[Kamailio-Users] Presence_Dialoginfo versioning

[Olle E. Johansson]

15 dec 2009 kl. 09.59 skrev Daniel-Constantin Mierla:

> Hello,
> 
> On 12/15/09 2:20 AM, kamailio.org at spam.lublink.net wrote:
>> 
>> Alright, I finally found the proper RFC, http://www.rfc-editor.org/rfc/rfc4235.txt
>> 
>> Section 4.1 :
>> 
>> "version: This attribute allows the recipient of dialog information  documents to properly order them. Versions start at 0, and increment by one for each new document sent to a subscriber. Versions are scoped within a subscription. Versions MUST be representable using a non-negative 32 bit integer."
>> 
>> Versions are scoped within a subscription, so when a new subscription is started, ( after the 1 hour expiry ), the version should be reset as it is a new subscription and therefore a new scope ?
>> 
>> When the subscription expires, is it renewed or is a new subscription created? Is the scope separate, or is it the same subscription updated?
> 
> I think this is another questionable thing about SIP. IMO, it is same subscription if the dialog attributes do not change (call-id, from tag and to tag). But others can argue is it a new subscription. Anyone else on this one?
> 
The proper RFC for generic subscription/notify questions is RFC 3265.

"3.1.1 Subscription Duration
SUBSCRIBE requests SHOULD contain an Expires header (defined in SIP [2]). This expires value indicates
the duration of the subscription. In order to keep subscriptions effective beyond the duration communicated
in the Expires header, subscribers need to refresh subscriptions on a periodic basis using a new
SUBSCRIBE message on the same dialog as defined in SIP [2]"

This indicates to me that it's the same subscription as long as you refresh it. 

RFC4235 refers to RFC 3265 for general terminology about subscriptions.

/O