Fax Working Group Dan Wing Internet Draft Cisco Systems June 8, 1998 Larry Masinter Expires November 1998 Xerox PARC draft-ietf-fax-dsn-extensions-01.txt Extensions to Delivery Status Notifications for Fax 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 The Internet fax specification [RFC2305] describes a simple mode of operation for fax over SMTP. [EIFAX] requires that offramp gateways implemented using SMTP implement DSN [RFC1891], and this document provides extensions to message format of delivery status notifications [RFC1894] and error codes [RFC1893] to provide better support for fax offramps implemented as SMTP servers. 2. Introduction This document describes the following enhancements to DSN [RFC1891-1894] for fax: * fields for call length, dialed number, and number of pages transmitted (section 3) * enhanced status codes for fax-specific errors (section 4) [FAX-REQ] should be consulted for detailed background information. 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 . 2.1. Definitions offramp: A device which receives an SMTP message, calls a fax machine on the GSTN, translates the incoming SMTP message to a fax image, and transmits the fax image to the remote fax machine over the GSTN. GSTN: Global Switched Telephone Network. 3. Delivery Status Notification Message Fields A message that is gatewayed by a fax offramp will cause a telephone call to be made. This section describes mechanisms for the fax offramp to provide information about the telephone call: the the length of the call, number of pages transmitted, and the dialed telephone number. 3.1. New Message Fields Two new per-recipient extension fields, as described in [RFC1894 section 2.3], are defined using the ABNF format described in [RFC2234]: extension-field = call-duration / transmitted-pages call-duration = "Fax-Call-Duration" ":" elapsed-time transmitted-pages = "Fax-Transmitted-Pages" ":" xmit-pages elapsed-time = hour ":" minute ":" second [ ":" hundred ] hour = 2DIGIT minute = 2DIGIT second = 2DIGIT hundred = 2DIGIT xmit-pages = 1*DIGIT Examples: Fax-Call-Duration: 06:30:23.32 Fax-Call-Duration: 00:00:45 Fax-Transmitted-Pages: 104 Fax-Transmitted-Pages: 0 3.2. Use of Existing Message Fields The Final-Recipient field can indicate the actual number dialed. Reference [RFC1894, section 2.3.2], for the format of the Final-Recipient field. Delivery Status Notifications compliant with this document should have an "address-type" is "e164". The "generic-address" is a telephone number in the format of "global-phone", which is defined in [RFC2303]. Examples: Final-Recipient: e164; +1-408-457-5208 Final-Recipient: e164; +599-78760 4. Enhanced Mail System Status Codes While Enhanced Mail System Status Codes [RFC1893] is quite complete in its description of events specific to email, it does not provide error codes which map directly to all the error codes necessary for other services such as gatewaying to GSTN-based fax. This document describes how existing codes from [ENH-CODES] can be used with a fax offramp, and documents new codes that are necessary to support fax offramps. [ENH-CODES] allows new codes to be defined. The following table maps fax-specific codes to [ENH-CODES] codes where possible, and defines new fax-specific codes if [ENH-CODES] doesn't already have a suitable mapping. 4.1. New Enhanced Mail System Status Codes for Fax The new fax-specific per-recipient codes are: "X.2.50 no carrier" The number was successfully dialed, but no fax carrier was ever heard by the sending fax modem. This is useful as a persistent transient (4.X.X) or permanent error (5.X.X). "X.2.51 unable to train" The number was successfully dialed, and a fax carrier was heard, but the fax modem was unable to communicate with the remote fax machine successfully. This is useful as a persistent transient error (4.X.X). "X.2.52 no confirmation received" After transmission of a page to the remote fax machine the remote fax machine did not acknowledge receiving the page. This is useful as a persistent transient error (4.X.X). 4.2. Use of Existing Enhanced Mail System Status Codes Many of the codes described in [ENH-CODES] map well to fax offramp failure and success codes, and should be used to promote interoperability between fax and email. The text shown in parentheses is from [RFC1893]. "X.1.1 No such telephone number" ("Bad destination mailbox address" in [RFC1893]) The telephone number does not exist or is not a dialable telephone number. This code is only useful for permanent failures (5.X.X). "X.1.3 Unable to parse telephone number" ("Bad destination mailbox address syntax" in [RFC1893]) The destination address was syntactically invalid. This can apply to any field in the address. This code is only useful for permanent failures (5.X.X). "X.4.1 No answer" ("No answer from host" in [RFC1893]) The outbound connection attempt was not answered. This is useful for both permanent (5.X.X) and persistent transient error (4.X.X). "X.3.2 Persistently Busy" ("System not accepting network messages" in [RFC1893]) The dialed telephone number was busy. This is useful for both permanent (5.X.X) and presistent transient errors (4.X.X). 5. Security Considerations The Final-Recipient could disclose long-distance access codes that would be otherwise unknown to the sender. 6. Acknowledgments 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. [RFC1891] K. Moore, "SMTP Service Extension for Delivery Status Notifications", RFC 1891, January 1996. [RFC1893] G. Vaudreuil, "Enhanced Mail System Status Codes", RFC 1893, January 1996. [RFC1894] K. Moore, G. Vaudreuil, "An Extensible Message Format for Delivery Status Notifications", RFC 1894, January 1996. [RFC2303] C. Allocchio, "Minimal PSTN address format in Internet Mail", RFC 1303, 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. 9. Copyright Copyright (C) The Internet Society 1998. 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 implmentation 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. 10. Authors' Addresses 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 Larry Masinter Xerox Palo Alto Research Center 3333 Coyote Hill Road Palo Alto, CA 94304 USA Fax: +1 415 812 4333 EMail: masinter@parc.xerox.com