Network Working Group G. Parsons Internet Draft Nortel Networks Document: Category: Best Common Practice January 18, 2002 Real-time Facsimile (T.38) - image/t38 MIME Sub-type Registration Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. 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 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 a "work in progress". The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. 1. Abstract This document describes the registration of the MIME sub-type image/t38. The encoding is defined by [T.38] and is intended for use as an SDP media descriptor. 2. Conventions used in this document The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC-2119 [REQ]. Parsons Expires 18/07/02 [Page 1] Internet Draft image/t38 January 18, 2002 3. Overview This document describes the registration of the MIME sub-type image/t38. The encoding is defined by [T.38] and is intended for use as an SDP media descriptor. 4. T.38 Definition ITU-T Recommendation T.38 [T.38] describes the technical features necessary to transfer facsimile documents in real-time between two standard Group 3 facsimile terminals over the Internet or other networks using IP protocols. The Recommendation allows the use of either TCP or UDP depending on the service environment. ITU-T Recommendation T.38 Annex D [T.38D] describes system level requirements and procedures for internet aware facsimile implementations and internet aware facsimile gateways conforming to ITU-T T.38 to establish calls with other ITU-T T.38 implementations using the procedures defined in IETF RFC 2543 (SIP) and IETF RFC 2327 (SDP). 4.1 image/t38 Usage [T.38D] describes that the image/t38 media type is intended to indicate a T.38 media stream in SDP. This media type registration is not intended for email usage. 5. IANA Registration To: ietf-types@iana.org Subject: Registration of Standard MIME media type image/t38 MIME media type name: image MIME subtype name: t38 Required parameters: none Optional parameters: none Encoding considerations: Binary Parsons Expires 18/07/02 [Page 2] Internet Draft image/t38 January 18, 2002 Security considerations: This content denotes a facsimile bit stream that may or may not be encrypted. Interoperability considerations : This MIME media subtype is intended to be used as a parameter by SDP in SIP call setup for T.38 as described in ITU-T Rec. T.38 Annex D. Any use of this media type by email applications is not defined and as a result is not guaranteed to interoperate with a T.38 stream. Published specification: ITU-T Recommendation T.38, 'Procedures for real-time Group 3 facsimile communication over IP networks', June 1998. ITU-T Recommendation T.38 Amendment 2 Annex D, 'SIP/SDP Call Establishment Procedures', February 2000. A copy of these specifications can be found in: http://www.itu.int/rec/recommendation.asp?type=folders& lang=e&parent=T-REC-T.38 Applications which use this media type: Real-time facsimile (fax) Additional information: Magic number(s): II (little-endian): MM (big-endian): File extension(s): .T38 Macintosh File Type Code(s): T38 Person & email address to contact for further information: Glenn W. Parsons gparsons@nortelnetworks.com Intended usage: COMMON Change controller: Glenn Parsons 6. References [REQ] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. Parsons Expires 18/07/02 [Page 3] Internet Draft image/t38 January 18, 2002 [MIME4] N. Freed and N. Borenstein, "Multipurpose Internet Mail Extensions (MIME) Part Four: Registration Procedures", RFC 2048, Innosoft, First Virtual, Nov 1996. [SDP] M. Handley and V. Jacobson, "SDP: Session Description Protocol", RFC 2327, April 1998. [T.38] ITU-T Recommendation T.38, 'Procedures for real-time Group 3 facsimile communication over IP networks', June 1998. [T.38D] ITU-T Recommendation T.38 Amendment 2 Annex D, 'SIP/SDP Call Establishment Procedures', February 2000. 7. Author's Addresses Glenn W. Parsons Nortel Networks P.O. Box 3511, Station C Ottawa, ON K1Y 4H7 Canada Phone: +1-613-763-7582 Fax: +1-613-763-2697 Email: gparsons@nortelnetworks.com 8. 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