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<BODY style="MARGIN: 4px 4px 1px; FONT: 10pt Tahoma">I will be unable to attend the meeting tomorrow. But just to give my two cents worth, I would be ok with option 1 or 2<BR><BR>>>> "McDonald, Ira" <firstname.lastname@example.org> 7/19/2006 12:43 PM >>><BR>Hi folks, Wednesday (19 July 2006)<BR><BR>As background for tomorrow's teleconference reviewing the first draft of<BR>PWG IPP Printer State Reasons Extensions, below is a summary of the four<BR>available methods in IPP to represent correlated elements (e.g., various<BR>columnar object values from a specific 'prtAlertTable' entry).<BR><BR>Note that the IPP Printer State Reasons Extensions MUST be practical for<BR>easy addition to ALL of the existing IPP implementations, or else such a<BR>standardized approach is not cost effective (to specify or implement).<BR><BR>Method (1) below was chosen for our first draft IPP PSX spec because it<BR>requires NO new IPP atrributes (uses existing "printer-state-reasons"<BR>and "printer-state-message") and thus is immediately available in all<BR>existing IPP client implementations - this is very important to Sharp.<BR><BR>Cheers,<BR>- Ira (co-editor of PWG IPP Printer State Reasons Extensions)<BR><BR><BR>Ira McDonald (Musician / Software Architect)<BR>Blue Roof Music / High North Inc<BR>PO Box 221 Grand Marais, MI 49839<BR>phone: +1-906-494-2434<BR>email: email@example.com<BR><BR>------------------------------------------------------------------------<BR><BR>(1) Method: Structured encoding in a single string<BR><BR> Example: From IPP Printer Installation Extension<BR> (ftp://ftp.pwg.org/pub/pwg/ipp/new_DRV/<BR> &!
sp; draft-ietf-ipp-install-04.txt)<BR> "client-print-support-files-supported (1setOf<BR> octetString(MAX))"<BR><BR> Remarks: In practice, localized elements can't be supported with<BR> reliable interoperability - but this has no importance for<BR> the current IPP PSX spec.<BR><BR><BR>(2) Method: Parallel ordered multi-valued attributes<BR><BR> Example: From IPP/1.1 Model and Semantics<BR> (ftp://ftp.isi.edu/in-notes/<BR> rfc2911.txt)<BR> "printer-uri-supported (1setOf uri)"<BR> "uri-authentication-supported (1setOf type2 keyword)"<BR> "uri-security-supported (1setOf type2 keyword)<BR><BR> Remarks: The '1setOf X' datatype (section 4.1.16 of RFC2911) is<BR> fragile for interoperability, because IPP/1.1 states:<BR><BR> "Sets are normally unordered. However each attribute<BR> description of this type may specify that the values<BR> MUST be in a certain order for that attribute."<BR><BR> &nbs!
In practice, this means that a generic IPP parser MUST NOT<BR> be order-preserving, thus the inherent fragility.<BR><BR><BR>(3) Method: Members in an IPP 'collection' attribute (per RFC 3382)<BR><BR> Example: From IPP Production Printing Attributes - Set1<BR> (ftp://ftp.pwg.org/pub/pwg/candidates/<BR> cs-ippprodprint10-20010212-5100.3.pdf)<BR> "media-col (collection)"<BR> "media-type (type3 keyword | name(MAX))"<BR> "media-info (text(255))"<BR><BR> Remarks: The 'collection' datatype is NOT a base IPP/1.1 type, but<BR> rather an extension - which has NOT been demonstrated to be<BR> interoperable across various IPP parser implementations.<BR> The 'collection' datatype is NOT supported in the majority<BR> of existing IPP/1.1 implementations from various vendors.<BR> There are no known implementations of 'collection' datatype<BR> in IPP/1.0 implementations - many network printers ONLY<BR> support the protocol/datatypes in IPP/1.0 (RFC 2!
).<BR><BR><BR>(4) Method: Attributes in a new first-class IPP object<BR><BR> Example: From IPP Document Object<BR> (ftp://ftp.pwg.org/pub/pwg/candidates/<BR> cs-ippdocobject10-20031031-5100.5.pdf)<BR> "document-charset (charset)"<BR> "document-format (mimeMediaType)"<BR><BR> Remarks: The Document object is the ONLY object that has ever been<BR> defined to extend IPP/1.1 - there has never been an IPP<BR> bakeoff to demonstrate interoperability of this object.<BR> There was a strong resistance among former IPP editors to<BR> the definition of new first-class IPP objects - which was<BR> the specific justification for the introduction of the<BR> 'collection' datatype - this is not a practical approach.<BR><BR>------------------------------------------------------------------------<BR><BR>-- <BR>No virus found in this outgoing message.<BR>Checked by AVG Free Edition.<BR>Version: 7.1.394 / Virus Database: 268.10.1/391 - Release Date: 7/18/2006<BR><BR></BODY></HTML>