[SIPForum-discussion] [Sip-implementors] Offer/Answer question

[Manpreet Singh]

Wasn't denying the use of update on confirmed dialog, just saying the
recommended use of UPDATE is for early dialog and not for confirmed
based on the spec.

""Although UPDATE can be used on confirmed
dialogs, it is RECOMMENDED that a re-INVITE be used instead. This is
because an UPDATE needs to be answered immediately, ruling out the
possibility of user approval. Such approval will frequently be
needed, and is possible with a re-INVITE.""

Thnx

-----Original Message-----
From: Paul Kyzivat [mailto:pkyzivat at cisco.com] 
Sent: Saturday, April 12, 2008 11:49 PM
To: Manpreet Singh
Cc: kaiduan xie; Bob Penfield; discussion at sipforum.org;
sip-implementors at lists.cs.columbia.edu
Subject: Re: [Sip-implementors] Offer/Answer question

It is permitted to use UPDATE after a dialog has been established. AFAIK
the flow shown is legal. In any case from the POV of the UAS, it is no
different than if the ACK had been sent first and then the UPDATE send,
with the UPDATE arriving first, which can happen.

	Paul

Manpreet Singh wrote:
> I believe the recommended use of UPDATE for offer/answer is in early 
> dialog state but after 200OK, its in confirmed dialog state. But if 
> that limitation werent there, then it might just be valid to do it 
> too. May be other folks can confirm?
> 
> M
> 
> -----Original Message-----
> From: kaiduan xie [mailto:kaiduanx at yahoo.ca]
> Sent: Friday, April 11, 2008 10:32 PM
> To: Bob Penfield; Manpreet Singh; discussion at sipforum.org; 
> sip-implementors at lists.cs.columbia.edu
> Subject: Re: [Sip-implementors] Offer/Answer question
> 
> Is the following case legal?
> 
> UAC                              UAS
> INVITE/SDP  ------------------->
> <-------------------------------- 200/SDP, UPDATE/SDP 
> ---------------->
> <------------ 200 for UPDATE/SDP
> ACK(no SDP) ------------------>
> 
> There is no PRACK in the call flow.
> 
> Thanks,
> 
> kaiduan
> ----- Original Message ----
> From: Bob Penfield <BPenfield at acmepacket.com>
> To: Manpreet Singh <msingh at ibasis.net>; "discussion at sipforum.org"
> <discussion at sipforum.org>; "sip-implementors at lists.cs.columbia.edu"
> <sip-implementors at lists.cs.columbia.edu>
> Sent: Friday, April 11, 2008 5:54:36 PM
> Subject: Re: [Sip-implementors] Offer/Answer question
> 
> Yes. The 200 OK (or the 180 if using 100rel) MUST have the answer.
> 
> cheers,
> (-:bob
> 
> -----Original Message-----
> From: sip-implementors-bounces at lists.cs.columbia.edu
> [mailto:sip-implementors-bounces at lists.cs.columbia.edu] On Behalf Of 
> Manpreet Singh
> Sent: Friday, April 11, 2008 1:47 PM
> To: discussion at sipforum.org; sip-implementors at lists.cs.columbia.edu
> Subject: [Sip-implementors] Offer/Answer question
> 
> For an INVITE carrying an offer, does the offer/answer has to complete

> within the INVITE transaction? Can it complete outside the transaction

> but within the same dialog? Call flow is:
> 
> -------------->Invite ( offer )
> <------------180 ( ringing )
> <------------200OK ( empty..no offer )
> ------------->ACK
> <------------Re-Invite ( Answer to offer in first invite )
> -------------->200OK
> <--------------ACK
> 
> M
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