MIXER body mapping: encapsulation of X.400 basic body parts

David Wilson <D.Wilson@isode.com> Fri, 04 April 1997 15:23 UTC

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cc: Harald.T.Alvestrand@uninett.no, S.Kille@isode.com, D.Wilson@isode.com
Subject: MIXER body mapping: encapsulation of X.400 basic body parts
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Date: Fri, 04 Apr 1997 16:20:01 +0100
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From: David Wilson <D.Wilson@isode.com>

I believe there is a problem with draft-ietf-mixer-bodymap-06.txt Section 3.2.

This states that:

       "Standard X.400 body parts may not be encoded directly by this
	mechanism [application/x400-bp], but may be encoded indirectly by
	first translating to the extended representation."

The significant problem is that there are standard X.400 bodyparts which
do not have an extended representation. Telex and iso6937Text are examples.

The other problem is that there are RFC-1494 gateways that do not do this
conversion, so a useful MIXER gateway needs to be able to deal correctly
with standard X.400 bodyparts not in the extended form.

Therefore the use of the bp_type=<integer> form should continue.

I suggest:

In section 3.2:

The definition of the parameter should be:

	mime-parameter = "bp-type=" ( objectidentifier / integer )

with text following:

   If the body is a basic body part, the bp-type parameter is set to the
   number of the body part's context-specific tag, that is, the tag of
   the IPMS.Body.BodyPart component.
 
   If the body is an Extended Body Part, the bp-type parameter is set to
   the OBJECT IDENTIFIER from
 
            IPMS.body.externally-defined.data.direct-reference
 

(copied directly from RFC-1494).

The example should be introduced by:

	For example, an extended Videotext body part will have

The last two paragraphs should be dropped.

I have checked with Steve Kille on this, and he agrees.

regards

David Wilson                                        D.Wilson@isode.com
Isode Ltd.                                       Tel: +44 181 332 9091
http://www.isode.com                             Fax: +44 181 332 9019