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Wireshark-users: Re: [Wireshark-users] Analyzing RTP Streams

From: Jaap Keuter <jaap.keuter@xxxxxxxxx>
Date: Thu, 09 Sep 2010 08:05:45 +0200
Hi,

A payload change to payload type 0, could mean one of three things:
An invalid payload, ZRTP, STUN or T.38. You can configure the RTP dissector for that interpretation. Where these packets come from is a little hard to determine from this. I assume you capture at the inside, so there's a gateway at the outside which may manipulated/transcode the speech. Errant T.38 detection is not unlikely.

Thanks,
Jaap


On 09/09/2010 02:06 AM, Dustin Schuemann wrote:
I am trying to diagnose a VOIP issue. When I play the call it sounds
fine. The call doesn't have any dropped packets. It does say payload
changed to PT=0. The mean jitter was 1.29 ms, Max jitter was 12.64 ms.
and the max delta was 22.93 ms. The internal caller hears the end users
voice drop every other word. The outside caller doesn't have any issues.
I believe this is a network issue but Im not able to pin point it. I
guess I don't quite know how to read the RTP analysis screen.

Any help you can provide would be grateful.