Network working group Graham Klyne (editor) Internet draft Content Technologies Category: Work-in-progress Richard Shockey Shockey Consulting LLC 22 October 1999 Expires: April 2000 Additional Goals for Quality Document Transfer Status of this memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC 2026. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet- Drafts as reference material or to cite them other than as "work in progress." To view the list Internet-Draft Shadow Directories, see http://www.ietf.org/shadow.html. Copyright Notice Copyright (C) The Internet Society 1999. All Rights Reserved. Abstract This document sets out some goals beyond those in "Terminology and Goals for Internet Fax" [4] for a service to perform fax and high quality document transmission across the Internet. Internet fax [1,2] defines a way to send fax data over the Internet using e-mail. But there is a clear desire for an application that more closely emulates the operational characteristics of traditional fax [3]. Klyne & Shockey Work-in-progress [Page 1] Internet Draft Additional Goals for Quality Document Transfer 22 October 1999 Table of contents 1. Introduction ............................................2 1.1 Organization of this document 3 1.2 Document conventions 3 1.3 Discussion of this document 3 2. Timeliness characteristics ..............................4 3. Goals for High Quality Document Distribution ............5 3.1 Timely delivery 6 3.2 Proof of delivery/receipt 6 3.3 Date and time information 7 3.4 Quality of output 7 3.5 Sender and receiver identity exchange 7 3.6 Cover page 8 3.7 Interworking with other services 8 4. Other considerations ....................................8 4.1 Third party operation 9 5. Internationalization considerations .....................9 6. Security considerations .................................9 7. Full copyright statement ................................10 8. Acknowledgements ........................................10 9. References ..............................................10 10. Authors' addresses .....................................12 Appendix A: Revision history ...............................13 1. Introduction The transmission and reception of renderable documents (i.e. in a form that can control their final rendering) is an essential global communications service. Several protocols and services have been developed over the years to facilitate document transmission, including the GSTN Fax service, ITU-T T.30 [3]. Within the IETF several protocols have been developed that can be used for document transmission, including Internet fax [1,2] (using e-mail protocols) and the Internet Print Protocol [5] (using elements from HTTP). But there are indications that users expect a service that more closely emulates the operational characteristics of traditional fax [3]. This document sets out some goals for such a service. Klyne & Shockey Work-in-progress [Page 2] Internet Draft Additional Goals for Quality Document Transfer 22 October 1999 1.1 Organization of this document "Terminology and Goals for Internet Fax" [4] is used as a baseline for these goals; this memo further expands on some issues that characterize the current practice of facsimile transmission. These features are intended to facilitate the use of quality document transfer in compliance with the legal as well as general custom and practice surrounding document transmission by facsimile. Section 2 discusses the operational modes for Internet fax, and how they might relate to user perceptions of timeliness of message delivery. Section 3 describes the goals for quality document transfer. It starts with a brief listing of all the goals, then proceeds to explain in more detail those that are not described elsewhere. Section 4 discusses some additional considerations beyond obvious application goals. 1.2 Document conventions This memo uses the annotations described in "Terminology and Goals for Internet Fax" [4] to indicate levels of desirability for a quality document transfer protocol: {1} there is general agreement that this is a critical characteristic of any definition of a quality document transfer protocol. {2} most believe that this is an important characteristic of a quality document transfer protocol. {3} there is general belief that this is a useful feature of a quality document transfer protocol, but that other factors might override; a definition that does not provide this element is acceptable. NOTE: Comments like this provide additional nonessential information about the rationale behind this document, and may help those who wish to understand the ideas in greater depth. 