No subject

issued to Asterisk with an inactive SDP attribute. Asterisk replies with
inactive SDP and re-INVITES the SIP PSTN channel so the RTP is now going
through Asterisk, music on hold is played to the PSTN channel.

Cisco then re-INVITES with no SPD, Asterisk responds with sendrecv and
Cisco acknowledges with  sendonly SDP attribute, after this Cisco sends
music on hold directly to the SIP PSTN channel. Asterisk repeats the
previous re-INVITE on the PSTN channel and sends music on hold. The result
is that the held party receives two RTP streams, one from Cisco UCM and one
from Asterisk, each playing music on hold.

It is believed that Cisco issues inactive between placing the call on hold
and generating music on hold. This also appears to be performed when the
call is taken off hold. 

It is believed that when Asterisk receives the sendonly it should stop
sending RTP to the held channel. 

======================================================================
Relationships       ID      Summary
----------------------------------------------------------------------
related to          0016313 Responds sendrecv to recvonly SDP, but ...
====================================================================== 

---------------------------------------------------------------------- 
 (0114992) davidw (reporter) - 2009-12-09 11:41
 https://issues.asterisk.org/view.php?id=16373#c114992 
---------------------------------------------------------------------- 
As a short term solution, we may resort to pointing music on hold at an
empty directory, which results in Asterisk not sending any RTP.  In its
simplest form, this completely destroys the music on hold capability, of
course.  The other risk, in the simple form, is that anything with
something like Asterisk's rtptimeout, and without the double MOH problem,
might think the connection had failed. 

Issue History 
Date Modified    Username       Field                    Change               
====================================================================== 
2009-12-09 11:41 davidw         Note Added: 0114992                          
======================================================================