Subject: [SIP] Killing hung media streams

From: [email-masked]
Date: Fri, 8 Jun 2001 09:28:34 -0600

I have looked through the archives and could not find anything on this
topic, please excuse me if it has been discussed.  We have encountered a
couple of different UAs that are a MGC controlling MGs, and if the UA
crashes and comes back up, a media stream from the MG continues.  By the
time it comes back up, the UA on the other end has done all it's retransmits
trying to tear down the session, and has flushed the call.

 This hung media stream causes problems and consumes resources.  Obviously
some work needs to be done on the MGC - MG implementation to avoid this
problem and clean up after a crash.  However, has there been any discussion
regarding what the receiver of this media might do to inform the UA on the
other end to shut it down (once that UA has come back up)?  I suppose the
receiving UA would need to maintain a history of previous sessions to tie a
media stream back to a UA.  Thoughts?

John Hearty
Level 3 Communications, Inc.

_______________________________________________
This list is for continuing development of the SIP protocol.
The sip-implementor's list is the place to discuss implementation,
and to receive advice on understanding existing sip.
To subscribe to it, send mail to 
[email-masked] with "subscribe" in the body.

---

From: Michael Thomas <[email-masked]>
Date: Sat, 9 Jun 2001 06:49:29 -0700 (PDT)

> media stream back to a UA.  Thoughts?

   It ought to send an ICMP port unavailable. Also: it would
   probably be a good overall thing to use RTCP for liveliness
   heuristics since it's possible that the partition affected
   the MGC as well, in which case you might not be able to
   get the tear down command even with a well implemented MGC.

	   Mike