1.3 Discussion of this document Please send comments regarding this document to: ifx@pwg.org Klyne & Shockey Work-in-progress [Page 3] Internet Draft Additional Goals for Quality Document Transfer 22 October 1999 To subscribe to this list, send a message with the body 'subscribe ifx' to 'Majordomo@pwg.org'. To see what has gone on before you subscribed, please see the mailing list archive at: http://www.pwg.org/hypermail/ifx 2. Timeliness characteristics RFC 2542 [4], section 2.5, discusses three operational modes for Internet fax. These describe different ways of performing message transfer that typically exhibit different behaviours: o "Store and forward" is typically associated with delivery times that may vary between minutes and hours, or even days (e.g. ordinary Internet mail.) o "Session" relates to a kind of "while-you-wait" service, where the length of time one waits may depend on the number of other users of the same network resources (e.g. accessing a web page). The intent of "session" mode described in RFC 2542 is to provide a timely delivery without being constrained by the kind of rigid protocol timing constraints that are normal when using a circuit based protocol like T.30.) o "Real time" means that delivery is completed within some defined maximum time, or the process is deemed to have failed. Traditional Group 3 facsimile is a real time service in this sense. True real time behaviour can be difficult to achieve reliably in the global Internet. RFC 2542 defines "Real-time Internet Fax" to mean a service that allows two standard Group 3 fax terminals using T.30 protocols to communicate via the Internet. This specifically requires that the various T.30 signals and responses are completed within quite short periods of time. For the purposes of this memo, these ideas are connoted by the characteristic of timely delivery: o "Timely delivery" means that a document is delivered, and any confirmation is returned, reliably and within a predictable period of time that is short enough to be useful for the purposes of routine communications. Klyne & Shockey Work-in-progress [Page 4] Internet Draft Additional Goals for Quality Document Transfer 22 October 1999 3. Goals for High Quality Document Distribution [[[It's not clear to me whether we want to separate specification requirements from "operational goals" and "functional goals", as in RFC2542. I think we should see what material we generate for this.]]] [[[What we probably do need to do is separate these into goals that must be adressed by a protocol specification, and goals that should be addressed by an implementation. Non-protocol goals could be migrated to section 4.]]] This section recalls and expands upon the goals described in RFC 2542 [4], sections 4 and 5. The goals are: o {1} timely delivery (section 3.1 below, and RFC 2542 section 4.4) o {1} proof of delivery/receipt (section 3.2 below, and RFC 2542 section 4.3) o {1} date and time information (Section 3.3 below, and RFC 2542 section 4.10) o {1} data format support (RFC 2542 section 5.1) o {1} quality of output (Section 3.4 below) o {1} capabilities exchange (RFC 2542 sections 4.5 and 5,5) o {1} addressing support (RFC 2542, section 5.3) o {2} legal identity exchange (Section 3.5 below) o {2} legal issues (RFC 2542 section 4.10) o {2} cover pages (Section 3.6 below) o {1} security (RFC 2542 section 4.7) o {2} interworking with other services (Section 3.7 below, and RFC 2542 section 4.2) o {2} High Quality Document Transfer should be reasonable easy to implement (RFC 2542, section 4.6) o {1} a Quality Document Transfer protocol must operate reliably in the global Internet. (See RFC 2542, section 4.8.) Klyne & Shockey Work-in-progress [Page 5] Internet Draft Additional Goals for Quality Document Transfer 22 October 1999 o {3} it is desirable that a Quality Document Transfer protocol makes use of existing infrastructure. (See RFC 2542, sections 4.2 and 5.2) o {3} features shared with other messaging applications. (See RFC 2542, sections 2.4.3, 2.4.4) o {3} it is desirable that a Quality Document Transfer protocol support and facilitate universal messaging systems (RFC 2542, section 2.4.5 [4]) 3.1 Timely delivery (See RFC 2542, section 4.4. The timeliness goal for a Quality Document Transfer protocol is stonger.) A Quality Document Transfer protocol must provide delivery of a document immediately, or very soon after it is transmitted. That is, within a period of time that a human user might reasonably wait for delivery to be completed (e.g. less than a minute). 