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marcelocbf

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Qos Cisco Voice - Help

Hi Experts ...
I need your help again ...

I have a network connected to the Internet through a Cisco 1721 attached to a 1024 Kbps link from my provider. This network is a little congested now and the most important thing is voice so I need strict priority on this. So ... My current config is ...

LAN port -> FastEthernet0 ------------ WAN port -> Serial0

As the packets enter the router I mark them as VOICE dscp 46 and OTHER TRAFFIC as best-effort (dscp 0), I do this through access-lists coming and going to my PBX box.
At the Internet Edge, I configured LLQ for the packets going out giving the strict priority to the VOICE traffic. And for the packets coming from the Intenet, I rate-limited them and marked with precedence 5 ...

Everything was going ok ... but now I'm experiencing some dead spots on voice ... The latency from my network to my providers is not so low, so I can't add more latency inside the network ...

I checked both the policy maps and rate-limits regarding the Voice traffic and I haven't any packet exceeded ... So I can just think about the MTU that I left default (1500) because as I tried to change in the beginning I had some issues with other applications, including SIP traffic leaving the network ...

I'd like to implement LFI, but I don't know if I can implement in my Serial interface ... Is that possible ? Is there any way to make the packets smaller so they do not add more latency on the edge of the network ? Is there anything that I'm missing with this configuration ?

Thanks,
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mikebernhardt
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marcelocbf

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Yeah ... Unfortunately we cannot control everything ... hehe
But I think that if I fragment the packets and interchange (LFI) them with some priority is gonna help, but I don't know if I can do this on my Serial Interface ...

But do you think is there any other way to do that ? Because changing the MTU is a headache for me ... and I know it would just solve the outbound audio ...

Thanks anyway,