IPP Mail Archive: RE: IPP> Re: Last Call comment to remove r

IPP Mail Archive: RE: IPP> Re: Last Call comment to remove r

RE: IPP> Re: Last Call comment to remove redirect URL and status code from IPPGET

From: McDonald, Ira (imcdonald@sharplabs.com)
Date: Fri Aug 02 2002 - 13:02:01 EDT

  • Next message: Robert Herriot: "Re: IPP> Re: Last Call comment to remove redirect URL and status code from IPPGET"

    Hi Harry,

    You're forgetting how Get-Notifications works. You get back that
    to the (pseudo-printer) Notification server and _that_ server MUST contain a
    Subscription object that is still references by the 'subscription-id'
    by the original simple job subscription.

    But the solution is simple - let all of the managed printers that are
    by one configured Notification server partition their 'subscription-id'
    (each gets say 65,000 subscriptions, which supports 65,000 federated

    This business of the Subscription object referring to a 'printer-uri' and
    'job-id' that are NOT on the Notification server is perhaps a bit odd.

    - Ira McDonald

    PS - Can you guys possibly stop sending HTML email? It takes a _long_ time
    (more than 30 seconds) to open here in MS Outlook 2000 and often gets

    -----Original Message-----
    From: Harry Lewis [mailto:harryl@us.ibm.com]
    Sent: Thursday, August 01, 2002 5:26 PM
    To: Robert Herriot
    Cc: Dennis Carney; hastings@cp10.es.xerox.com; ipp@pwg.org
    Subject: Re: IPP> Re: Last Call comment to remove redirect URL and status
    code from IPPGET

    2b is OK but not necessary. The printer and the redirect location can have
    whatever private understanding they wish to determine how to concoct the
    redirect uri.
    Harry Lewis
    IBM Printing Systems

    "Robert Herriot" <bob@herriot.com>
    Sent by: owner-ipp@pwg.org
    08/01/2002 03:14 PM
            To: <ipp@pwg.org>, Dennis Carney/Boulder/IBM@IBMUS
            cc: <hastings@cp10.es.xerox.com>, Harry
            Subject: Re: IPP> Re: Last Call comment to remove redirect
    URL and status code from IPPGET


    You raise valid points on this issue. It is best not to revisit closed
    issues so late in the process unless there is a bug. I think that the
    time-out issue is NOT a bug (details below), but there may be another issue
    that needs clarification (details at the end of this email).

    Some people have commented that the IPP redirection is lacking a time-out
    which HTTP does have. However, if I understand RFC 2616 correctly, a
    redirection URI is cached by the client only when a Cache-Control or Expires
    header is present. So the default behavior is that a client does not cache a
    redirection URI. We could simply add language to ipp-get that redirection
    URIs SHOULD NOT be cached. An Expires attribute would make a better
    solution, but since only IBM wants this feature, we should keep the solution
    simple and not change past agreements.

    Now that Harry has said that he plans to support this feature, he removes my
    claim about the feature having no value to anyone. If we keep this feature
    then we should leave the ipp-get document unchanged except for the
    clarification that I suggested in the previous paragraph and the one I
    suggest in the next paragraph.

    Now for the other issue with redirection. The Get-Notifications operations
    has a printer-uri argument. What is its value for the Get-Notifications
    operation to the redirected URI. The ipp-get document is silent on this
    issue. Also how does the redirected server know what printer the
    subscription-ids apply to? There are two possible solutions.

    1) The printer-uri attribute's value is the original printer URI that
    responded with the redirection URI. This value tells the redirected server
    what printer the subscription-id belong to.

    2) The printer-uri attribute's value is the redirection URI (of the
    redirected server). In this case either

    2a) the subscription-ids must be unique across all printers served by the
    redirected server or

    2b) the redirection URI must encode the name of the original printer in its

    Solution 2b fits in best with the existing architecture.

    Bob Herriot

    ----- Original Message -----
    From: "Dennis Carney" <dcarney@us.ibm.com>
    To: <ipp@pwg.org>
    Cc: <hastings@cp10.es.xerox.com>; "Harry Lewis" <harryl@us.ibm.com>
    Sent: Thursday, August 01, 2002 8:20 AM
    Subject: IPP> Re: Last Call comment to remove redirect URL and status code
    from IPPGET

    > At the risk of looking like I'm simply taking Harry's side since he and I
    > work together, I'm going to comment nonetheless.
    > This process *does* seem a bit arbitrary to me. I could probably go back
    > through (well, maybe not me, but I'm sure Tom could ;-) any document the
    > PWG has produced looking for things that "don't look right". Then I could
    > bring them up, and possibly get significant support in their
    > "not-looking-right-ness". However, in theory, whatever it is I'm bringing
    > up has already been discussed and decided upon in the past, by a number of
    > people who had their heads clearly focused on the task at hand, unlike
    > where probably fewer people are paying attention, and even those people
    > might not have really had their minds focused on the subject for months
    > (years?).
    > I think if a "problem" is discovered in a document, it should be brought
    > up, as Tom did. However, even if only one person pipes up to explain why
    > it is not a problem (it's a feature! :-), I would think the conversation
    > should end there--a conscious decision was made on the subject and opening
    > up documents to continual re-editing would seem to be a bad precedent.
    > If there is real consensus that this redirect mechanism is a "problem",
    > sure, let's consider getting rid of it. But if the consensus is simply
    > that we're not sure whether anyone is going to use it, I believe we must
    > have more useful things to do with our time than debate this.
    > Just my 2 cents worth...
    > Dennis Carney
    > IBM Printing Systems

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