Reference Guide

6. Enable WRED/ECN on a port.
OS10(config)# interface ethernet 1/1/1
OS10(conf-if-eth1/1/1)# random-detect wred_prof_1
7. Enable WRED/ECN on a service-pool.
OS10(config)# system qos
OS10(config-sys-qos)# random-detect pool 0 wred_prof_1
Configure congestion avoidance for the S4200
NOTE: For the S4200 platform, ECN can be enabled globally only. Also, ECN configurations can be applied only at the
queue level. You cannot configure ECN at interface and service pool levels. In the S4200, if you try to apply the ECN
configure at interface or service pool levels, the configuration is not accepted.
1. Configure WRED profile in the CONFIGURATION mode.
OS10(config)# wred wred_prof_1
2. Configure WRED threshold parameters for different colors in the WRED CONFIGURATION mode.
OS10(config-wred)# random-detect color yellow minimum-threshold 100 maximum-threshold
300 drop-probability 40
3. Configure the exponential weight value for the WRED profile in the WRED CONFIGURATION mode.
OS10(config-wred)# random-detect weight 4
4. Configure the ECN threshold parameters in the WRED CONFIGURATION mode.
OS10(config-wred)#random-detect ecn minimum-threshold 100 maximum-threshold 300 drop-
probability 40
5. Exit the WRED CONFIGURATION mode.
OS10(config-wred)#exit
6. Enter QOS POLICY-MAP mode and create a queuing policy type.
OS10(config)#policy-map type queuing pol-map-1
7. Create a QoS class for the queuing policy type.
OS10(config-pmap-queuing)#class default
8. Assign a WRED profile to the specified queue.
OS10(config-pmap-c-que)#random-detect prof1
9. Exit class map and policy map modes.
OS10(config-pmap-c-que)#exit
OS10(config-pmap-queuing)#exit
10. Enter the SYSTEM QOS mode.
OS10(config)#configure system-qos
11. Enable ECN globally.
OS10(config-sys-qos)#random-detect ecn
After you enable ECN globally, ECN marks the CE bit of ECN field in a packet as ECT.
In the S4200, you can configure separate thresholds for ECT. If ECN is enabled, ECN capable traffic (ECT) is marked based on
the configured ECN threshold and non-ECT is dropped based on the WRED thresholds.
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Quality of service