[Asterisk-Users] RTP stream missing the target - cisco 5300 + mgcp

[Ekke Einberg]

Hi!

I have strange problem, I hope it's just a configuration problem, but 
maybe not.

I'm trying to make a call between a MGCP gateway and Cisco 5300 talking SIP.
Everything is fine except that audio is one way (from 5300 to MGCP 
gateway only). It seems that during reinvite Cisco gets confused by 
session ID and version and excpects RTP stream on different port. The 
call flow on SDP level is following (ports and id's are pure fantasy for 
easier reading):

* -> MGCP   CRCX     (session 1, port 3001, destination *)
* -> 5300   INVITE   (session 1, port 3002, destination *)
5300 -> *   OK       (session 2, port 4001, destination 5300)
(ring and answer, * tries to bridge the call legs)
* -> MGCP   MDCX     (session 1, port 4001, destination 5300)
* -> 5300   INVITE   (session 1, port 3001, destination MGCP)
5300 -> *   OK       (session 3, port 5001, destination 5300)

at this point cisco expects RTP stream to port 5001 but it goes to 4001 
and gets lost. Stream from 5300 to MGCP box goes OK to port 3001. Also, 
on second invite 5300 complains about session ID mismatch. Asterisk uses 
same session id all the time, but in reply from 5300 the session id and 
version are different.

using 'canreinvite=no' helps for calls going to 5300, but then the 
streams are bridged at asterisk server - unacceptable + calls FROM 5300
still have that problem.
OTOH someone surely have similar setup working - help pls.

regards,
ekke