Hi, I have read may times the thread "Calculation of subscription duration", but implementing rfc 3266 procedures I still have some doubts.
Assuming that subscriber and notifier can agree about the subscription duration with subscribe/2xx/notify, is there any reason for the notifier to change the subscription duration with a notify NOT triggered by a subscribe/refresh. This notify can be triggered by any event at the notifier (presence state change, subscription policy change, ...) but I cannot find a 'reasonable' reason to shorten expires time, even if it is possible to do that. If the subscription is not longer valid the notifier can send expires = 0. Actually the notifier decides the expiration time (using subscriber proposal), but it can carry the expiration time both in 2xx (Expires header mandatory) and in notify. It seems that the responsibility is not well distributed considering that notify is sent soon after the 2xx response: 2xx and notify can carry the subscription duration indipendently, and the values can be different; this leads to some problems already discussed in the other thread. thought #1 **If there is no reason for the notifier to shorten the expires time after agreement (subscribe/2xx/notify phase) the expire time carried by notify could be 'only informational', to alert the subscriber about the remaining time at the notifier, and subscription agreement can be left to subscribe/2xx. thought #2 Otherwise we can use expires time carried by 2xx response to subscribe/refresh as informational and wait for notify to decide the agreed subscription time (this allows notifier to change subscription duration whenever it wants) I would like to know your comments about this. Thanks. -- Marco Ambu Abbeynet S.p.a. <http://www.abbeynet.it> E-mail: [EMAIL PROTECTED] VoIP address: <sip:[EMAIL PROTECTED]> _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
