QoS Problem

Unanswered Question
Dec 31st, 2007
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I have configured QoS for a branch router, we are using IP Telephony with voice codec G.729, when i applied the QoS config "as attached" we faced voice quality bad issues and sometimes one end did not listen to the other end at all, and also some data applications delays.

When i removed the service policy from the outbound interface at the remote site everythings works fine. by theway this sample config is applied at remote site with speed 768Kbps "TDM".

I think this is due bad QoS settings & configuration.

Please review it

Cisco Router 2811 with IOS "ADVENTERPRISEK9-M" version 12.4(6)XT

The priority BWD "50" according to 4 voice calls "G.729" with cRTP.

Thanks in advance

Abd Alqader

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Adam Frederick Mon, 12/31/2007 - 07:12
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I think you're trying to get too complex. YOu need to up your bandwidth classes too.

Try this;

class-map match-all VOICE

match ip dscp ef


policy-map VOICE

class VOICE

priority 384


interface serial0

service-policy output VOICE

a.cruea1980 Mon, 12/31/2007 - 08:07
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I agree that you're getting way too complex.

All you need at your remote site is an output policy. For the DSCP values, why don't you have your equipment set to trust the DSCP value provided by the phones?

a.hajhamad Mon, 12/31/2007 - 10:07
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Hi my friends,

Yes, the case is very complex. Anyway, i think matching voice traffic by using the matching rtp audio is ok, right?


Abd Alqader

a.cruea1980 Thu, 01/03/2008 - 07:04
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You CAN match only the RTP audio, but it's not really recommended.

The best thing is to QoS the signaling and the RTP audio to ensure no drops.


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