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VOIP QOS problems

I've been trying to configure some QOS functions on my 877W. I've followed a number of examples and used the following (trimmed) configuration:

class-map match-any VOIP-Data match dscp ef class-map match-any VOIP-Signalling match dscp cs3

policy-map QOS-VOIP class VOIP-Signalling bandwidth 8 class VOIP-Data bandwidth 96 class class-default fair-queue

Interface Dialer0 service-policy output QOS-VOIP

When I do 'show policy-map inter dial 0', I see the following:

Dialer0

Service-policy output: QOS-VOIP

Class-map: VOIP-Signalling (match-any) 0 packets, 0 bytes 5 minute offered rate 0 bps, drop rate 0 bps Match: dscp cs3 (24) 0 packets, 0 bytes 5 minute rate 0 bps Queueing Output Queue: Conversation 73 Bandwidth 8 (kbps)Max Threshold 64 (packets) (pkts matched/bytes matched) 0/0 (depth/total drops/no-buffer drops) 0/0/0

Class-map: VOIP-Data (match-any) 0 packets, 0 bytes 5 minute offered rate 0 bps, drop rate 0 bps Match: dscp ef (46) 0 packets, 0 bytes 5 minute rate 0 bps Queueing Output Queue: Conversation 74 Bandwidth 96 (kbps)Max Threshold 64 (packets) (pkts matched/bytes matched) 0/0 (depth/total drops/no-buffer drops) 0/0/0

Class-map: class-default (match-any) 0 packets, 0 bytes 5 minute offered rate 0 bps, drop rate 0 bps Match: any Queueing Flow Based Fair Queueing Maximum Number of Hashed Queues 64 (total queued/total drops/no-buffer drops) 0/0/0

It's clearly not matching packets, VoIP or otherwise. It's probably a really stupid mistake, but I'd appreciate any ideas!

Cheers, Chris

p.s. I've doe a sniff on the VoIP PBX and can see it sending packets with the DSCP field set to EF (0xB8)

Reply to
Can2002
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Hi Chris,

You may wish to investigate the Cisco Router Configure QoS Template:

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Sincerely,

Brad Reese

2007 Cisco Salary Rates
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Reply to
www.BradReese.Com

Hi Brad,

Thanks for that.

I got to the bottom of the problem after a bit more checking; I'd left a route-map entry on my internal interface that was stopping the service-policy on the dialer interface. Once I removed it I immediatly started getting matches. I can now properly experiment with QOS, so I'll definitely take a look at the template!

Cheers, Chris

Reply to
Can2002

OK, the policy-map is now picking up the traffic, but it's not doing much good if I kick off a large upstream file transfer.

I'm using an ADSL 2048/256 service and I suspect I'm experiencing serialization delay. I'm wondering whether it's possible to use the policy map to drop packets over a certain size when a VoIP call is in progress. I can match packet size in a class-map, I'm just not sure how to link that into the policy-map (e.g. I don't want to block every large packet, just when a VoIP call is happening).

Cheers, Chris

Reply to
Can2002

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