Subject: AW: [Sipping] Immediate NOTIFIES change in sip-events-01

From: Brazier Lachlan <[email-masked]>
Date: Fri, 9 Nov 2001 12:35:25 +0100

Hi,

> 
> In the diminutive case where the first NOTIFY contains actual Event
> information, the use of a separate ACK just increases the 
> number of messages
> required. Also regardless of whether proxy should or should 
> not treat ACK as
> a separate transaction, I'll bet this will cause many 
> problems existing
> proxies.
> 
I would say, NOTIFY's from several clients to the subscriber including the
responses is a higher network load as one forked ACK.

> I think the immediate NOTIFY mechanism seems to work well within the
> existing SUB/NOT framework for all our reliability 
> requirements (with the
> addition on a Subscription-Status header).

My problem was not the mechanism itself, but the handling of several
NOTIFY's at the SUBSCRIBER.

Lachlan

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---

From: "James Undery" <[email-masked]>
Date: Fri, 9 Nov 2001 12:01:33 -0000

> -----Original Message-----
> From: [email-masked]
> [mailto:[email-masked]]On Behalf Of
> Brazier Lachlan
> Hi,

> responses is a higher network load as one forked ACK.

The idea of adding an ACK is so broken I can't even believe it's being
discussed. ACK isn't even a real request it is used to quench the
retranmission of 200 responses to INVITEs. (INVITEs which are handled in a
totally different manner to all other requests.) Using ACKs for SUBSCRIBE
would require giving SUBSCRIBE all INVITE's behaviour this is not backwardly
compatible and would require the bis being changed to include SUBSCRIBE or
break handling of unknown requests.

> NOTIFY's at the SUBSCRIBER.

Your problem is probably the fact that my presence may be described by an
amalgamation of several PAs i.e. my mobile, my office phone and a PA on
whatever computer I am currently logged onto. If you limit yourself to the
presence of my mobile your concerns will go away, however, you're cut off a
whole world of potentially useful functionality. Obviously it also applies
to things other than presence i.e. subscribing to the state of a production
line could be used to return multiple readings from various sites along the
line, rather than subscribing to each sensor individual.

James