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Cross talk on Voip

Hi all

We are using an AS5350XM as a GTW and all voice traffic on a VPN.

we get a fair bit of X-tall...since I am no voice expert but kno what that I should not be getting this issue with VoIP.

Any thoughts ?

TIA

Sam

8 REPLIES
Blue

Re: Cross talk on Voip

Sam,

Are there any analog legs to the calls? Maybe POTS lines to a small business? You are correct that VOIP or other digital formats are not prone to cross talk.

Dave

Re: Cross talk on Voip

Hi there

yes there is an analog leg to a local telephony provider (3 E1 are used).

where should I start looking, at present I am looking at debug MGCP errors. trying to find a pattern on where call X-talk on on which channel they are carried.

TIA

Sam

Blue

Re: Cross talk on Voip

Sam,

E1s are TDM and digital so that is not likely to be where the crosstalk is occurring. Where are the endpoints? Any analog service involved?

Can you place test calls that exhibit crosstalk?

If you can pin it down to calls on a specific E1, you could try swapping ports to see if the problem follows the circuit or the port. A faulty DSP could cause crosstalk (though I have never seen it).

Dave

Re: Cross talk on Voip

Hi Dave

only the 1st 4 E1 are in use.

I agree that I need to correlate a call with X-talk to a particular channel...how is my problem.

Sam

sh mgcp endpoint

E1 S3/0 ds0-group 1 timeslots 1-15,17-31 type none

E1 S3/1 ds0-group 0 timeslots 1-31 type none

E1 S3/2 ds0-group 1 timeslots 1-15,17-31 type none

E1 S3/3 ds0-group 0 timeslots 1-31 type none

E1 S3/4 ds0-group 0 timeslots 1-31 type none

E1 S3/5 ds0-group 0 timeslots 1-31 type none

E1 S3/6 ds0-group 0 timeslots 1-31 type none

sh voice dsp, does not show much.

DSP DSP DSPWARE CURR BOOT PAK TX/RX

TYPE NUM CH CODEC VERSION STATE STATE RST AI VOICEPORT TS ABORT PACK COUNT

==== === == ======== ======= ===== ======= === == ========= == ===== ============

Blue

Re: Cross talk on Voip

Sam,

Try debug isdn q931.

That will show you calling/called number and E1 channel used.

Please rate helpful posts.

New Member

Re: Cross talk on Voip

Is the problem fixed?

E1s can't have cross talk, but if they are wrongly patched, they do cause cross talk, like swapping, TX and RX.

Please verify the patching of E1s.

Re: Cross talk on Voip

Hi

problem is still there, I will do some debugging as suggested by Dave.

all what I need is to correlate a bad E1 to a corrupted call. then the fault is isolated and can be dealt with.

I will feedback either way when I am done with debug.

Many thanks for the replies !

Sam

Re: Cross talk on Voip

debug isdn is not suported, I am using

debug mgcp XX instead..with thsi casn see teh endpoint when calls are made.

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