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Community Member

router drops voice packets

Cisco Call Manager at central site and IP 7960 phones at remote site. WAN between them is a 256K link with frame relay encapsulation. QoS is applied to the serial intefaces.

During normal operation voice quality is fine and no packets are lost (RxLost) when looking on the IP phone display (by pressing i button twice).

However when customer does a "show run" etc on the central router speech is broken and RxLost counter incrementings by a few.

When looking at the policy and the interfaces and the queues no packets are being discarded.

Router code is 12.2(13)T1

Anyone seen anything like this?

Community Member

Re: router drops voice packets

i have the same Pb in 3660 GATEWAY with 12.2.11T6 IOS VERSION . before i used a 3640 VOIP GATWAY with 12.2.1 IOS VERSION , all things work very well without errors ( RxLost ).

i had changed the IOS version of 3660 to 12.2.1 BUT the Pb always exists.

i don't know if you have the same voip gatEway 3660 OR NOT ?

Cisco Employee

Re: router drops voice packets


what is the platform and how much memory is on it ?

Community Member

Re: router drops voice packets

i'm using a 3660 voip gateway with 128M of memory. the 3640 voip gateway is with a 96M of memory.

Community Member

Re: router drops voice packets

Oi ! You hijacked my post!

I found out that our customer was experiencing increased jitter, not packet loss. It was because the voice packets were being passed through a route-map and so I suspect being process switched which was being delayed by the show command. It was fixed by using process-max-time 20, which stops a process from hogging the CPU for more than 20ms.

Don't know if this help your,



Community Member

Re: router drops voice packets

can you post your configuration so we can see what exactly you are doing?

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