[Docs] [txt|pdf] [Tracker] [Email] [Nits]

Versions: 00

AVT Working Group
Internet Draft                                                 P. Jones
<draft-jones-avt-text-red-00.txt>                   Cisco Systems, Inc.
Expires: May 2004                                         November 2003



                Registration of the text/red MIME Sub-Type


Status of this Memo

   This document is an Internet-Draft and is in full conformance with
   all provisions of Section 10 of RFC 2026.

   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."

   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.

Abstract

   This document defines the text/red MIME sub-type.  The packetization
   and usage of this MIME type, which is intended for use within SDP, is
   specified within RFC 2198 and RFC 2793, respectively.

1. Introduction

   Text is an important component of any multimedia communication
   system.  Like audio, the transport of text can benefit from the use
   of redundancy in order to improve reliability and end-user
   experience.

   RFC 2198 defines a payload format for audio data.  The format defined
   in that document is quite suitable for providing redundancy for text,
   as well as audio.

   RFC 2793 [1] specifies the use of RFC 2198 for the transport of
   redundant text data.



Jones                     Expires - May 2004                  [Page 1]

              Registration of the text/red MIME Sub-Type November 2003


   This memo provides the MIME sub-type registration information.

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 [4].

3. IANA Considerations

   One new MIME sub-type is to be registered, as described below:

      MIME media type name: text

      MIME subtype name: RED

      Required parameters:
        pt: a comma-separated list of RTP payload types.  Because
        comma is a special character, the list must be a quoted-string
        (enclosed in double quotes).  For static payload types, each
        list element is simply the type number.  For dynamic payload
        types, each list element is a mapping of the dynamic payload
        type number to an embedded MIME content-type specification for
        the payload format corresponding to the dynamic payload type.
        The format of the mapping is:

           dynamic-payload-type "=" content-type

        If the content-type string includes a comma, then the
        content-type string MUST be a quoted-string.  If the content-
        type string does not include a comma, it MAY still be quoted.
        Since it is part of the list which must itself be a quoted-
        string, that means the quotation marks MUST be quoted with
        backslash quoting as specified in RFC 2045 [5].  If the content-
        type string itself contains a quoted-string, then the
        requirement for backslash quoting is recursively applied.  To
        specify the text/RED payload format in SDP, the pt parameter
        is mapped to an a=fmtp attribute by eliminating the parameter
        name (pt) and changing the commas to slashes.  For example,
        'pt="101,102"' maps to 'a=fmtp:99 101/102'.

      Optional parameters: ptime, maxptime

      Encoding considerations:
        This type is only defined for transfer via RTP [3].

      Security considerations: Refer to section 4.

      Interoperability considerations: none


Jones                     Expires - May 2004                  [Page 2]

              Registration of the text/red MIME Sub-Type November 2003



      Published specification: RFC 2198

      Applications which use this media type:
        Text streaming and conferencing tools.

      Additional information: none

      Person & email address to contact for further information:
        Paul E. Jones
        E-mail: paulej@packetizer.com

      Intended usage: COMMON

      Author                        / Change controller:
        Paul E. Jones               | IETF avt WG
        paulej@packetizer.com       |

4. Security Considerations

   The security considerations listed in RFC 2198 apply.  Further, it
   should be understood that text data, perhaps even more so than audio
   data, is susceptible to unwanted modification that may lead to
   undesired results.

5. Normative References

   [1] Hellstrom, G., "RTP Payload for Text Conversation”, RFC 2793,
       May 2000.

   [2] Perkins, C., et al., "RTP Payload for Redundant Audio Data", RFC
       2198, September 1997.

   [3] Schulzrinne, et al., "RTP: A Transport Protocol for Real-Time
       Applications", RFC 3550, July 2003.

   [4] Bradner, S., "Key words for use in RFCs to Indicate Requirement
       Levels", RFC 2119, March 1997.

   [5] Freed, N., Borenstein, N., "Multipurpose Internet Mail
       Extensions (MIME) Part One: Format of Internet Message Bodies",
       RFC 2045, November 1996.

6. Author's Address

   Paul E. Jones
   Cisco Systems, Inc.
   7025 Kit Creek Rd.
   Research Triangle Park, NC 27709


Jones                     Expires - May 2004                  [Page 3]

              Registration of the text/red MIME Sub-Type November 2003


   Phone: +1 919 392 6948
   Email: paulej@packetizer.com

7. Intellectual Property Right Considerations

   The IETF takes no position regarding the validity or scope of any
   intellectual property or other rights that might be claimed to
   pertain to the implementation or use of the technology described in
   this document or the extent to which any license under such rights
   might or might not be available; neither does it represent that it
   has made any effort to identify any such rights.  Information on the
   IETF's procedures with respect to rights in standards-track and
   standards-related documentation can be found in BCP-11.  Copies of
   claims of rights made available for publication and any assurances of
   licenses to be made available, or the result of an attempt made to
   obtain a general license or permission for the use of such
   proprietary rights by implementors or users of this specification can
   be obtained from the IETF Secretariat.

   The IETF invites any interested party to bring to its attention any
   copyrights, patents or patent applications, or other proprietary
   rights which may cover technology that may be required to practice
   this standard.  Please address the information to the IETF Executive
   Director.

8. Full Copyright Statement

   Copyright (C) The Internet Society (2003).  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


Jones                     Expires - May 2004                  [Page 4]

              Registration of the text/red MIME Sub-Type November 2003


   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.











































Jones                     Expires - May 2004                  [Page 5]


Html markup produced by rfcmarkup 1.108, available from http://tools.ietf.org/tools/rfcmarkup/