Subject: RE: [Sip] UPDATE and Expires

From: "Sriram Parameswar"<[email-masked]>
Date: Fri, 10 May 2002 09:59:38 -0500

What if you do not control the UAC - and he does not put an Expires header
into the INVITE. Would your UAS then continue to ring for ever? I think the
implementation of the UA's will have to perform some sanity timing that is
not part of the spec (i.e. Implementation specific).

Brian - your point is still valid.

Thanks,

Sriram

__________________________________________
Sriram Parameswar              Phone: 972-685-8540
Interactive Multimedia Server (IMS) Fax: 972-684-3986
Nortel Networks, Richardson USA  Email: [email-masked]

-----Original Message-----
From: Rosen, Brian [mailto:[email-masked]]
Sent: Friday, May 10, 2002 7:26 AM
To: [email-masked]'
Subject: [Sip] UPDATE and Expires

This morning, I arrived to find an experimental SIP implementation 
was "ringing" all night.  It's experimental.  The UAC that called
me died in the middle of the transaction.  Still, my end should
have given up the call at some point.  I go looking for the
codesmith.

The programmer says "That's correct behavior.  Just because the 
caller died, the UAS got an INVITE, and is waiting for the user to 
answer before it sends the 200 OK.  Since this is user time, 
there is no good time after which it is okay to abandon the call"

I protest "But the UAC died!"

And the programmer says "The UAS doesn't know that, as far as it knows,
the user at the UAS wants it to keep ringing"

And I reach for my copy of bis-09 and say "Ah Ha, why don't we put
an Expire header on the Invite, and send 487 if it expires.  And
CANCEL to boot?"

And he says "Sure, but what if the user at the UAC WANTS to wait
longer than whatever the Expires says"

And I reach for my copy of update-02, ready to say "Send an UPDATE
and extend the Expire", but, alas, Expire is not legal on
Update.

And so I wrote this email

Brian

_______________________________________________
Sip mailing list  https://www1.ietf.org/mailman/listinfo/sip
This list is for NEW development of the core SIP Protocol
Use [email-masked] for questions on current sip
Use [email-masked] for new developments on the application of sip