Fax Working Group Dan Wing Internet Draft Cisco Systems August 7, 1998 Expires January 1999 draft-ietf-fax-t30-capabilities-00.txt Expressing Fax Capabilities in Internet Protocols Status of this memo This document is an Internet-Draft. 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 entire list of current Internet-Drafts, please check the "1id-abstracts.txt" listing contained in the Internet-Drafts Shadow Directories on ftp.is.co.za (Africa), ftp.nordu.net (Northern Europe), ftp.nis.garr.it (Southern Europe), munnari.oz.au (Pacific Rim), ftp.ietf.org (US East Coast), or ftp.isi.edu (US West Coast). Copyright Notice Copyright (C) The Internet Society (1998). All Rights Reserved. 1. Abstract This document describes how the DIS Standard Capabilities and Non-Standard Capabilities (NSF) of [T.30] can be expressed using the format described by the IETF Content Negotiation Working Group [MEDIA-FEATURES, FEATURE-ALGEBRA, FEATURE-REG]. The format described in this document, and the format described in [FEATURE-ALGEBRA] is intended to be usable in many Internet protocols and by a variety of methods. The specific methods are not described by this document. 2. Introduction To exchange documents between a sender and recipient it is important to know the display or print capabilities of the recipient. The fax protocol [T.30] has a long-established method of exchanging capabilities. The fax protocol requires a realtime connection between the sender and receiver, and is not designed to be cached by the sender or to be shared with multiple senders. Additionally, the [T.30] capabilities exchange describes many data link layer specific information which is not applicable to an Internet application layer program. On the Internet, it is not expected that document exchange devices and software such as MUAs, printers, word processors, or PostScript will have knowledge of the fax protocol [T.30], except in the case of Internet Fax (IFax) devices themselves or MultiFunction Periphials (MFPs). Non-fax devices and software which creates, manipulates, or prints images are more likely to use capability expressions which are more portable across multiple devices than the capability expressions of [T.30]. The portion of the T.30 protocol used to indicate the capabilities of the recipient is the DIS Standard Capabilities (section 5.3.6.2.1 of [T.30]) and the Non-Standard Capabilities (NSF, section 5.3.6.2.7 of [T.30]) which is used for vendor- specific extensions. This draft is being discussed on the "ietf-fax" mailing list. To subscribe, send a message to: ietf-fax-request@imc.org with the line: subscribe in the body of the message. Archives are available from . 3. Mapping DIS The following DIS bits and their function are described in [T.30] and mapped using the descriptions in the following sections. The following sections use ABNF [RFC2234] to describe the syntax. DIS bit number T.30 use Section -------------- -------- ------- 1 Reserved 2 Reserved 3 Reserved 4 Reserved 5 Reserved 6 V.8 capabilities 3.1 7 256/64 octets preferred 3.1 8 Reserved 9 Polling 3.2 10 Receiver fax operation 3.1 11-14 Data signalling rate 3.1 15 Paper size 3.3 16 2D coding capability 3.1 17-18 Scan line width 3.3 19-20 Page height 3.3 21-23 Scan line receive rate 3.1 24 Extend field 3.1 25 Reserved 26 Uncompressed mode 3.11 27 Error correction mode 3.1 28 Must be 0 3.1 29 Reserved 30 Reserved 31 T.6 coding 3.4 32 Extend field 3.1 33-39 Reserved 40 Extend field 3.1 41 Paper size 3.3 42 ? ? 43 Paper size (inch/metric) 3.3 44 Inch resolution preferred 3.5 45 Metric resolution preferred 3.5 46 Scan line receive rate 3.1 47 Selective polling 3.2 48 Extend field 3.1 49 Subaddress 3.6 50 Password 3.10 51 Ready to xmit (polling) 3.2 52 Reserved 53-55 Binary File Transfer 3.7 56 Extend field 3.1 57 Binary File Transfer 3.7 58 Reserved 59 Ready for polling 3.2 60 Character mode ? 61 Reserved 62 Mixed mode (color) 3.8 63 Reserved 64 Extend field 3.1 65 T.505 ? 66 Digital network capable 3.1 67 Duplex/half-duplex 3.1 68 JPEG encoding 3.9 69 Full color mode 3.8 70 Must be 0 3.1 71 8 or 12 bits/pel/component 3.8 72 Extend field 3.1 73 Color subsampling 3.8 74 Custom illuminant 3.8 75 Custom gamut range 3.8 76-77 N. American letter/legal 3.3 78 T.85 capability ? 79 T.85 L0 capability ? 