Network Working Group G. Parsons
Request for Comments: 3362 Nortel Networks
Category: Standards Track August 2002
Real-time Facsimile (T.38) - image/t38
MIME Sub-type Registration
Status 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 in BCP 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 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], 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 Parsons
5. Security Considerations
Security considerations for this media type are discussed in the MIME
type registration that appears in section 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", BCP
13, 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.com
Parsons Standards Track [Page 4]
RFC 3362 MIME Sub-type image/t38 August 2002
8. 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]