15 Dec
2009
15 Dec
'09
11:12 a.m.
15 dec 2009 kl. 09.59 skrev Daniel-Constantin Mierla:
Hello,
On 12/15/09 2:20 AM, kamailio.org(a)spam.lublink.net wrote:
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
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?