I was wondering if anybody has encountered the following problem:
- we have a CallManager 7.0 Cluster with a recording solution (CallRec from Zoom)
- let's say we have Phone A calling Phone B
- Phone B has a call recording profile configured; the SIP trunk to the CallRec server has a Device Pool asociated with it (therefore a Region with a codec)
- The codec between Phone A and Phone B is negotiated depending on the regions configured
- The streams to the recorder server are sent as soon as Phone B picks up
The PROBLEM is that if the codec negotiated between Phone A and Phone B is different than the codec negotiated between Phone B and the SIP trunk to the recording server, Phone B does not send any audio streams to the recording server.
After continuous testing we found that if the codecs are the same the stream gets sent, otherwise it does not.
After viewing the trace files I saw that CUCM locks the codec negotiated between Phone A and Phone B, and after that it sees that the call between Phone B and the recording server requires a different codec. It tries to allocate transcoding resources but it does not succeed.
I tried allocating the software MTPs as well as hardware ones provided by some DSP modules on local voice gateways.
It did not work.
I found that somebody on the forum posted the same issue but in regard to the Transfer functionality of an IP Phone with call recording configured (the problem was caused by the codec mismatch).