80 Extend field 3.1. Not Applicable to Content Negotiation This item is not applicable to content negotiation. For example, this item may refer to data rate of the modem, if error correction mode is enabled, or the fastest receive rate supported. As only a file describing the data is transmitted between the sender and receiver [TIFF], the only information necessary is what data will be understood by the recipient, not other information which is performed by the actual fax offramp. 3.2. Polling With SMTP polling is acheived with the TURN, ETRN, and ATRN commands [ref]. With HTTP polling is acheived with GET [ref]. With FTP polling is acheived with RETR. Thus, information about a remote machine's ability to have messages polled is not useful to use over the Internet. 3.3. Paper Size Paper size is expressed as: papersize = "Papersize" "=" token token = "na-letter" / "iso-a4" / "iso-b4" / "iso-a3" / "na-legal" 3.4. Group 4 Facsimile ? What do we want to say about group 4 3.5. Inch versus Metric resolution The algebra of [FEATURE-ALG] handles both metric- and inch- based measurements. 3.6. Subaddressing Subaddressing is handled by the addressing format described in [RFC2303, RFC2304], and is ignored by the fax offramp if the legacy fax doesn't advertise support for subaddresses. 3.7. Binary File Transfer Binary File Transfer is acheived on the Internet using FTP, HTTP, and MIME messages in SMTP. 3.8. Color Transmission ? What do we want to say about color 3.9. JPEG Encoding For Internet Fax we are only supporting TIFF->FAX and FAX->TIFF. 3.10. Password The password, used to authenticate the recipient, is equivalent to the password necessary to retreive POP (or IMAP) messages from a POP (or IMAP) server. Similar authentication is available with SMTP with [AUTH], and with the password with FTP. With SMTP, stronger authentication is available with [SMIME] or [PGP-MIME] and [SMTP-TLS], and with HTTP with [HTTP-SSL]. The fax offramp may wish to use the legacy machine's supplied password to authenticate the recipient. This could be done by comparing a special field in the recipient's email address (if using SMTP), such as "/T30PASSWORD=8924". 3.11. Compression XXX - we need to determine if the offramp will be responsible for changing compressions, or if this will be something that is expressed as one of the CONNEG features. 4. Mapping Non-Standard Features (NSF) Many fax manufacturers support features that are not part of the [T.30] specification. These features allow better compression, higher resolution, or provide other similar value- add features. Each fax manufacturer which wishes to provide such a feature should map the feature to the algebra described in [FEATURE-ALG]. This allows the feature to be expressed to senders using the same mechanism as described in section 3 of this document. 5. Security Considerations ? 5. Acknowledgments XXX 7. References [EIFAX] L. Masinter, D. Wing, "Extended Facsimile Using Internet Mail", Internet Draft, Work in Progress, draft-ietf-fax-eifax-XX.txt [FAX-REQ] L. Masinter, "Requirements for Internet FAX", Internet Draft, Work in Progress, draft-ietf-fax-requirements-XX.txt. [FEATURE-ALGEBRA] G. Klyne, "An algebra for describing media feature sets", Internet Draft, Work in Progress, draft-ietf-conneg-feature-algebra-XX.txt. [FEATURE-REG] K. Holtman, A. Mutz, T. Hardie, "Content Feature Tag Registration Procedure", Internet Draft, Work in Progress, draft-ietf-conneg-feature-reg-XX.txt. [MEDIA-FEATURES] L. Masinter, K. Holtman, D. Wing, "Media Features for Display, Print, and Fax", Internet Draft, Work in Progress, draft-ietf-conneg-media-features-XX.txt. [RFC2303] C. Allocchio, "Minimal PSTN address format in Internet Mail", RFC 1303, March 1998. [RFC2304] C. Allocchio, "Minimal FAX address format in Internet Mail", RFC 2304, March 1998. [RFC2305] K. Toyoda, H. Ohno, J. Murai, D. Wing, "A Simple Mode of Facsimile Using Internet Mail", RFC 2305, March 1998. [RFC2234] D. Crocker, P. Overell, "Augmented BNF for Syntax Specifications: ABNF", RFC 2234, November 1997. [T.30] ITU-T (CCITT), "Procedures for Document Facsimile Transmission in the General Switched Telephone Network", ITU-T (CCITT), Recommendation T.30, July, 1996. 9. Copyright Copyright (C) The Internet Society 1998. All Rights Reserved. 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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. 10. Author's Address Dan Wing Cisco Systems, Inc. 101 Cooper Street Santa Cruz, CA 95060 USA Phone: +1 408 457 5200 Fax: +1 408 457 5208 EMail: dwing@cisco.com