IPP Mail Archive: RE: IPP> URL - Improved conformance for IP

RE: IPP> URL - Improved conformance for IPP URLs - 1 Feb 2001

From: McDonald, Ira (imcdonald@sharplabs.com)
Date: Fri Feb 09 2001 - 14:06:20 EST

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    Hi Bob,

    Good comments. The case and form 'IPP URL' was chosen to conform
    to existing practice in recent IETF RFCs that define URL schemes.
    The terms section (that equates 'IPP Job' to 'IPP Job object')
    could be used to show the equivalence.

    It is NOT the responsibility of the IPP URL Scheme document to
    enumerate all the IPP protocol attributes that may or must
    contain _only_ an IPP URL. That's the responsibility of the
    RFC 2910/2911 specs. I'll look over the conformance rules.
    I fail to see offhand how conformance rules specifically
    about the use of URLs that have the scheme 'ipp:' (which is
    true throughout this spec when the term IPP URL is used) can
    imply that other schemes are OK to use. Some IPP protocol
    attributes may allow values that do not use 'ipp:' scheme
    but those are NOT IPP URLs by definition.

    Cheers,
    - Ira

    -----Original Message-----
    From: Herriot, Robert [mailto:Robert.Herriot@pahv.xerox.com]
    Sent: Wednesday, February 07, 2001 4:11 PM
    To: McDonald, Ira; 'ipp@pwg.org'; McDonald, Ira
    Subject: RE: IPP> URL - Improved conformance for IPP URLs - 1 Feb 2001

    I have a comment which pertains to 3 rules: 5.1.a, 5.2.a and 5.2.b. Each of
    these rules specifies something about IPP URLs and mentions one IPP
    attribute as an example. Section 5 of RFC 2910 specifies the attributes that
    contain an "ipp-URL".

    But this draft does not make an adequate link between its term "IPP URL" and
    the RFC 2910 term "ipp-URL". Perhaps there should be a more explicit link
    between these two concepts.

    In addition, a reader can infer from 5.1.a, 5.2.a and 5.2.b that a URL with
    a scheme other than "ipp" is OK. RFC 2910 suggests that that certain
    specified attributes can only contain ipp-URLs, but the language is not as
    strong as it could be.

    Bob Herriot

    > -----Original Message-----
    > From: McDonald, Ira [mailto:imcdonald@sharplabs.com]
    > Sent: Thursday, February 01, 2001 4:36 PM
    > To: 'ipp@pwg.org'; 'imcdonald@crt.xerox.com'
    > Subject: IPP> URL - Improved conformance for IPP URLs - 1 Feb 2001
    >
    >
    > Hi folks, Thursday (1
    > February 2001)
    >
    > Based on feedback from Don Wright, Michael Sweet, and Carl
    > Kugler (thank
    > you all), an improved conformance section for the IPP URL Scheme spec:
    >
    > 5. Conformance Requirements
    >
    >
    > 5.1. Conformance Requirements for IPP Clients
    >
    > IPP Clients that conform to this specification:
    >
    > a) MUST send IPP URLs (e.g., in the "printer-uri"
    > operation attribute
    > in 'Print-Job') that conform to the ABNF specified in
    > section 4.4
    > of this document;
    >
    > b) MUST send IPP operations via the port specified in the
    > IPP URL (if
    > present) or otherwise via IANA assigned well-known port 631;
    >
    > c) MUST convert IPP URLs to their corresponding HTTP URL forms
    > according to the rules in section 5 'IPP URL Scheme' in
    > [RFC-2910];
    >
    > d) SHOULD interoperate with IPP/1.0 Printers according to the rules
    > in section 9 'Interoperability with IPP/1.0 Implementations' and
    > section 9.2 'Security and URL Schemes' in [RFC-2910].
    >
    >
    > 5.2. Conformance Requirements for IPP Printers
    >
    > IPP Printers that conform to this specification:
    >
    > a) SHOULD reject received IPP URLs in "application/ipp" request
    > bodies (e.g., in the "printer-uri" attribute in a 'Print-Job'
    > request) that do not conform to the ABNF for IPP URLs
    > specified in
    > section 4.4 of this document;
    >
    > b) SHOULD return IPP URLs in "application/ipp" response
    > bodies (e.g.,
    > in the "job-uri" attribute in a 'Print-Job' response) that do
    > conform to the ABNF for IPP URLs specified in section
    > 4.4 of this
    > document;
    >
    > c) MUST listen for IPP operations on IANA-assigned well-known port
    > 631, unless explicitly configured by system
    > administrators or site
    > policies;
    >
    > d) SHOULD NOT listen for IPP operations on any other port, unless
    > explicitly configured by system administrators or site
    > policies;
    >
    > e) SHOULD interoperate with IPP/1.0 Clients according to
    > the rules in
    > section 9 'Interoperability with IPP/1.0 Implementations' and
    > section 9.2 'Security and URL Schemes' in [RFC-2910].
    >
    > Comments?
    >
    > Cheers,
    > - Ira McDonald, consulting architect at Sharp and Xerox
    > High North Inc
    >
    > PS - I've also greatly simplified the ABNF to _one_line_ taken from
    > HTTP/1.1 [RFC-2616] and clarified that the 'ipp:' URL scheme can only
    > be used for the [RFC-2910] mapping of the IPP model over HTTP.
    >



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