RFC 3362

Real-time Facsimile (T.38) - image/t38 MIME Sub-type Registration

📅 published September 2002, from ietf

Real-time Facsimile (T.38) - image/t38 MIME Sub-type Registration 📠✨

RFC: 3362 🎀 Author: Glenn W. Parsons, Nortel Networks 💅 Category: Standards Track 🦋 Date: August 2002 🌸 Obsoletes / Updates: nothing listed in the title block 🫶

Status of This Memo 📣

okay so this doc is an Internet standards track protocol spec for the Internet community, and it's literally asking for discussion and suggestions for improvements 🔥. If you want the current standardization state and status of this protocol, check the current edition of the "Internet Official Protocol Standards" (STD 1) 📚. Distribution of this memo is unlimited 🌈.

Copyright (C) The Internet Society (2002). All Rights Reserved 💜.

Abstract 🧚

This doc registers the MIME sub-type image/t38 🦋. The encoding is defined by ITU Recommendation T.38, and it's meant to be used as a 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 in BCP 14, RFC 2119 [REQ] 🔥. These are the words that carry the weight, so pay attention to them 👑.

2. Overview ✨

This doc registers the MIME sub-type image/t38 🦋. The encoding is defined by [T.38] and is meant for use as an SDP media descriptor 🌸.

3. T.38 Definition 📠

ITU-T Recommendation T.38 [T.38] describes the technical features needed to transfer fax documents in real time between two standard Group 3 facsimile terminals over the Internet or other networks using IP protocols 🌐. The Recommendation lets you use either TCP or UDP, depending on the service environment 💖.

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 that conform to ITU-T T.38. These let them set up calls with other ITU-T T.38 implementations using the procedures defined in IETF RFC 2543 [SIP-99] and IETF RFC 2327 [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], those 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 meant 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.

   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 Parsons

5. Security Considerations 🔐

Security considerations for this media type are discussed in the MIME type registration that appears in section 4 😭. Go read that bit, it's the whole security story for this type 💀.

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", BCP 13, RFC 2048, November 1996.
  • [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.com

Copyright (C) The Internet Society (2002). All Rights Reserved.

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Acknowledgement 🌷

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