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New Member

Capturing Call Statistics for Analyzing one-way audio problem

I am experiencing an intermittent one-way audio problem.  Perhaps one in a couple hundred calls.  I've told the user to hit the "?" on his 7945G phone to glean what's going on during the call in terms of codec, packets received, loss, jitter etc.  Is there a way I could get this information on the back end somehow?  I don't see any of that in Call Detail Records.  I've attached a screen cap of the data I am looking to obtain without having to bother the users to remember to hit the "??" and write all that mumbo down.

on a related note I am working the some of the suggestions in this Cisco doc..

http://www.cisco.com/en/US/tech/tk652/tk698/technologies_tech_note09186a008009484b.shtml#verifymtp

6 REPLIES
Cisco Employee

Re: Capturing Call Statistics for Analyzing one-way audio proble

You may want to look at implemeting QRT. Pl. see:

https://supportforums.cisco.com/docs/DOC-5308

If the RTP is between an IP phone and a TDM GW, you

can also do a trigerred PCM capture. This  requires

little config and TCL installation  so opening a SR with

TAC will be recommended. But its an extremely useful

tool for such intermittent issue and its very easy to use.

All ip phone user needs to do is hit *** while on a problem

call to kick in a dsp dump which will provide use with

rtp streams entering and leaving the dsp.

New Member

Re: Capturing Call Statistics for Analyzing one-way audio proble

Thanks for the info on QRT.  I will have another go on that based on your info.  Out of the box - QRT did not seem to function.

It would for example throw all call legs into a single quality bucket "N/A".

Re: Capturing Call Statistics for Analyzing one-way audio proble

If it's happening to only one user, you also may want to set up a sniffer trace and leave it on until the next occurrence.  Then just have the user take note of what time the one-time audio occurred and have a look at the trace for more details.

New Member

Re: Capturing Call Statistics for Analyzing one-way audio proble

I did think of this - enabling the port spanning on the phone and letting wireshark have at it.

But it seemed to pack on the megabytes very quickly in my test run.  But may just need to

do this.  Or perhaps I could put it in a circular self-overwrite mode.

Re: Capturing Call Statistics for Analyzing one-way audio proble

Also here's a great video of troubleshooting VOIP issues with Wireshark:

https://supportforums.cisco.com/videos/1286

Cisco Employee

Re: Capturing Call Statistics for Analyzing one-way audio proble

If you open a TAC SR, you can request that they give you information on how to run the triggered PCM capture script.

When a user has an issue, they can hit '***' and it will get an audio recording off the PSTN's DSP along with call statistics from the gateway for the call with the issue, and save it all to a TFTP server.  Run 15.x with it, and you can also get a packet capture just for that call on the router's LAN egress towards the IP phone.  Pair that data with a QRT report for the same call, and you have stats from both ends, and a capture of the audio payload for the GW->IP phone direction.

That would be enough information to identify if it is a provider, network, or phone issue.

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