When a call is "transferred" by a service or identity in the Netvanta ECS, I am seeing a "c=IP4 0.0.0.0" in the SDP media which causes one-way speech path from attached communications system.
So far, the only way I have found to work around this issue is to use a 904, covert the call stream to PRI, then take the PRI back to SIP.
The attached communications system says that their unit is performing as designed, since the "c=IP4 0.0.0.0" is "old" method of being on hold. And, the call should not be "on hold" since the call is being transferred by the service, not put on hold.
I am using a 3430 SBC for connection to SIP TRUNKS, and have even tried transferring the call from the ECS back to the 3430 then to the other communications system, however, at this point the "c=IP4 0.0.0.0" is still part of the SDP message.
The PRI solution is working, I just hate to have to do this just to clean up the SDP message. Any help would be GREAT!
Mike, would you be able to provide a packet capture of the call flow? Depending on how the transfer services are set up, that 0.0.0.0 is most likely a placeholder for the call setup until the correct audio path can be established. Thanks