Subject: RE: [Simple] 200 vs. 202

From: "Brian Stucker" <[email-masked]>
Date: Thu, 1 Nov 2001 12:52:09 -0600

Forking interactions, for one. The NOTIFY is used to clear out the
subscriptions that may have been created on nodes that the SUBSCRIBE got
forked to, but whose response was not forwarded back to the UAC that sent
the original SUBSCRIBE.

202 Pending means you've been authenticated, but not authorized yet. You
can't send back a dummy (meaning a NOTIFY containing a message body) back,
because that's how you signal to the subscriber that their subscription has
been authorized finally (authorization triggers a NOTIFY with a message
body). Thus, sending a NOTIFY back that is empty takes care of the 3-way
handshake requirement, but doesn't trick the user into thinking that a
subscription was authorized when it wasn't.

You way basically causes the client to ping the network incessantly asking
if their subscription has been authorized yet: "Am I authorized yet?", "Am I
authorized yet?", "Am I authorized yet?", "Am I authorized yet?".... Seems
wasteful, given that you can simply send back an empty NOTIFY, and be done
with it. Your solution also does not take care of cleaning up forking
interactions if I understand it correctly.

The three-way handshake is in the events draft, and it works. The only issue
that I can see are getting the presence and watcherinfo drafts on board with
what the events draft has set forth, and just clarifying the text in the
events draft a little. It's not a big change in my view.

Regards,

Brian
-----Original Message-----
From: Moran Tim (NET/Dallas) [mailto:[email-masked]]
Sent: Thursday, November 01, 2001 11:36 AM
To: Stucker, Brian [NGB:B621:EXCH]; Ngo, Dai (c); 'Brazier Lachlan';
adam.roach; James Undery; 'ext Paul Kyzivat'; Jonathan Rosenberg
Cc: simple
Subject: RE: [Simple] 200 vs. 202

To me the term Pending (as in 202 Pending) says hold on I can not answer
right now. Sorry, but I just don't see the justification in the immediate
dummy message to the receiver of the 202. I understand (think I do) that the
empty Notify request is sent so that the notifier can know that the 202 was
received because it causes a 200 from Subscriber to Notifier. 4 messages to
do a 3 way handshake. 

It would appear the assumption is that 3-way handshake is required. What is
wrong with the subscriber timing out on receiving a response from the
notifer (200 or 202) and resending the subscribe? That is, what is wrong
with a  two-way handshake with a timer?

Tim M.
-----Original Message-----
From: ext Brian Stucker [mailto:[email-masked]]
Sent: Thursday, November 01, 2001 10:49 AM
To: Ngo, Dai (c); 'Brazier Lachlan'; Moran Tim (NET/Dallas); adam.roach;
James Undery; 'ext Paul Kyzivat'; Jonathan Rosenberg
Cc: simple
Subject: RE: [Simple] 200 vs. 202

The wording there can be taken several ways, and probably needs to be
clarified. We really need to be talking about two notifications at the point
at which a pending subscription comes in: notifying the client that has a
event-package.winfo subscription, and notifying the client that is
requesting the new event-package subscription (where in this case,
event-package is likely to be "presence").

I would argue that you should send an empty NOTIFY to the "presence"
subscription, and send a NOTIFY to the "presence.winfo" subscriber telling
them that the subscription is waiting for their authorization. If the
subscription is a refresh of the pending "presence" subscription, then you
need to send an empty NOTIFY to the "presence" subscription, but it's a MAY
notify on the "presence.winfo" side (the renotification may not be
particularly useful).

I think the new version of the events draft is supposed to be sent out
today, so maybe that'll provide more clarification.

Thoughts?

Regards,

Brian Stucker
-----Original Message-----
From: Ngo, Dai (c) [mailto:[email-masked]]
Sent: Thursday, November 01, 2001 10:27 AM
To: Stucker, Brian [NGB:B621:EXCH]; 'Brazier Lachlan'; Moran Tim
(NET/Dallas); adam.roach; James Undery; 'ext Paul Kyzivat'; Jonathan
Rosenberg
Cc: simple
Subject: RE: [Simple] 200 vs. 202

While reviewing the draft "draft-ietf-simple-winfo-package-00.txt" in the
section 3.6.1 "The Watcherinfo State Machine" it says, "If, when a
subscription arrives, there is no authorization policy in existence, the
subscription moves into the pending state. In this state, the server is
awaiting an authorization decision. *No notifications are generated*, but
the subscription FSM is maintained."
It seems to me that the above statement contradicts with what we are saying
here, that an empty notification is needed to complete the three-ways
handshake.
 
How do we reconcile this conflict?
 
-- Dai