Call Manager H.323 interop issue with non-standard timeout on H.245

[gmdl]

Hi,

We observed the following protocol issue when calling from a Skinny Phone at the Call Manager to a H.323 Gateway:

The call-manager initiates a call without faststart and H.245 tunneling to the gateway. The gateway provides a H.245 transport address within the alert message. The call-manager establishes the TCP connection for H.245. If the gateway does not send a TCS message within 4s the callmanager disconnects the call, without sending a TCS message itself.

There is no such timer defined in H.323, so that seems to be a non-compliance in the callmanager.

Is this a known issue?

Regards

Guntram

PS

Of course we could solve the problem on the gateway side but it should be fixed on the Call Manager

[thomas.chen]

On your h323 gateway you can configure the codecs that it can speak with the voice class codec command under the dialpeer. Configuring this tells the gateway what types of codecs to accept.

[paul.harrison]

Guntram,

According to

http://www.packetizer.com/in/q98.html

This may be fine. The TCS should be the first message transmitted. So call manager sends an Alert, the gateway does not reply with it's TCS so call manager abandons the call.

Which seems perfectly fine to me, Call Manager is attempting to find out if the Gateway exists, gets no reply so gives up.

Paul