Jeroen van Bemmel wrote:
> The full list of dialog creating requests is: INVITE, 
> SUBSCRIBE, NOTIFY, 
> REFER

I'm not convinced about NOTIFY (the other three I completely agree with).

I am aware of the 'out-of-dialog' NOTIFY messages used by some UAs, but
I don't think they really count as dialog-creating.  RFC3265 is somewhat
evasive in section 3.2:

   NOTIFY messages are sent to inform subscribers of changes in state to
   which the subscriber has a subscription.  Subscriptions are typically
   put in place using the SUBSCRIBE method; however, it is possible that
   other means have been used.

   If any non-SUBSCRIBE mechanisms are defined to create subscriptions,
   it is the responsibility of the parties defining those mechanisms to
   ensure that correlation of a NOTIFY message to the corresponding
   subscription is possible.

I don't think I could read this as 'NOTIFYs can create dialogs' unless
I squint really hard.  It is more easily read as permitting REFER to do
what it does, or allowing older devices to continue to send MWI NOTIFYs
without an explicit SUBSCRIBE.

I'd be interested in any references to prove me wrong though.

Regards,

Michael

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