP-IN mode. Honor DSCP values on ingress packets FTOS 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 31-5 lists the standard DSCP definitions, and indicates to which queues FTOS maps DSCP values. When Trust DSCP is configured the matched packets and matched bytes counters are not incremented in show qos statistics. Table 31-5. Default DSCP to Queue Mapping DSCP/CP hex range (XXX)xxx DSCP Definition 111XXX 110XXX 101XXX 100XXX EF (Expedited Forwarding) AF4 (Assured Forwarding) Traditional IP Precedence Network Control Internetwork Control CRITIC/ECP E-Series Internal Queue ID 7 6 5 Flash Override 4 C-Series Internal Queue ID 3 3 2 2 S-Series Internal DSCP/CP Queue ID decimal 3 48-63 3 2 32-47 2 Quality of Service | 573