Hi,
I have a few question regarding interpretation of RFC 3265. Paragraph
3.2.2 states that:
If the NOTIFY request fails (as defined above) due to a timeout
condition, and the subscription was installed using a soft-state
mechanism (such as SUBSCRIBE), the notifier SHOULD remove the
subscription.
...
If the NOTIFY request fails (as defined above) due to an error
response, and the subscription was installed using a soft-state
mechanism, the notifier MUST remove the corresponding subscription.
...
If a NOTIFY request receives a 481 response, the notifier MUST remove
the corresponding subscription even if such subscription was
installed by non-SUBSCRIBE means (such as an administrative
interface).
But it doesn't firmly assert whether the reaction should be the same to
failed immediate and non-immediate NOTIFY. If an ordinary
(non-immediate) NOTIFY communicating the resource state change fails,
should the notifier remove the subscription or not? Or we can choose
whatever behavior makes sense for the particular application?
It may be no good for long-living subscriptions found in such services
as BLF if the application removes the subscription after failed
non-immediate NOTIFY. It means that brief network or systems
malfunctioning can disrupt the service. OTOH, NOTIFYs are sent on the
same dialog and I'm not sure we could tolerate the error response and
keep the dialog active.
I guess that if failed non-immediate NOTIFY should be considered the
reason for subscription termination, it's particularly important that
notifier sends, as per RFC, a NOTIFY message with a "Subscription-State"
value of "terminated" to inform it that the subscriber that subscription
is being removed. Please let me know your thoughts. Thanks,
--
Sincerely,
Andrew Pogrebennyk
_______________________________________________
Sip-implementors mailing list
[email protected]
https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
