Subject: AW: [Simple] 200 vs. 202

From: Brazier Lachlan <[email-masked]>
Date: Tue, 6 Nov 2001 10:30:24 +0100

Hello,

comments inline.

> 
>  * there can be multiple PUA for a presentity, of course. If 
> any of them can
> act as presence agents for the subset of presence data they 
> know of, they
> can register with the presence server indicating that 
> (methods=SUBSCRIBE)
> 

Agreed.

>  * if a presence server is aware of multiple PUA for a presentity, the
> presence server SHOULD act as a PA (and therefore not fork 
> subscriptions)

So, when I register with the presence server (method=SUBSCRIBE), I can't be
sure to be the only one, whitch would mean I don't know if my PA or the
presence server "PA" will handle the SUBSCRIBE requests. I'm not sure if
this would be a problem. Any thoughts?

Wouldn't it make sense to fork and wait for all responses? Then the presence
server could be sure to forward the right response. You can always set a
timer, to handle missing responses as errors. 

>  * a subscriber SHOULD accept all NOTIFY requests generated 
> by a particular
> subscription (i.e., not reject all but the one matching the 2xx to
> SUBSCRIBE), and then compose the presence data from each 
> notification into a
> complete presence document

Agreed, because:
Think of the situation, when a proxy forks the SUBSCRIBE request to B1 and
B2. Lets say both awnser with a 200 Ok followed with an immediate NOTIFY.
The proxy might drop one 200 Ok, still you have 2 NOTIFY's on the line. You
can only reject a NOTIFY from B2, when you received a 200 Ok from B1. If the
NOTIFY from B2 was quicker than the 200 Ok from B1, you need to wait for the
200 Ok (SUBSCRIBE) before responding to the first NOTIFY. After a while you
will get a NOTIFY from B1. It's even worse, when the NOTIFY from B1
overtakes it's 200 Ok.

Disagreed, because:
If you accept all NOTIFY's, you MUST be absolutely sure, they contain the
same presence status. Otherwise you might run into inconsistent presence
data, which you can't solve (B1 is online, B2 is going for a coffee, etc.)
The solution with accepting only one NOTIFY was nice, because you didn't
need to worry. It's just simpler.

If I missed something, sorry and please tell me!

Cu
Lachlan
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