Sounds like a delayed media.
These are various examples of calls published on "Innovaphone" wiki.
Note: 180 Ringing does not contain an SDP-Answer!
Note: 180 Ringing contains an SDP-Answer!
need to confirm if it is delayed because I have a problem of interworking , I have a 2821 ip-ip h323 to Sip and does not work randomly, some calls are going well and others give me cause release 127.
according to the specification, FastStart to delayed media is not supported. If I confirm that the signaling presented in the first sheet is delayed confirming the problem would be.
Early Media and generally progress messages use a 183 response. In your sip session there aren't these type messages, so it is a delayed media.
See draft-rosenberg-sip-early-media-00.txt and draft-donovan-mmusic-183-00.txt