qos on my switches

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Jul 24th, 2009
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Hi all

when talking about qos, if I trust frames at layer 2 cos say for voice, how do i know which queues they go into? would this put them into both an egress and ingress queue ? and how do i know what kind of queue it is, can i change what queue they go into also ?

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Peter Paluch Fri, 07/24/2009 - 06:45
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QoS handling on switches depends very much on their type, as each Catalyst series does it in a different way. But basically, the COS marking is used for sorting frames into egress queues, and you can decide which COS values map to which queues.

What type of switch are you interested about?

Best regards,


carl_townshend Fri, 07/24/2009 - 08:30
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we are talking about c2960 , these will then plug into cat 6509's


Peter Paluch Fri, 07/24/2009 - 11:37
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Regarding the QoS processing on Catalyst 2960 series, please visit this page:


Here, select your IOS version and then look for topic "Configuring QoS" in the table of contents on the left side. This chapter contains a thorough description of the individual queueing mechanisms and QoS tools available on Catalyst 2960 series. It might not be an easiest reading but it is by far the best source of information for you.

Regarding the 6509 switch, their QoS mechanisms are more complicated because of the more complex architecture of the 6500 series. Check out this page:


Again, here, select your IOS version and look for "QoS" or "Quality of Service" links in the table of contents.

I hope this helps a bit.

Best regards,



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