Subject: [Sip] Comments on draft-rosenberg-sip-reg-00

From: BECKMANN MARK <[email-masked]>
Date: Thu, 25 Jul 2002 14:43:25 +0200

Hi Jonathan,

in your draft on the event package for registrations, you proposed the
following FSM for the contacts registered with an adress of record:

                                 +------+                                 
                                 |      | refreshed                       
                                 |      |                                 
                                 V      |                                 
    +------------+            +------------+            +------------+    
    |            |            |            |            |            |    
    |    Init    |----------->|   Active   |----------->| Terminated |    
    |            |            |            |            |            |    
    +------------+ registered +------------+ expired    +------------+    
                   created                   deactivated                  
                                             probation                    
                                             unregistered                 
                                             rejected                     

In section 3.1 it is described that in case an administrator wants a device
to re-authenticate, the registration is terminated and the device is
notified, e.g. by setting the event parameter to "deactivated".

First of all, I can't see a big difference between the two events "expired"
and "deactivated". "Deactivated" seems to be part of the "expired" event. In
both cases the contact may be re-registered. It doesn't seem very important
whether the registration is moved to the terminated state because it has
expired or because it has been deactivated.

Secondly, I think in case an administrator wants a device to
re-authenticate, the registration of the corresponding contact should not
move to the terminated state. Instead, another event (for example
"re-authenticate") similar to the "refresh" event should be introduced. When
this event occurs, the device is notified and the duration for which the
contact remains registered is reduced and if the device fails to
re-register, the registration is moved to the terminated state e.g. via the
"expired" event.

Thus, the FSM would look like:
                                                                          
                                 +------+                                 
                                 |      | refreshed                       
                                 |      | re-authenticate

                                 V      |                                 
    +------------+            +------------+            +------------+    
    |            |            |            |            |            |    
    |    Init    |----------->|   Active   |----------->| Terminated |    
    |            |            |            |            |            |    
    +------------+ registered +------------+            +------------+    
                   created                   expired               
                                             probation            
                                             unregistered           
                                             rejected               

Best regards,

Mark

Mark Beckmann			Siemens AG

ICM MP P PS 4S2
P.O.Box 100702			phone: +49 (5341) 906 1814
D-38228 Salzgitter   		fax:   +49 (5341) 906 2010

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---

From: "Dean Willis" <[email-masked]>
Date: Mon, 29 Jul 2002 15:00:26 -0500

Mark said:
> re-authenticate, the registration of the corresponding 
> contact should not move to the terminated state. Instead, 
> another event (for example
> "re-authenticate") similar to the "refresh" event should be 
> introduced. When this event occurs, the device is notified 
> and the duration for which the contact remains registered is 
> reduced and if the device fails to re-register, the 
> registration is moved to the terminated state e.g. via the 
> "expired" event.

As I understand it, we want a UA to still work "properly" for a while
after it has been asked to reauthenticate.

If the proxy actually terminates the registration, one might assume it
deletes the associated contact from its storage. An incoming request
(say, INVITE) that arrives at the proxy between this deletion and the
reinsertion of the contact following a new registration from the UA
would then be handled as if the UA was not registered (as in "turned
off").

So, I believe Mark's concerns here are valid and we do need another
state in the FSM.

--
Dean