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Frequently asked Questions (FAQ) about the Internet Printing Protocol (IPP)
project - Date: March 4, 1997
Q: What is the history of the IPP project?
A: In the summer of 1996, Novell approached a number of companies to find
out if they were interested to participate in a printing protocol project
for the Internet. Xerox and others expressed some interest and suggested
that the first step would be to develop a draft text and decide how to
initiate the project. As result, a first draft document was developed in
cooperation between Novell and Xerox. At this stage, the project was
known as Lightweight Document Printing Application (LDPA). In a parallel
effort, IBM had started working on a proposal for Internet printing using
Web technology, under the name of HyperText Printing Protocol (HTPP). It
was also known that Microsoft/HP/Lexmark had started work on a proprietary
solution for a new generation of print service for Windows NT. QMS and
Adobe had also announced products in the same vain.
In parallel to the writing of initial draft texts, it was investigated how
to start up the public standardization project. It was clear from the
beginning that the initiators wanted the project to become an acknowledged
project with the Internet Engineering Task Force (IETF), but first needed
to get together a forum of experts before suggesting it to the IETF. The
choice was to start the activity in the Printer Working Group (PWG), a
group of people with representation from printer and print server vendors,
which had previously developed the IETF Printer MIB specification. After
initial discussions in a couple of earlier meetings, the PWG started the
IPP project in November 1996. Carl-Uno Manros from Xerox was chosen as the
project chair and Scott Isaacson from Novell as the main editor. Steve
Zilles from Adobe was later proposed as the IETF co-chair. After some
discussion, it was decided to pool the earlier efforts from Novell/Xerox
and IBM into what was then named the Internet Printing Protocol (IPP)
project. Some 20 companies involved with printers and/or print servers
confirmed that hey were interested in participating. After negotiation
with the Application Area Directors in the IETF, it was decided to hold a
birds-of-a-feather (BOF) session for IPP in the December 1996 meeting of
the IETF. The outcome of that meeting confirmed that there was widespread
interest in developing a printing protocol for the Internet.
---Q: What is the current Status in the IETF?
A: Several draft versions of the Working Group Charter have been given to the IETF Area Directors for Applications for review and approval. The latest draft is currently reviewed by the IESG for formal approval. It is expected that the group will be formally chartered in time for the IETF Meeting in Memphis, TN, April 7 - 11, 1997.
---Q: What is the scope of the IPP project?
A: The latest version of the IETF WG Charter text, describes the project (IPP version 1) as:
There is currently no universal standard for printing. Several protocols are in use, but each has limited applicability and none can be considered the prevalent one. This means that printer vendors have to implement and support a number of different protocols and protocol variants. There is a need to define a protocol which can cover the most common situations for printing on the Internet.
The goal of this working group is to develop requirements for Internet Printing and to describe a model and semantics for Internet Printing.
The further goal is to define a new application level Internet Printing Protocol for the following core functions:
- for a user to find out about a printer's capabilities - for a user to submit print jobs to a printer - for a user to find out the status of a printer or a print job - for a user to cancel a previously submitted job
The Internet Printing Protocol is a client-server type protocol which should allow the server side to be either a separate print server or a printer with embedded networking capabilities. The focus of this effort is optimized for printers, but might be applied to other output devices. These are outside the scope of this working group.
The working group will also define a set of directory attributes that can be used to ease finding printers on the network.
---Q: If this is version 1 of IPP, what is intended for inclusion in future versions?
A: Other capabilities that will be examined for future versions include:
- features needed by administrators and operators of a printing system - security features for authentication, authorization, and policies - notifications from the server to the client - accounting
---Q: What subjects are out-of-scope for the IPP project?
A: Subjects currently out of scope for this working group are:
- property rights - fax input - scanning
---Q: Will this effort be coordinated with printing standards efforts in other groups?
