How do I test QoS to confirm it is working correctly?

[Anonymous]

What is the best method to test layer 2 QoS within an Adtran switch?  I need to confirm that voice is being prioritized.  I have captured packets and confirmed that the voice packets (frames) are being marked by the phone as cos 6.  But how do I verify that the expedited queing is operating correctly?

Thanks,

Dan

[Anonymous · Accepted solution]

Dan,

Thank you for your question. Unfortunately, there is not much to look at, in terms of statistics, for class of service. A packet capture is the best way to verify that CoS is functioning as configured.

In most networks, congestion usually does not occur at a layer 2 (switch) level, but at a layer 3 level (usually out the WAN interface). The switch backplane will not be in a congested state for CoS to take affect unless there is enough traffic to take up wirespeed's worth of bandwidth. It would be more essential to have QoS setup at your layer 3 device.

The following document provides more information on Class of Service in AOS:

Configuring Class of Service - https://supportforums.adtran.com/docs/DOC-1628

Let us know if you have any further questions.

Thanks,

Noor

[Anonymous]

Noor,

Thank you.  This was very helpful.

Dan

[Anonymous]

Dan,

I marked this as "assumed answered," but if you have further questions on this topic do not hesitate to reply.  I will be happy to help.

Thanks,

Noor