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New Member

QoS configuration

Hi ,

i would like to configure QoS on 3750  switch, so that i can reserve 50% b/w for voice and 50% for data.



New Member

Re: QoS configuration

Hi Neo,

QoS is a rather delicate technology, I would say spitting out some config wouldnt really do you or your network any justice. I suggest you review some of the theory behind implementing QoS. I recommend the Cisco Press Qos certification guide (ISBN 10: 1-58720-124-0).

In essence you will need to do 3 things:

Classify your traffic

Mark your traffic

Police your traffic

The configuration guide for hte 3750's will show you how to configure each of these (

I'd also recommend looking at AutoQoS, given you only want to slipt voice from data this might be your easiest option (it's an automated qos deployment tool/script)



Cisco Employee

Re: QoS configuration

Hi Neo,

First you need to classify the voice and data traffic. You can achieve that by  using ACL to classify based on IP and port number. Then you need to mark each class to a DSCP or COS value. Base on the DSCP or COS value you can configure the queue for each class, and decide wether you want put voice in priority queue or bandwidth reserved queue.

You can read the 3750 qos configuration guide first.


Lei Tian

Re: QoS configuration

Hi Neo

50% seems a little high for VOIP. This leaves less bandwidth for other important applications. I've seen recommendations that you should only set aside 33% for VOIP. See below


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