[cisco-voip] One-way audio after BLIND transfer to SIP Trunk

Wed Apr 30 04:26:21 EDT 2014

Hi Dana,

Have you tried to take packet captures from the back of the phone and see if the stream is reaching the phone from the remote-end?
If there is no MTP/Xcoder invoked, you will see the RTP stream coming directly from the CUBE (assuming that cube is in flow-through mode).

If the SIP traces look fine and IP and ports are exchanged correctly, it's usually something in the network that's not letting the RTP stream pass between the phone and the other end.

Thanks
Sreekanth

From: cisco-voip [mailto:cisco-voip-bounces at puck.nether.net] On Behalf Of Dana Tong
Sent: Wednesday, April 30, 2014 1:45 PM
To: cisco-voip at puck.nether.net (cisco-voip at puck.nether.net)
Subject: [cisco-voip] One-way audio after BLIND transfer to SIP Trunk

Good evening all,

A colleague and myself have discovered an issue where a Blind transfer has one-way audio.

The scenario is as follows:
IP Phone to IP phone call
Transfer to off-net mobile via SIP Trunk (via CUBE)
Blind Transfer

When the remote person answers the phone, there is audio heard on the remote party, but nothing on the IP phone.

The SIP trace SDP appears OK. The IP addresses seem to be c=IN IP is correct.
The web page for the phone reports Stream = Not Ready.

Does anyone have any tips or thoughts on this issue? Have tried a number of config changes with respect to supplementary services on the CUBE, and MTP etc on the CUCM Trunk.

Cheers
Dana

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