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QOS for Media traffic


One of our office purchased couple of security IP cams. I configured a 3550 switch and separated the video traffic by creating VLANS. I also applied QOS in a basic level. Now, there is chance of increasing the number of IP cams. So, can any one please help in reviewing the QOS policy that i have used for streaming traffic and suggest me the ways of improving the QOS.

My configs are

mls qos

For IP phones


interface range fastethernet 0/1-4

switchport mode access

switchport access vlan 2

mls qos trust cos

For Video Traffic


interface range fastethernet 0/5 - 6

switchport mode access

switchport access vlan 3

mls qos cos 3

mls qos trust cos

For Rest of Data traffic


interface range fastethernet 0/7 - 23

switchport mode access

switchport access vlan 4

mls qos cos 0

mls qos cos override

interface fastethernet 0/24

switchport mode encapsulation dot1q

switchport mode trunk




Re: QOS for Media traffic

Hi Rajesh,

Are you confident that that video traffic is marked with a Cos of 3 ?

One other thing.. it's not enough to just trust the cos setting for your video traffic, you also need to configure the schedulers on your outbound queues to give this traffic priority over the data traffic. I can't see that you have done that. I suggest you do so to get any benefit out of this...

Pls do remember to rate posts...


New Member

Re: QOS for Media traffic


This is the first time I am applying QOS on a switch.

I went through lot of documents and really lost without knowing what to and how to apply QOS. Atlast I found a doco with the above set of configs. Since it was simple I applied and tested.

As you asked, I am not really sure whether media traffic is using QOS or not. At the moment we use only one cam for testing. Since we don’t have overload the streaming seems to be fine. I guess, when we increase the no of cams I will be knowing the real effect of QOS.

The thing is I have came across lot of documents. But, I don’t know what all needed to be added in the configs for setting up a proper QOS. If you have any sample piece of configs on qos please let me know.

Many thanks for your help and suggestion.



Re: QOS for Media traffic


I would have a look at the following section in the Config Guide to get an understanding of how to configure the queues:

Pls do remember to rate posts.


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