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Network Working Group                                         G. ParsonsRequest for Comments: 3362                               Nortel NetworksCategory: Standards Track                                    August 2002Real-time Facsimile (T.38) - image/t38MIME Sub-type RegistrationStatus of this Memo   This document specifies an Internet standards track protocol for the   Internet community, and requests discussion and suggestions for   improvements.  Please refer to the current edition of the "Internet   Official Protocol Standards" (STD 1) for the standardization state   and status of this protocol.  Distribution of this memo is unlimited.Copyright Notice   Copyright (C) The Internet Society (2002).  All Rights Reserved.Abstract   This document describes the registration of the MIME sub-type   image/t38.  The encoding is defined by ITU Recommendation T.38 and is   intended for use as an Session Description Protocol (SDP) media   descriptor.1.  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 inBCP 14,RFC 2119   [REQ].2.  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.3.  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.Parsons                     Standards Track                     [Page 1]

RFC 3362                MIME Sub-type image/t38              August 2002   ITU-T Recommendation T.38 [T.38] Annex D 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 IETFRFC 2543 [SIP-99] and IETFRFC2327 [SDP].   Note that ITU-T T.38 Recommendation T.38 (04/02) [T.38] is an   aggregation of the original ITU-T Recommendation T.38 (06/98) [T.38-   98] and all of the subsequent Amendments and Corrigendum including   [T.38D-00].  While [T.38] and [T.38D-00] describe SIP procedures per   [SIP-99], the procedures can also be applied to the revised Session   Initiation Protocol specification [SIP].3.1  image/t38 Usage   Annex D of [T.38] 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.4.  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      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.Parsons                     Standards Track                     [Page 2]

RFC 3362                MIME Sub-type image/t38              August 2002      Published specification:         ITU-T Recommendation T.38, 'Procedures for real-time         Group 3 facsimile communication over IP networks', April         2002.         A copy of the T.38 specifications can be found at: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 Parsons5. Security Considerations   Security considerations for this media type are discussed in the MIME   type registration that appears insection 4.6. References   [REQ]      Bradner, S., "Key words for use in RFCs to Indicate              Requirement Levels",BCP 14,RFC 2119, March 1997.   [MIME4]    Freed, N. and N. Borenstein, "Multipurpose Internet Mail              Extensions (MIME) Part Four: Registration Procedures",BCP13,RFC 2048, November 1996.Parsons                     Standards Track                     [Page 3]

RFC 3362                MIME Sub-type image/t38              August 2002   [SDP]      Handley, M. and V. Jacobson, "SDP: Session Description              Protocol",RFC 2327, April 1998.   [SIP]      Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,              A., Peterson, J., Sparks, R., Handley, M. and E. Schooler,              "SIP: Session Initiation Protocol",RFC 3261, June 2002.   [SIP-99]   Handley, M., Schulzrinne, H., Schooler, E. and J.              Rosenberg, "SIP: Session Initiation Protocol",RFC 2543,              March 1999.   [T.38]     ITU-T Recommendation T.38, 'Procedures for real-time Group              3 facsimile communication over IP networks', April 2002.   [T.38-98]  ITU-T Recommendation T.38, 'Procedures for real-time Group              3 facsimile communication over IP networks', June 1998.   [T.38D-00] ITU-T Recommendation T.38 Amendment 2 Annex D, 'SIP/SDP              Call Establishment Procedures', February 2000.7. Authors' Address   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.comParsons                     Standards Track                     [Page 4]

RFC 3362                MIME Sub-type image/t38              August 20028. Full Copyright Statement   Copyright (C) The Internet Society (2002).  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.Acknowledgement   Funding for the RFC Editor function is currently provided by the   Internet Society.Parsons                     Standards Track                     [Page 5]