[Standards] Client Acknowledgement of Subscription State Change Notifications
ian.paterson at clientside.co.uk
Sun Mar 4 21:28:08 UTC 2007
Section 9.4 of RFC 3921 (Appendix B.4 of RFC 3921bis) states that "A
server MAY require the recipient to acknowledge receipt of all state
change notifications... In order to require acknowledgement, a server
SHOULD send the request or notification to the recipient each time the
recipient logs in, until the recipient acknowledges receipt".
The acknowledgement of subscription requests is clearly necessary, but
can anyone please tell me why servers are permitted (but not encouraged)
to insist on acknowledgements for the other three notifications?
A couple of suggestions for 3921bis:
1. Since a client has no way of discovering if the server requires an
acknowledgement or not, it should always acknowledge notifications. So
perhaps RFC 3921bis could highlight the importance of clients responding
by also specifying something like: "The recipient SHOULD/MUST affirm or
deny every notification to prevent some servers flooding it with an
ever-increasing number of notifications upon each login."
2. Hopefully someone will enlighten me, but if not, perhaps we could
also consider depricating this repeated notification behaviour?
Apologies in advance if this subject has already been discussed with
regard to 3921bis.
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