Subject: RE: [SIP] NOTIFY request MUST contain an Expires header?

From: Adam Roach <[email-masked]>
Date: Sat, 8 Jun 2002 21:28:35 -0400

> -----Original Message-----
> From: Jonathan Rosenberg [mailto:[email-masked]]
> 
> Tan Ya-Ching ICM N PG U ID A 1 wrote:
> > 
> > Thanks for the answer.
> > 
> > In that case, shouldn't the "expires" parameter in the
> > Subscription-State
> > header in NOTIFY carry the same MUST strength as for 
> Expires header in
> > 200
> > OK response to SUBSCRIBE, instead of just a SHOULD (second last
> > paragraph of
> > 4.2.2 of draft-sip-events)? Section 4.2.4 'Subscriber 
> NOTIFY Behavior'
> > also
> > talks about the "expires" parameter with "If the Subscription-State
> > header
> > also contains an "expires" parameter...", but what if it 
> does not ? Can
> > a
> > NOTIFY request which matches (according to 4.3.4) the 
> SUBSCRIBE request
> > create a subscription and a new dialog if its 
> Subscription-State does
> > not
> > contain an "expires" parameter ?
> 
> Yes, this is a good point. I believe this is probably an error in
> sip-events, and that the expires parameter needs to be 
> present with MUST
> strength.
> 
> Adam?

The thought around the current way it is worded is that it's not
strictly necessary (or even all that useful) to include that information
after the first NOTIFY has been sent.

I agree that this should be spelled out more clearly, and possibly
have a MUST strength for any dialog-establishing NOTIFY messages.
To avoid having the draft kicked out of the publication process,
we'll have to fix this in the next go-around.

/a

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