3.2 Proof of delivery/receipt (See RFC 2542, section 4.3. The reporting goals are elaborated here; these are mostly implementaton requirements but may have some bearing on the protocol design.) Detailed progress reports and transaction logs have become standard end user requirements for a facsimile service in order to document the receipt and confirmation of facsimile delivery. Current e-mail based Internet fax protocols do not fully satisfy the confirmation requirements for all current users of traditional facsimile. Reports from a Quality Document Transfer terminal: o Must note status (SUCCESS, or FAILURE and information about the cause of failure that might be needed to achieve a successful transmission) o Must note date and time of all attempts (log files recorded at each end by client and server locally) o May note the duration of the transaction o May note the number of document pages transferred o Should indicate the identity of sender and recipient. Klyne & Shockey Work-in-progress [Page 6] Internet Draft Additional Goals for Quality Document Transfer 22 October 1999 3.3 Date and time information (See RFC 2542, section 4.10. This section expands on the indicated legal requirement for date and time of transmission to be indicated.) Closely associated with the need for transaction receipt and notification is the legal requirement (see "Legal issues") that at least the first page of a facsimile contain the time and date of transmission and that information be included in any facsimile service record. Facsimile terminal devices all have internal clock devices for recording the time/date of transactions. Actual time information is not exchanged "on the wire". Each device notes when it sends and receives documents and logs those transactions appropriately. All Internet fax transactions note time/date information in the e-mail header information. Examples of transaction information that may be useful to record include: - time of transmission by sender - time of reception by receiver - time that rendering (e.g. printing) is completed 3.4 Quality of output It is a fundamental goal of High Quality Document Transfer that not only is the information content of a document transferred, but also that high presentation quality can be achieved. Received documents should be capable of presentation that allows them to be used directly in the same ways that a locally prepared document might be used. (Contrast with traditional facsimile, which typicaly does not provide an image one would choose to use directly in an internal report.) 3.5 Sender and receiver identity exchange (See RFC 2542, section 4.10. This section expands on the indicated requirement for the identity of the sender to be indicated.) Some jurisdictions impose a requirement for a fax machine to disclose its identity under certain circumstances. This disclosure is achieved for traditional facsimile through local configuration of the fax terminal, and the exchange of T.30 CSID frames between terminal devices. Klyne & Shockey Work-in-progress [Page 7] Internet Draft Additional Goals for Quality Document Transfer 22 October 1999 Internet fax uses e-mail header information to identify the sender to the recipient. A Quality Document Transfer protocol should define a mechanism for achieving a full exchange of identity between a sender and receiver. 3.6 Cover page Closely associated with the legal issues are the formats and requirements for cover pages. A Quality Document Transfer protocol should provide a mechanism to include cover page information that conforms to the legal or general custom and practice applied to facsimile services, when such information is not already part of the document being sent. To satisfy legal requirements for Facsimile transmission cover pages: o Must contain identification of Sender: o Should contain identification of Recipient: o Must contain time/Date of Transmission: o May contain number of pages in Transmission: o May contain an area for short comments: Workstation software, when operating in a facsimile service mode, should offer cover page generation options and may offer other features, as deemed appropriate. If possible, cover page information should be distinguishable from message payload data (e.g. see the cover page proposal for Internet fax [21]). 3.7 Interworking with other services (See RFC 2542, section 4.2 and section 2.) It is likely that a High Quality Document Transfer system will be required to gateway to another document distribution service; this may require conversion of the available document data to/from a format used by the other service. Choice of baseline data formats and capabilities will ideally be compatible with other applications with which systems may be required to interwork. 