Confused on congestion avoidance along with congestion management.

kpjungle

Hi,

I am a bit confused on when to use wred along with your queuing mechanism. Study material goes into some depth on what wred does, however, my question is, you normally use both right? congestion management to get your packets to the hardware queue in the fashion you want, and wred to make sure the queues within whatever queuing mechanism you use, dont get tail dropped, so its a combination of both. Is that correct?

I could also see that wred could be applied on a per interface?

EdTheLad

Congestion management is used to determine which queues traffic is placed in and how these queues are prioritized with regards to the scheduler.
Queueing methods are PQ,CQ,WFQ,CBWFQ,LLQ.
Congestion avoidance like wred is used on each individual queue, thesholds are configured and when the thresholds are exceeded traffic is dropped randomly per class of service.
So to answer your question, yes you use both together, but as i remember some queueing methods dont allow wred so you'll have to do some reading on where its supported etc.