Subject: [Simple] presence event package - generation of notify requests

From: <[email-masked]>
Date: Fri, 14 Jul 2006 13:34:56 +0200

Hello, 

I would like to get some clarification about notifications.

In RFC3856 par. 6.7. Notifier Generation of NOTIFY Requests

...
A PA MAY send a NOTIFY at any time.  Typically, it will send one when
   the state of the presentity changes.  The NOTIFY request MAY contain
   a body indicating the state of the presentity.  The times at which
   the NOTIFY is sent for a particular subscriber, and the contents of
   the body within that notification, are subject to any rules specified
   by the authorization policy that governs the subscription.
...

If PA does not deliver the notification at all, is it still valid
behavior? 

The situation I have in mind: 
There is rate control mechanism and then filtering mechanism on the PA
(rate control is applied first due to implementation decision). A
resource is subscribed. The state of the resource changes quickly from A
to B (notification N1 is generated) and then back to A (N2). Lets say
that N1 is caught by rate control. N2 arrives and replaces N1 in the
rate control. N2 is passed to filtering and is discarded because the
client is not interested in changes from B to A (but it is interested in
changes from A to B). 

In my opinion this behavior is not valid because the subscriber can miss
the information it seeks, but the specification is not very specific on
this. What is your opinion?

Thank you

Silvestr Peknik
Software Specialist
TietoEnator

_______________________________________________
Simple mailing list
[email-masked]
https://www1.ietf.org/mailman/listinfo/simple

---

From: Jonathan Rosenberg <[email-masked]>
Date: Mon, 17 Jul 2006 10:12:28 -0400

inline.

> If PA does not deliver the notification at all, is it still valid

Generally speaking, of course. If privacy filters are on, no 
notifications might ever be generated in some use cases.

> this. What is your opinion?

Rate limiting causes loss of information. If you do it, you run the risk 
of losing things that might be interesting. You cannot have it both ways 
(rate limit notifications and never miss useful data.)

-Jonathan R.

-- 
Jonathan D. Rosenberg, Ph.D.                   600 Lanidex Plaza
Cisco Fellow                                   Parsippany, NJ 07054-2711
Cisco Systems
[email-masked]                              FAX:   (973) 952-5050
http://www.jdrosen.net                         PHONE: (973) 952-5000
http://www.cisco.com