Subject: [sipcore] Initial NOTIFY without state information

From: <[email-masked]>
Date: Tue, 4 Aug 2009 13:13:59 +0200

What should a notifier send in its initial NOTIFY if it doesn't have valid state information?

Do end devices handle NOTIFYs with an empty body properly?

What's the "neutral state" for MWI simple-message-summary?

RfC 3265 states:

'If the resource has no meaningful state at the time that the SUBSCRIBE message is
processed, this NOTIFY message MAY contain an empty or neutral body. See section
3.2.2. for further details on NOTIFY message generation.'

Sigh. This paragraph does not contain much useful information for my problem. How do I debug a
customer's problem, if the notifier sends 'made up' state information instead of indicating that
it currently has no information at all? Sending an empty or neutral state is purely optional, I can't
rely on it.

The paragraph doesn't even mention the case where the notifier loses state information during an
ongoing subscription. This may happen when a PUBLISH expires, or the notifier loses a database connection.

What is a "neutral state"?
RfC 3265:
'Documents which define new event packages MUST define
this "neutral state" in such a way that makes sense for their application'

If they only would. Eg. RfC 3842 (MWI) doesn't seem to contain any hint about it.

Cross-posted to contribute to the ongoing discussion of 3265bis.

Regards,

Wolfgang Beck

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