Subject: [Sipping] RE: Sipping digest, Vol 1 #172 - 5 msgs

From: "Sriram Parameswar" <[email-masked]>
Date: Mon, 5 Nov 2001 12:10:24 -0600

Robert;

I agree with you - that the 'empty or neutral' NOTIFY does not buy us
anything, and we should probably eliminate it. However we should retain the
semantics that 202 means Authenticated but not Authorized and a 200 OK
response to SUBSCRIBE as being both Authenticated and Authorized. In either
case there is no requirement for an immediate NOTIFY (there may not be a
reportable state associated with the subscribed object).

On the flip side, a discussion on the SIMPLE list (Adam contributed)stated
that the immediate NOTIFY formed part of a 'Three way handshake'. A
combination of signals results in a 3-way handshake as follows:
	* SUBSCRIBE
	* 202-NOTIFY
	* 200 OK for the NOTIFY

I would contend that a 3-way handshake is _not_ necessary.

Regards,

Sriram

__________________________________________
Sriram Parameswar              Phone: 972-685-8540
Interactive Multimedia Server (IMS) Fax: 972-685-3563
Nortel Networks, Richardson USA  Email: [email-masked]

Message: 1
From: "Fairlie-Cuninghame, Robert" <[email-masked]>
To: "[email-masked]'" <[email-masked]>
Cc: "[email-masked]'" <[email-masked]>
Date: Mon, 5 Nov 2001 03:24:18 -0800
charset="iso-8859-1"
Subject: [Sipping] Immediate NOTIFIES change in sip-events-01

Hi Adam,

The new PDF format looks good.

I wish to discuss the following section:

8.3 Immediate notifies

There has been discussion, but no consensus, on the issue of whether each
SUBSCRIBE must have an immediate NOTIFY message sent in response. In
attempts to follow the prevailing sentiment, this draft had become
inter-nally inconsistent.

This version of this document has eliminated these inconsistancies by
requir-ing notifiers always to send a NOTIFY immediately upon receiving a
SUB-SCRIBE. This decision does not necessarily represent group consensus,
and further discussion may be warranted.

---

As Adam rightly says in a later section, this burdens Event packages with
have to support and fake/dummy NOTIFIES while authorization is pending. [And
just makes things plain messy!] 

Firstly I address these questions to the list as a whole [since Adam is just
documenting list consensus].

So what information is the immediate NOTIFY providing? None. We have a 202
Accepted that informs the subscriber that the SUBSCRIBE request is being
processed (and that it may take a non-trivial amount of time). 

The subscriber knows that the subscription is in effect when the first
_real_ NOTIFY arrives, so sending a dummy NOTIFY immediately is actually
confusing things! What is the rationale? 

If this does stay Adam, the rationale needs to be added and the 202 Accepted
response code can be removed as far as I can see.

Regards,

Robert.

---

From: "Sean Olson (EUS)" <[email-masked]>
Date: Mon, 5 Nov 2001 13:09:25 -0600

But the three-way handshake *IS* needed for establishing
legs in the forking scenario. Or has that changed? 
 
/sean

-----Original Message-----
From: Sriram Parameswar [mailto:[email-masked]]
Sent: Monday, November 05, 2001 12:10 PM
To: [email-masked]'; [email-masked]'; [email-masked]'
Subject: [Sipping] RE: Sipping digest, Vol 1 #172 - 5 msgs

Robert; 

I agree with you - that the 'empty or neutral' NOTIFY does not buy us anything, and we should probably eliminate it. However we should retain the semantics that 202 means Authenticated but not Authorized and a 200 OK response to SUBSCRIBE as being both Authenticated and Authorized. In either case there is no requirement for an immediate NOTIFY (there may not be a reportable state associated with the subscribed object).

On the flip side, a discussion on the SIMPLE list (Adam contributed)stated that the immediate NOTIFY formed part of a 'Three way handshake'. A combination of signals results in a 3-way handshake as follows:

        * SUBSCRIBE 
        * 202-NOTIFY 
        * 200 OK for the NOTIFY 

Regards, 

Sriram 

Message: 1 

Hi Adam, 

8.3 Immediate notifies 

--- 

Regards, 

Robert.