QOS On Cisco Integrated Services Routers

Unanswered Question
Dec 29th, 2008

I have two sites connected by Frame-Relay. At Site (A) is a Cisco 2801 with IOS 12.3, and at Site (B) is a Cisco 1841 with IOS 12.4. Each site uses a VoIP solution NOT Cisco. The connection is a full T1.

I need to prioritize this voice traffic over the frame.

In the past, with other routers, i have accomplished this by prioritizing the TCP and UDP Ports the voice traffic opperates on (Much like an access list).

Also, in the past on cisco, i have used the QOS/COS map (this VoIP Uses DSCP 46).

On this situation, the 1841 with IOS 12.4 does not have the mls commands, and on the 2801 with IOS 12.3, it does not have all the mls commands that are in 12.4

Could you recomend a configuration to prioritize the voice traffic over this connection.

Thank you


I have this problem too.
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Collin Clark Mon, 12/29/2008 - 11:26

If your phones tag DSCP and the switches honor them, then you don't need CoS to DSCP mapping. Here is a config example.

<font size="2"></p><p>class-map match-all VOICE</p><p> match ip dscp ef </p><p>class-map match-any CALL-SIGNALING</p><p> match ip dscp cs3 </p><p>      </p><p>policy-map WAN-EDGE</p><p> class VOICE</p><p>  priority percent 33</p><p> class CALL-SIGNALING</p><p>  bandwidth percent 5</p><p> class class-default</p><p>  fair-queue</p><p></font>

Hope that helps.


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