Network Working Group
Request for Comments: 2161
Category: Experimental

H. Alvestrand
UNINETT
January 1998

A MIME Body Part for ODA

Status of this Memo

This memo defines an Experimental Protocol for the Internet community. It does not specify an Internet standard of any kind. Discussion and suggestions for improvement are requested. Distribution of this memo is unlimited.

Copyright Notice

    Status of this Memo ........................................    1
   1 Introduction ..............................................    1
   1.1 The Application/ODA MIME content-type ...................    1
   1.2 ODA - application/oda ...................................    2
   2 Security Considerations ...................................    3
   3 References ................................................    4
   4 Author's Address ..........................................    4
   5 Full Copyright Statement ..................................    5

1. Introduction

This document contains the definitions, originally contained in RFC 1495 and RFC 1341, on how to carry ODA in MIME, and how to translate it to its X.400 representation.

1.1. The Application/ODA MIME content-type

   The "ODA" subtype of application is used to indicate that  a body
   contains  information  encoded according to the Office Document
   Architecture  [ODA]   standards,  using  the  ODIF representation
   format.   For  application/oda, the Content-Type line should also
   specify an attribute/value  pair  that indicates  the document
   application profile (DAP), using the key word "profile", and the
   document class, using the keyword "class".

For the keyword "class", the values "formatted", "processable" and "formatted-processable" are legal values.

   Thus an appropriate header field  might look like this:
   
   Content-Type:  application/oda; profile=Q112; class=formatted

Consult the ODA standard [T.411] for further information.

The Base64 content-transfer-encoding is appropriate for carrying ODA.

1.2. ODA - application/oda

   X.400 Body Part: ODA
   MIME Content-Type: application/oda
   Conversion: None
   Comments:
   
   The ODA body part is defined in the CCITT document T.411 [T.411],
   appendix E, section E.2, "ODA identification in the P2 protocol of
   MHS"

An abbreviated version of its ASN.1 definition is:

    oda-body-part EXTENDED-BODY-PART-TYPE
            PARAMETERS      OdaBodyPartParameters
            DATA            OdaData
            ::= id-et-oda

OdaBodyPartParameters ::= SET {

            document-application-profile    [0] OBJECT IDENTIFIER
            document-architecture-class     [1] INTEGER {
                                            formatted (0)
                                            processable (1)
                                            formatted-processable(2)}}
    
    id-et-oda OBJECT IDENTIFIER ::= { 2 8 1 0 1 }

Mapping from X.400 to MIME, the following is done:

The Parameters.document-application-profile is mapped onto the MIME parameter "profile" according to the table below.

   Profile         OBJECT IDENTIFIER
   
   Q112            { iso (1) identified-organization (3) ewos (16)
                     eg (2) oda (6) profile (0)  q112 (1) }

The Parameters.document-architecture-class is mapped onto the MIME parameter "class" according to the table below.

   String                  Integer
   
   formatted               formatted(0)
   processable             processable(1)
   formatted-processable   formatted-processable(2)

NOTE:

This parameter is not defined in RFC 1341.

The body of the MIME content-type is the Data part of the ODA body part.

When mapping from MIME to X.400, the following steps are done:

The Parameters.document-application-profile and Parameters.document- architecture-class are set from the tables above. If any of the parameters are missing, the values for Q112 and formatted-processable are used.

It is an option for the gateway implementor to try to access them from inside the document, where they are defined as

   document-profile.document-characteristics.document-architecture-class
   
   document-profile.document-characteristics.document-application-
   profile

Gateways are NOT required to do this, since the document- characteristics are optional parameters. If a gateway does not, it simply uses the defaulting rules defined above.

The OBJECT IDENTIFIERs for the document application profile and for ODA {2 8 0 0} must be added to the Encoded Information Types parameter of the message envelope.

2. Security Considerations

ODA body parts have the natural propensity of complex structures that it is hard to find out what the parts are capable of.

Moreover, ODA is an extensible architecture, where new content portions may be added at any time, so that the threats posed by this body part may change over time.

However, no security risks related to ODA are known at this time.

3. References

[MIME]

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

[T.411]: CCITT Recommendation T.411 (1988), Open Document Architecture (ODA) and Interchange Format, Introduction and General Principles.

4. Author's Address

Harald Tveit Alvestrand
UNINETT
Postboks 6883 Elgeseter
N-7002 TRONDHEIM

   Phone: +47 73 59 70 94
   EMail: Harald.T.Alvestrand@uninett.no

5. Full Copyright Statement

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.