Dell C1048P Port Extender Networking Configuration Guide for the C9000 Series - Page 865

class-map match-any class_dscp_40 match ip access-group dscp_40_non_ecn set-color yellow match ip access-group dscp_40 class-map match-any class_dscp_50 match ip access-group dscp_50_non_ecn set-color yellow match ip access-group dscp_50 policy-map-input pmap_dscp_40_50 service-queue 2 class-map class_dscp_40 service-queue 3 class-map class_dscp_50 The second example shows how to achieve the desired configuration by specifying ECN match criteria to classify ECN-capable packets: ip access-list standard dscp_50_ecn seq 5 permit any dscp 50 ecn 1 seq 10 permit any dscp 50 ecn 2 seq 15 permit any dscp 50 ecn 3 ip access-list standard dscp_40_ecn seq 5 permit any dscp 40 ecn 1 seq 10 permit any dscp 40 ecn 2 seq 15 permit any dscp 40 ecn 3 ip access-list standard dscp_50_non_ecn seq 5 permit any dscp 50 ecn 0 ip access-list standard dscp_40_non_ecn seq 5 permit any dscp 40 ecn 0 class-map match-any class_dscp_40 match ip access-group dscp_40_non_ecn set-color yellow match ip access-group dscp_40_ecn class-map match-any class_dscp_50 match ip access-group dscp_50_non_ecn set-color yellow match ip access-group dscp_50_ecn policy-map-input pmap_dscp_40_50 service-queue 2 class-map class_dscp_40 service-queue 3 class-map class_dscp_50 Using A Configurable Weight for WRED and ECN The switch supports a user-configurable weight that determines the average queue size used in WRED and Explicit Congestion Notification (ECN) operation on front-end I/O and backplane interfaces. By default, the switch uses a weight factor of 0 (instantaneous ECN marking), which results in packet dropping during times of network congestion based on the configured minimum and maximum WRED thresholds. You can configure different weights for WRED and ECN operation to finely tune how different types of traffic are handled when a WRED threshold is exceeded. Benefits of Using a Configurable Weight for WRED with ECN Using a configurable weight for WRED and ECN allows you to specify how the average queue size is calculated. In WRED, the average queue size determines when a threshold is exceeded and packets are dropped; in WRED with ECN, the average queue size determines when packets are marked for later Quality of Service (QoS) 865