Subject: [Sip] Comments on draft-ietf-sip-subnot-etags-00

From: Qian Sun <[email-masked]>
Date: Mon, 16 Jul 2007 16:19:15 +0800

Hi,

As this draft mentioned, the presence rules may affect the views of the resource state. If the presence rules of presentity are modified, all of etags for this presentity have to be abandoned. Or the PS has to evaluate whether each etag still is valid. 

For filtering, there is similar problem:
http://www1.ietf.org/mail-archive/web/sip/current/msg19724.html

These are difference between HTTP and SIP events framework.

Cheers,
Qian

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From: Aki Niemi <[email-masked]>
Date: Tue, 17 Jul 2007 13:30:17 +0300

Hi Qian,

ext Qian Sun wrote:
> Hi,
> 
> As this draft mentioned, the presence rules may affect the views of
> the resource state. If the presence rules of presentity are modified,
> all of etags for this presentity have to be abandoned. Or the PS has
> to evaluate whether each etag still is valid.

I'm not sure I understand what it is that should be added to the draft
to clarify this issue.

There are all sorts of events that drive the internal state machine of
the PS, or more generally the server of any event package. For instance,
authorization rules might change, the resource state might change, and
those changes might or might not be visible to the subscriber. However,
those details are of no concern of the subnot-etags draft, IMO.

All that matters is that if the resource to which the subscriber
subscribed changes, then the entity-tag changes as well. What "change"
means here should be an implementation detail for every event package to
figure out. IOW, I don't think it belongs in the subnot-etags draft.

> These are difference between HTTP and SIP events framework.

Even HTTP resources can be dynamically generated, their access
controlled using an authorization framework of considerable complexity
and have many different views for different agents that access them.

So I don't think HTTP resources and SIP resources are that much
different in this respect.

Cheers,
Aki