(Optional) Configuring an FQ WRED Object

Do as follows on the router:

• If no flow-WRED object is set, the system adopts the default tail-drop policy.
• The upper and lower thresholds for red packets can be set to the minimum; those for yellow packets can be larger; those for green packets can be set to the maximum.
• In the actual configuration, the lower threshold is recommended to begin with 50% and be adjusted based on different colors of packets. 100% is recommended for the drop probability.

By configuring a flow-WRED object, you can set upper and lower thresholds (in percentages) and drop probability for queues. Suppose that the percentage of the actual length of a queue to the length of an FQ is n, the lower threshold is x (in percentage), and the upper threshold is y (in percentage), packets are processed based on the following rules:

• If n is smaller than x, packets are not dropped.
• If n is greater than x and less than y, packets are dropped according to the WRED mechanism. The longer the queue length, the higher the drop probability.
• If n is larger than y, all the subsequent packets are dropped.

You can create multiple flow-WRED objects for FQs to reference as required.