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User:MoepMan/QoS

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Setting up QoS for Streaming with a Cisco Router

This example has been tested on a Cisco 2621, but the commands used should be supported on several Ciscos.
I assume you already have it setup so that it routes your traffic towards the internet.

Defining the access-list

! replace <STREAM-SERVERS-IP> with the actual IP of the sreaming server
! if there is more then one streaming server you can just copy and pase this line
! and replace <STREAM-SERVERS-IP> with the actual IP of another sreaming server
! this rule matches all traffic from the stream server (to any host)
access-list 151 permit ip <STREAM-SERVERS-IP> 0.0.0.0 any

Defining the class-map

class-map CSTREAM
 match access-group 151

Defining the policy-map

! repalce <MIN-BW> by the actual value in kbit/s you want to reserve for streaming
! this can be higher then needed, no bandwidth will be wasted
policy-map PSTREAM
 class CSTREAM
  priority <MIN-BW>
 class class-default
  fair-queue

Apply the policy-map to an interface

! note that this interface should be facing your LAN
! again: repalce <DOWNSTREAM-BW> with your downstream bandwidth in kbit/s
! note: you should set this a little lower then your actual bandwidth
! you might have to experiment a bit with this value
int fa0/1
 bandwidth <DOWNSTREAM-BW>
 service-policy output PSTREAM

Disclaimer

I am not a Cisco guru and especially not in the complex field of QoS.
So this config might be not the best you can do in terms of QoS.
You might want to consider giving packets going back to the streaming server (ACK) a higher priority as well.

Comments?

Got any improvements? Let me know!
You can reach me in the #28c3 and #no-nerd-left-behind IRC channels of freenode as m4rku5
You can also contact me via Jabber/XMPP: m4rku5 AT jabber DOT ccc DOT de