Subject: [Sip] UPDATE Method & Glare

From: "George Foti (LMC)" <[email-masked]>
Date: Wed, 27 Feb 2002 18:08:50 -0500

Hi,

Within the current draft on UPDATE method, glare can occur within a
dialogue.
I mean it is perfectly okay for 2 UAs to send simultaneous UPDATES causing
glare.

I dont see anywhere where this case is covered in the current draft.
Can that be added to the draft to specify the procedures to be followed
should that situation arise.

Thanks

George Foti
Ericsson Canada

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---

From: "Mark Watson"<[email-masked]>
Date: Thu, 28 Feb 2002 18:29:27 -0000

I agree - this needs to be described.

If I remember some earlier discussions correctly, then if you receive an
UPDATE whilst waiting for a response to an UPDATE that you send yourself,
the you should immediately reject the UPDATE, but with what failure response
I do not know.

Do we require a specific failure response for glare ? I guess you need to
know that it is worth retrying after some random interval.

Also, if you are waiting for a repsonse to an UPDATE you have sent, and you
receive an UPDATE which is a retransmit of one you have previously responded
to (presumably because your original response was lost), I believe you
should just repeat your original response and continue waiting for the
response to your UPDATE.

Your UPDATE will probably be rejected, because the other guy thinks there is
glare, but it is possible for both UPDATES to suceed if messages swap order
in transit, but this is not a problem.

Is this taken care of by the transaction layer in SIP or does it need to be
explicitly described ?

Regards,

Mark 

> -----Original Message-----
> From: George Foti (LMC) [mailto:[email-masked]]
> Sent: 27 February 2002 23:09
> To: [email-masked]
> Subject: [Sip] UPDATE Method & Glare
> 
> 
> Hi,
>