IPP Mail Archive: IPP> Misplaced attributes

IPP Mail Archive: IPP> Misplaced attributes

IPP> Misplaced attributes

From: Zehler, Peter (PZehler@crt.xerox.com)
Date: Mon Mar 12 2001 - 18:04:37 EST

  • Next message: Mike Bartman: "RE: IPP> Misplaced attributes"

    I have had some internal discussions around an issue I would like to resolve
    across the IPP WG.

    ISSUE: An IPP Client sends a print request with the
    "ipp-attribute-fidelity" attribute containing a value of 'true'. The client
    also supplies the job template attribute "sides" with a value of
    'two-sided-long-edge'. The IPP Printer does not support two sided printing.
    The IPP Client software generates the request but put the
    "ipp-attribute-fidelity" in the job attributes group instead of the
    operational attributes group. What should the Printer do?

       A) Reject the request with 'client-error-bad-request' since
    "ipp-attribute-fidelity" is in the wrong group.

       B) Reject the job because the printer does not support two sided
    printing. The IPP Printer would accept "ipp-attribute-fidelity" even though
    it is in the wrong group. The printer would return a
    "client-error-attributes-or-values-not-supported' error and return the
    "side" attribute and value in the unsupported attribute group.

       C) Accept the job and print it substituting 'one-sided'. The IPP Printer
    uses the defaulted value (i.e. 'false' ) for "ipp-attribute-fidelity" since
    it was not an operational attribute. The return code would be
    'successful-ok-ignored-or-substituted-attributes' and the "sides" and
    "ipp-attribute-fidelity" would be returned as unsupported attributes. (i.e.
    "ipp-attribute-fidelity" is not a supported job template attribute)

    As an IPP Printer implementer I would chose C. The response informs the
    client that it is in error. The Printer is forgiving and the job is
    printed. The extensibility of IPP is maintained.

    The Implementer's guide with need to be updated to provide a recommendation
    on how to handle "misplaced" attributes. There is currently a clause that
    lumps "misplaced" attributes with missing or duplicate attributes. (section


    By the way my email address has changed from Peter.Zehler@usa.xerox.com to

                                    Peter Zehler
                                    Xerox Architecture Center
                                    Email: PZehler@crt.xerox.com
                                    Voice: (716) 265-8755
                                    FAX: (716) 265-8792
                                    US Mail: Peter Zehler
                                            Xerox Corp.
                                            800 Phillips Rd.
                                            M/S 139-05A
                                            Webster NY, 14580-9701

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