IPP Mail Archive: RE: IPP>NOT latest notify-poll document [t

IPP Mail Archive: RE: IPP>NOT latest notify-poll document [t

RE: IPP>NOT latest notify-poll document [time window NOT = lease time]

From: Hastings, Tom N (hastings@cp10.es.xerox.com)
Date: Wed Mar 08 2000 - 12:59:18 EST

  • Next message: Hastings, Tom N: "RE: IPP>NOT latest notify-poll document[window of events NEED NOT be a constant for Printer]"

    I think that the window of time for holding events has to be different from
    the "lease time" for the Subscription object. For example, an infinite
    lease for the subscription object is allowed. This would mean that the
    number of events coming back in each poll would grow forever.



    The IPP notification specification [ipp-ntfy] is an OPTIONAL extension to
    IPP/1.0 and IPP/1.1 that requires the definition of one or more delivery
    methods for dispatching event notification reports to Notification
    Recipients. This document describes the semantics and syntax of the 'ipp'
    event notification delivery method. For this delivery method, the client
    uses an explicit IPP Get-Notifications Printer operation in order to request
    (pull) event Notifications from the IPP Printer.
    When a Printer supports the 'ipp' delivery method, it holds each
    Notification event for a certain length of time. The amount of time is
    called the "lease time" and it is the same for all events in a Printer. If
    a Notification Recipient does not want to miss events, the time between
    consecutive polling of Subscription objects must be less than the lease
    time. The Get-Notifications request indicates whether the client wants to
    receive all pending events Notifications for (1) any Subscription for which
    the client is the owner, (2) any Subscription associated with a Job or (3) a
    particular Subscription object. With the Get-Notifications operation, the
    Printer returns all existing Notifications along with two time intervals.
    One specifies the length of the lease for all future events and the other
    specifies the recommended interval to wait to the next Get-Notifications
    operation. The second time interval is less than the first.
    The Printer may keep the channel open if the recommended interval is
    sufficiently short, but in any case the client performs a new
    Get-Notifications operation each time it wants more Notifications. Since
    the time interval between consecutive client requests is normally less than
    the lease time,consecutive responses will normally contain some events that
    are identical. The later ones in the previous response will become the
    earliest in the next response. The client is expected to filter out these
    duplicates which is easy to do because of the sequence number in each
    -----Original Message-----
    From: Herriot, Robert [mailto:Robert.Herriot@pahv.xerox.com]
    Sent: Tuesday, March 07, 2000 19:47
    To: ipp@pwg.org
    Subject: IPP>NOT lastest notify-poll document

    I just downloaded the latest notify-poll document.

    It is


    We may discuss the issues at the IPP teleconference tomorrow.

    Bob Herriot

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