Chunky voice when calling external numbers

Unanswered Question
Apr 2nd, 2010
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Hi, all,


I have a very strange voice  quality problem. We have a remote worker who has 7941 phone plugged to a  C851W SOHO router, C851W is configured as ezvpn client, the 7941 phone  registers to CUCM in HQ, HQ has a 2821 MGCP gateway conncts to PSTN  provider. When this employee makes calls to internal extensions, the  voice quality was perfect, but when he calls external numbers (or  external number calls in), the voice quality was bad. We don't have a  whole lot of internal extentions, so all IP phones in HQ and the MGCP  gateway are in the same subnet. IP connectivity wise, there is no  difference between the audio stream of this remote 7941 <--> HQ  hard IP phones and the audio stream of  this remote 7941 <--->HQ  MGCP gateway. We know the problem is not on PSTN side or MGCP gateway,  because we don't have voice quality problem when making/receiving  external calls from HQ hard IP phones. I can not think where to start  the troubleshooting that makes sense.


Thanks,
Jian

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Aaron Harrison Fri, 04/02/2010 - 10:12
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Hi


I would start by hitting ? twice quickly on the handset when making an external call; this will show you stats that will identify whether you are seeing any packet loss.


It would also be worth doing that on a normal internal call; to compare the stats, and also to see which codec is in effect for each type of call.


If you are switching to a different codec when running the call to the gateway this might explain the difference in quality.


Aaron

jiangu Fri, 04/02/2010 - 15:21
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Hi, Aaron,


Thank you for your time, receiver pack lost was 2, average jitter range from 0-3, latency was 0, codec for both sender and receiver is g.711u.


Jian

Aaron Harrison Sat, 04/03/2010 - 01:45
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Hi


In which scenario?


Remote--> internal

Remote--> external


?


Post both, for comparison.


Aaron

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