I'll add an ISSUE to the agenda about whether we should try to add a way for
the client to indicate which events he already has so that the Printer can
avoid returning duplicates.
However, remember this problem is only for using Get-Notifications in Event
No Wait mode (polling). For Event Wait mode, there aren't any duplicate
events returned to a Notification Recipient. If we think that the majority
of use will be with Event Wait Mode, then we don't need to solve the problem
for Event No Wait Mode.
Tom
-----Original Message-----
From: Marty Joel [mailto:mjoel at netreon.com]
Sent: Friday, July 27, 2001 14:42
To: ipp at pwg.org
Subject: Re: IPP> Duplicate ippget events
Hi Michael,
I agree, but that means the client will have to send a list of
notify-subscription-id / notify-sequence-number pairs (although I realize
there would usually only be one).
Marty
Michael Sweet <mike at easysw.com>@pwg.org on 07/27/2001 12:43:56 PM
Sent by: owner-ipp at pwg.org
To: Marty Joel <mjoel at netreon.com>
cc: ipp at pwg.org
Subject: Re: IPP> Duplicate ippget events
Marty Joel wrote:
>> Hi Michael,
>> I agree with everything you've said.
>> Actually, notify-sequence-number is what should be used by the client to
> ignore duplicates. For each subscription that matches its
> Get-Notifications (usually only 1 subscription), it needs to know that
> subscription ID and the last notify-sequence-number it received. That
> requires very little work on the part of the client.
> ...
Hmmm, from an implementation standpoint, it would be better if the
client could send the last sequence number is has received to the
server, so the server would only have to send events whose sequence
number is > the one provided. E.g., a client sends a server the
"notify-sequence-number" attribute in the Get-Notifications request,
and the server responds only with those events that have a higher
sequence number. This would also reduce the bandwidth used...
Thoughts?
--
______________________________________________________________________
Michael Sweet, Easy Software Products mike at easysw.com
Printing Software for UNIX http://www.easysw.com