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Catalyst Queueing Principles

I'm experimenting with QoS on a Cat6500 with Sup2.

As a general policy, I want to trust my endpoints, so I set all ports to trust-cos and port-based QoS.

Also as a matter of policy, I want only CoS 5 to go into the priority TX and RX queues where available, otherwise into the highest threshold where there is no priority queue (I have both WS-X6548-GE-TX and WS-X6348-RJ45 modules). But depending on the queuing model available, I may wish to put CoS 6-7 into a higher threshold than CoS 0-4.

My question is this: if I want to treat CoS 0-4 (and sometimes 6-7) with equal priority, is it best to put all these values into the next-to-highest threshold, and reserve the highest queue/threshold for CoS 5, or should I spread the lower CoS values across the different thresholds?

Does this make sense? I'm just starting at looking at this kind of configuration.

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Re: Catalyst Queueing Principles

You should always protect COS 6-7 over 0-4 traffic as that is used by routers for routing protocols etc., and nobody is happy when the routers lose their peer relationships.

A good starting point (and often ending point) is to let autoqos set up your queues and thresholds.

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