Subject: RE: [Simple] Re: draft-levin-simple-interdomain-reqs-02

From: "Tim Rang" <[email-masked]>
Date: Tue, 15 Mar 2005 09:34:21 -0800

In my experience, the notifier forced resubscribe is not far fetched at
all.  I've seen several implementations that deal with fault tolerance
and failure recovery by just setting the subscription lifetime to a
short "tolerable" value, letting the resubscribe restore the lost state.
If my domain is federating with a peer domain that does this, I don't
want it to hamper my server's scalability.

Thanks,
Tim

>Yes, I see how that could be a problem. However, 3265 has a provision
to
 >deal with that:
 >
 >    The notifier MAY also check that the duration in the "Expires"
header
 >    is not too small.  If and only if the expiration interval is
greater
 >    than zero AND smaller than one hour AND less than a notifier-
 >    configured minimum, the notifier MAY return a "423 Interval too
 >    small" error which contains a "Min-Expires" header field.  The
"Min-
 >    Expires" header field is described in SIP [1].
 >
 >Of course the interval is one hour rather than two. But That doesn't
 >seem so awful. (I am guessing that the value of two hours that you use
 >was an arbitary one.)
 >
 >The only thing that doesn't deal with is a notifier that forces a
 >subscription to have too small a value. That seems somewhat far
fatched.
 >If you feel it is a plausible problem, then you could consider
proposing
 >a revision to 3265 allowing a Min-Expires header in a SUBSCRIBE
request.
 >
 >> We could potentially use something akin to Aki's throttling proposal
to
 >> allow this to be negotiated, I suppose, but I don't know if that
adds
 >> more complexity than is strictly necessary.

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From: Paul Kyzivat <[email-masked]>
Date: Mon, 21 Mar 2005 20:11:23 -0500

I thought I had answered this, but I guess not.

> want it to hamper my server's scalability.

As I suggested earlier, if you feel it is a plausible problem, then it 
would make sense to propose a revision to 3265 allowing a Min-Expires 
header in a SUBSCRIBE request.

	Paul