PIX515 allows G.711 calls but not G.729 calls...

[crac74]

Hi,

I try to make G.729 calls with Nortel Softphone over VPN and it's curious but voice drops after a few seconds while signalisation still good. After 1 minute with no voice the softphone application crashes. If I use G.711 codec I have no problem at all.
All ports to be opened are opened. Ports are the same when using G.711 or G.729 or whatever the codec is.

Softphone <---> VPN concentrator <---> PIX515 <---> IPBX

When using G.711 we have no logs on the PIX515. It's ok all is working fine.
When using G.729 at the time the voice drops we have a few lines of logs like this :
Deny udp src insideip ipbx/5210 dst outsideip softphone/5200 by access-group "acl_outside"

5210 and 5200 are RTP ports.

I don't understand because if using G.711 with the same PIX configuration and access list it doesn't block the call. No such logs.

I have already created another access-list to allow the ports indicated on the logs. Now I don't have any more logs with G.729 calls but voice stills droping after a few seconds...

Any ideas ?

 

[Supergrrover]

What version are you using - there are unresolved caveats with 6.3(4)
CSCef17488 PIX SIP fixup does not map RTP port correctly

What fixups are in place?


Brent
Systems Engineer / Consultant
CCNP, CCSP

 

[crac74]

We use PIX515 6.3(4)
This is a Nortel Softphone so it uses a proprietary signalisation called Unistim. Like the Cisco's signalisation named Skinny.
Ports to be opened are 4100, 5100, 7300 for Unistim signalisation and range 5200-5263 for RTP ports. So we don't use SIP.

Another point : I've just tested the configuration
Softphone <---> PIX515 <---> IPBX

And...it works fine with G.729 !
So it seems to be a VPN problem. Or a VPN + PIX515 association problem.