Subject: Re: [Sipping] New I-D - SIP Subscription Mobility using SUBSCRIBE withReplaces Header

From: Álvaro Canivell García de Paredes<[email-masked]>
Date: Fri, 27 Jan 2006 18:24:26 +0100

I might be wrong, but... if we are speaking about service mobility (in 
which the user changes the terminal device - e.g. PC to SmartPhone or to 
PDA), it can be complex for the new device to distinguish wether the 
user wants to update subscription, or is subscribing for the first time 
(i.e. send an UPDATE or send a SUBSCRIBE). The easiest solution may be 
simply, to start a new subscribe process. The server will realize that 
it is a subscription refresh after reconginzing  the SIP address of the 
user.

Hope it helps

Álvaro

>Message: 1
>Date: Fri, 27 Jan 2006 07:43:08 +0100
>From: "Jeroen van Bemmel" <[email-masked]>
>Subject: Re: [Sipping] New I-D - SIP Subscription Mobility using
>	SUBSCRIBE	withReplaces Header
>To: "Jentz Brad-CBJ002" <[email-masked]>, <[email-masked]>
>Cc: Coulas Michael-MCOULAS1 <[email-masked]>,	Horvath
>	Bob-BHORVAT1 <[email-masked]>
>Message-ID: <003901c6230c$ef7e4f50$6402a8c0@BEMBUSTER>
>Content-Type: text/plain; format=flowed; charset="iso-8859-1";
>	reply-type=original
>
>Brad,
>
>One brief question : why couldn't the mobile device send an UPDATE over the 
>new network (with new Contact), instead of terminating / replacing its 
>subscriptions?
>
>Jeroen
>  
>

_______________________________________________
Sipping mailing list  https://www1.ietf.org/mailman/listinfo/sipping
This list is for NEW development of the application of SIP
Use [email-masked] for questions on current sip
Use [email-masked] for new developments of core SIP

---

From: Horvath Bob-BHORVAT1 <[email-masked]>
Date: Fri, 27 Jan 2006 12:38:45 -0600

Álvaro Canivell García de Paredes wrote:
> which the user changes the terminal device - e.g. PC to SmartPhone or 
> to PDA), it can be complex for the new device to distinguish wether 
> the user wants to update subscription, or is subscribing for the first 
> time (i.e. send an UPDATE or send a SUBSCRIBE). 

That is out of scope for this draft. We are assuming there are ways for 
the device to figure this out.  In the device mobility case, it is the 
same device, so it is clearly aware of whether it is an update or a new 
subscription.  Devices can also be REFERed to perform a SUBSCRIBE with 
Replaces, in which case it is also clear that this is replacing an 
existing subscription and not creating a new one.  The problem being 
solved is how to move a subscription.

> The easiest solution may be simply, to start a new subscribe process. 
> The server will realize that it is a subscription refresh after 
> reconginzing  the SIP address of the user.

I am not sure the notifier should assume it is a subscription refresh 
based on the SIP address of the user.  Users should be allowed to have 
multiple subscriptions if they desire.  Re-freshing subscriptions is 
handled nicely with 3265, but only over an existing dialog. Whether a 
SUBSCRIBE is meant to add to or replace an existing subscription is 
something that should be explicitly stated and not assumed.

Bob Horvath

>> One brief question : why couldn't the mobile device send an UPDATE 
>> over the new network (with new Contact), instead of terminating / 
>> replacing its subscriptions?
>>
>> Jeroen
>>  
>>
>
>