4. Other considerations This section discusses some considerations for High Quality Document Distribution that do not create readily identifiable application goals. Klyne & Shockey Work-in-progress [Page 8] Internet Draft Additional Goals for Quality Document Transfer 22 October 1999 4.1 Third party operation In some environments, it may be desirable to hand off delivery of a document to some third party and report back (a) the fact that the hand-off has occurred, and (b) subsequent indication from the third party that delivery has indeed been effected. An example of this kind of scenario would be a service that received documents electronically, printed them, then obtains a signature when delivering the physical document. 5. Internationalization considerations Quality document transfer must be regarded as a global service, and any specification must have consideration for: o {1} transferring documents whose contents are expressed in a variety of national symbol sets. o {2} transferring documents whose contents are expressed in a variety of national languages (in some cases, the language of the content may be important to its rendering; e.g. text-to-speech processing). o {3} document transfer destination adressess that may be expressed in a variety of national symbol sets (e.g. the names of a person to whom a document is addressed). NOTE: There are a number of documents covering internationalization issues: RFC 2130 [6], RFC 2277 [7] and others [8]. 6. Security considerations Security goals and considerations are addressed by RFC 2542. Klyne & Shockey Work-in-progress [Page 9] Internet Draft Additional Goals for Quality Document Transfer 22 October 1999 7. Full copyright statement Copyright (C) The Internet Society 1999. All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 8. Acknowledgements The authors would like to thank the following people for providing comments on this document: Larry Masinter. [[[TBD]]] 9. References [1] RFC 2305, "A Simple Mode of Facsimile Using Internet Mail" K. Toyoda H. Ohno J. Murai, WIDE Project D. Wing, Cisco Systems March 1998. [2] RFC 2532, "Extended Facsimile Using Internet Mail" Larry Masinter, Xerox Corporation Dan Wing, Cisco Systems September 1998. Klyne & Shockey Work-in-progress [Page 10] Internet Draft Additional Goals for Quality Document Transfer 22 October 1999 [3] "Procedures for document facsimile transmission in the general switched telephone network" ITU-T Recommendation T.30 (1996) International Telecommunications Union July 1996 [4] RFC 2542, "Terminology and Goals for Internet Fax" Larry Masinter, Xerox Corporation September 1998 [5] IPP [6] RFC 2130, "The Report of the IAB Character Set Workshop" C. Weider, Microsoft C. Preston, Preston & Lynch K. Simonsen, DKUUG H. Alvestrand, UNINETT R. Atkinson, Cisco Systems M. Crispin, University of Washington P. Svanberg, KTH April 1997. [7] RFC 2277, "IETF Policy on Character Sets and Languages" H. Alvestrand, UNINETT January 1998. [8] <<>> [9] T.4 [10] T.6 [11] TIFF-FX [12] E.164 [13] SMTP [14] RFC822 [15] MDN/DSN reporting extensions [16] RFC 2533 [17] RFC 2531 [18] T.30 mapping document [19] RFC 1891 (DSN) Klyne & Shockey Work-in-progress [Page 11] Internet Draft Additional Goals for Quality Document Transfer 22 October 1999 [20] RFC 2298 (MDN) [21] Cover page proposal [22] RFC 867 (Daytime) [23] RFC 868 (Time) [24] RFC 1305 (NTP) [25] RFC 2030 (SNTP) 10. Authors' addresses Graham Klyne (editor) Content Technologies Ltd. 1220 Parkview, Arlington Business Park Theale Reading, RG7 4SA United Kingdom. Telephone: +44 118 930 1300 Facsimile: +44 118 930 1301 E-mail: GK@ACM.ORG Richard Shockey Shockey Consulting LLC 8045 Big Bend Blvd Suite 100 St. Louis, MO 63119 Telephone: +1 314 918 9020 Facsimile: +1 314 918 9015 E-mail/IFAX: rshockey@ix.netcom.com Klyne & Shockey Work-in-progress [Page 12] Internet Draft Additional Goals for Quality Document Transfer 22 October 1999 Appendix A: Revision history [[[Please remove this section on publication]]] 00a 23-Jul-1999 Initial draft, based on an earlier document by Richard Shockey. 00b 08-Sep-1999 Incorporate Richard's review comments. 01a 04-Oct-1999 Align goals more closely with RFC 2542; remove some text that duplicates RFC 2542. 01b 18-Oct-1999 Re-work introductory text slightly. 02a 22-Oct-1999 Extensive editing following early review comments, particularly to improve the alignment of ideas and text with RFC 2542. 02b 22-Oct-1999 Further cut back the goals section; add new section for "Other considerations". TODO: o Finalize references o Separate "operational" and "functional" goals? (section 4 intro) o Separate confirmation of receipt/proof of delivery? Klyne & Shockey Work-in-progress [Page 13]