Recommendation for "wrr-queue cos-map" command

Unanswered Question
Jun 24th, 2007

Hi All,

I need some recommendation for command 'wrr-queue cos-map' for voice configuration.

wrr-queue cos-map transmit_queue_# threshold_# cos1 [cos2 [cos3 [cos4 [cos5 [cos6 [cos7 [cos8]]]]]]]

The cos value for VOICE bearer is: 5, VOICE signaling is: 3. Is it necessary to put VOICE bearer and VOICE signaling to the same threshold? What could be the impact if put them in two different threshold?

Thank you for help.

I have this problem too.
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royalblues Sun, 06/24/2007 - 05:21


AS a standard practice, voice bearer traffic is mapped to the strict priority queue.

The signalling traffic is not mapped to the priority queue.

eg..for a 4 queue configurations

CAT2950(config)#wrr-queue cos-map 1 1

CAT2950(config)#wrr-queue cos-map 2 0

CAT2950(config)#wrr-queue cos-map 3 2 3 4 6 7

CAT2950(config)#wrr-queue cos-map 4 5

HTH, rate if it does


trinawong Sun, 06/24/2007 - 06:26

Hi Narayan,

Thanks a lot for your help.

We had a stress test by injecting traffic to test the voice quality. When we put voice bearer to PQ only, voice quality is decreasing quickly, but once we put the voice signaling to the same queue as voice bearer, there is no voice issue. Would like to verify if this the standard configuration by putting singaling with bearer to the same PQ? I checked cisco documentation that not mention it's necessary.

Thank You,

Pavel Bykov Sun, 06/24/2007 - 12:17

Cisco recommends putting signalling traffic apart from bearer traffic.

Priority queue should be used for voice bearer, real-time video, or other real-time very critical applications. Cisco recommend putting signaling in another queue that is not priority, since signaling can sustain higher delay, jitter and loss than bearer traffic. Non the less, it is still sensitive and should not be mixed with greedy applications.

Do you inject traffic that falls in the same queue as signaling? Try putting signaling in different queue than your applications.

Like this:

wrr-queue cos-map 1 0 1 2 4

wrr-queue cos-map 2 3

wrr-queue cos-map 3 6 7

wrr-queue cos-map 4 5


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