[cisco-voip] No Audio on MGCP Hairpin

[Bernhard Albler]

Hi guys,


I currently i have a little issue, someone else might have stunmpled upon:
MGCP Gateway(2811, running 12.4(8a)), controlled by ccm 5.04-2121. Behind the gateway there is a siemens hicom 300 pbx. We are running iso qsig between the two systems.
When using CFA, or a translation pattern inside of ccm, and this results in a hairpinned call (in via the mgcp gateway, and out of the same gateway) which has no audio. SO neither sides hears anything, signalling is just fine.
If I do a consult. Transfer the same way (e.g. I implemented this with an ipcc-x script as a workaround for now), the audio is cut through just fine.

The q931 traces on the gateway show, that both channels seem to be connected just fine, a show call active voice shows, that there are still ip call legs, both pointing at the ip of the gateway.

Anyone run across this? Am I doing something fundamentally wrong?

Regards
bernhard



------------------------------------------
DI (FH) Bernhard Albler
Systems Engineer
 
NTS Netzwerk Telekom Service AG 
Gastgebgasse 27
1230 Wien
 
Tel: +43 (0) 1/867 67 76-0
Fax: +43 (0) 1/867 67 76 -56
 
Web: http://www.nts.at 
email: balbler at nts.at
------------------------------------------
"A doctor can bury his mistakes but an architect can only advise his client to plant vines."
Frank Lloyd Wright