Subject: RE: [Sip] new I-D on recovery of UA failures

From: "Buller, Jeremy" <[email-masked]>
Date: Tue, 17 Jul 2001 01:20:13 -0400

Hi Vijay,

> Quick question: in Section 4, when UA3 cannot reconstitute a call (after
> UA2, the original UA, has failed), why does UA1 send a BYE?  Does
> sending a BYE help at all?  If UA3 could not reconstitute the call, it >
will probably not be able to process the BYE as well.
My understanding was that UA3 would have received the INVITE, 
determined that it could not reconstitute the call (using the 
description in section 6) and then responded with a 481. Btw,
I liked the ideas for the 'To' tag enhancement algorithm. A
BYE is then 'required' to be sent from UA1 and UA3 should be 
capable of handling this, thus terminating the interaction 
between UA1 and UA3 in the 'standard' way.

Best regards,

Jim Buller

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---

From: Vijay Gurbani <[email-masked]>
Date: Tue, 17 Jul 2001 09:03:54 -0500

"Buller, Jeremy" wrote:
> > sending a BYE help at all?  If UA3 could not reconstitute the call, 
> it will probably not be able to process the BYE as well.

Hi Jim:

I still don't think UA3 will honor the BYE if it send a 481.  As far as it
is concerned, it could not establish a (reconstituted) session, hence it
send the 481.  So why should it honor a BYE?  According to the spec, a
session (barring early media) is established by the UAS sending a 200 OK,
not a 481.

Regards,

- vijay
-- 
Vijay K. Gurbani  vkg@{lucent.com,research.bell-labs.com,acm.org}
Internet Software and eServices Group 
Lucent Technologies/Bell Labs Innovations 263 Shuman Blvd., Rm 1A-413
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