A: The IPP working group will strive to coordinate its activities with other printing-related standards bodies, without the need to be strictly bound by their standards definitions. These groups are:
- ISO/IEC JTC 1/SC 18/WG 4 on Document Printing Application (ISO/IEC 10175 parts 1 - 3) - The Object Management Group (OMG) on OMG Printing Facility (in= development) - IEEE (POSIX System Administration - Part 4: Printing Interfaces) - X/Open (Printing Systems Interoperability Specification) - but it looks like this spec. will be dropped - The Printer Working Group
---Q: There is already an Internet printing standard defined in RFC 1179. - Why are you developing a new one?
A: If you look a little more carefully at RFC 1179 you will find that it is just an informational RFC, intended to document a commonly used, but proprietary set of functionality for Unix machines. It was never intended for the Internet Standards Track. Many vendors have used the RFC 1179 as a starting point for implementations, but have then added their own proprietary extensions to it up to a point where there is now no more meaningful to talk about RFC 1179 as even a "de-facto" standard. All active participants in the project have declared that they consider RFC 1179 to be useless as the starting point for IPP.
---Q: What is the Document Printing Application (DPA)?
A: DPA is an ISO standard for printing (ISO/IEC 10175) that has been worked on for a number of years, and which was finally published in 1996. DPA has a lot of printing functionality defined, probably more than anybody will ever implement in a product. Even if DPA can be seen as a bit of an overkill, it does provide a lot of useful input to any project that works on printing. Several experts in the IPP project have been active in the specification of DPA and can leverage experience from that project. Semantically, IPP can be seen as lightweight version of the functionality covered in DPA, with some new features thrown in, but the syntax, protocol stack etc. will be different in the Internet environment.
-- =20 Q: What documents are the IPP project planning to develop?
A: The currently proposed texts are:
=B7 Internet Printing Protocol: Requirements and Scenarios (Informational) =B7 Internet Printing Protoco/1.0: Model and Semantics (Standards Track) =B7 Internet Printing Protoco/1.0: Protocol (Standards Track) =B7 Internet Printing Protoco/1.0: Directory Schema (Standards Track)
---Q: How can I get involved in the IPP project?
A: You can get information and participate over the Internet in the following ways:
General Discussion DL: ipp@pwg.org To Subscribe to the DL: ipp-request@pwg.org Archive: ftp://ftp.pwg.org/pub/pwg/ipp/ Web-site: http://www.pwg.org/ipp
In addition, the PWG organizes face-to-face meetings in the US about once a month, and also holds frequent telephone conferences. Announcements about these are given over the DL. If you are new to the project, the best starting point is our Web pages, which contain pointers to everything else you need to know.
---Q: How is the work in the IPP project currently organized?
A: The formalities in the IETF have not held up the actual work in the PWG. One-day meetings were held in January and February 1997 with an increasing number of participants. The latest meeting had 45 people attending, representing most of the American and Japanese printer and print server vendors and also included representatives from Microsoft and Netscape. In addition to the face-to-face meetings, weekly phone conferences and intensive discussions over email are held. The project has established six subgroups, which work on different aspects of the specifications, the first four of which are expected to produce an RFC document as output:
- REQ - Requirements & Scenarios - MOD - Model & Semantics - DIR - Directory support - PRO - Protocol - SEC - Security - TES - Prototyping & Testing
Four companies so far have set up prototyping teams: Canon, IBM, Novell and Xerox, other are expected to follow.
---Q: What is the current schedule for the IPP project?
A: The PWG had an initial schedule to have a set of specifications stable within 6 months (=3D May 1997), which might turn out to be a bit optimistic. Current expectations are that the group will have the specifications for Requirements, and for Model & Semantics, ready by mid-year followed by the Protocol and the Directory Support documents a few months later. A major difference compared to some earlier standardization projects, is that we now prototype as we go along to ensure the functionality of the specifications and try to avoid inefficient solutions. Internet-Drafts of the first two documents for review in the IETF are planned for end of March, 1997.
---Carl-Uno Manros - IPP project chair - March 4, 1997
--- Carl-Uno Manros Principal Engineer - Advanced Printing Standards - Xerox Corporation 701 S. Aviation Blvd., El Segundo, CA, M/S: ESAE-231 Phone +1-310-333 8273, Fax +1-310-333 5514 Email: manros@cp10.es.xerox.com