From: jpalme@dsv.su.se (Jacob Palme DSV)
Subject: How to map conference name in IPM-like headings
Newsgroups: comp.protocols.iso.x400
X400-Received: by /PRMD=SUNET/ADMD=_/C=SE/;
	Relayed; 27 Dec 92 12:11:02+0100
Date: 27 Dec 92 11:11:00 GMT

During my work of revision of the ISO/CCITT Group Communication working
papers, I have come to one very important issue.

Group Communication Contributions are sent to computer conferences,
just like IPM Messages are sent to users or distribution lists.

How should one then represent the names of the computer conferences
when transporting a contribution through the MTS.

Alternative 1: Use the existing primary-recipients, copy-recipients
and blind-copy-recipients heading fields.

Alternative 2: Use a new heading field.

Advantage with alternative 1:

(a) An ordinary MHS UA can input messages to computer conferences.
The conferences may look like distribution lists to such a user.

(b) An ordinary MHS UA can receive messages coming from computer
conferences. The conferences may look like distribution lists.

However, (a) and (b) are strictly only necessary conditions for
the information in the MTS envelope. The content heading might
use alternative 2, a new heading field when delivering a contribution
to an MHS UA, but then, of course, the MHS UA will not be able
to understand this heading field.

(c) An originator might not even have to know whether the ORName
he is sending a message to is actually an individual, a distribution
list or a computer conference. And sometimes this would be natural.
It is not necessary for someone who sends a message to for example
"The boss of company XYZ" to know whether this company has chosen to
distribute such incoming messages to a single individual, to a
distribution list, to a computer conference or to some other kind of
distribution tool used within that company.

(d) This is more close to IPMmessaging than alternative 2.

Advantage with alternative 2:

(a) It might be neater not to reuse existing fields for not quite the
same purpose.

(b) A problem with alternative 1 is how to distinguish between
submissions and accepted contributions to pre-moderated conferences.
The same message can at some stage of its processing be a submission
in one of the conferences it is sent to, and be an accepted contri-
bution in another, so it is necessary to indicate whether the
contribution is accepted or not on a per-recipient basis. This is
not easily done using the existing IPM heading syntax.

If alternative 1 is chosen, acceptance information will have to
be given somewhere else. For example, the DL history in the envelope
will indicate whether the message arrived from something which in
MHS terminology looks like a distribution list, but which for group
communication may represent a group activity to which the contribution
has been submitted and is resent from.

Another possible solution to the handling of pre-moderated conferences
is to use IPM forwarding. If this is done, then accepted entries
in pre-moderaded conferences will have an outer heading, with the
moderator as originator, and a body part, with the original submission
as its content. The advantage with doin this is

(a) The problem discussed above disappears

(b) There is no need to modify the original heading of the incoming
submission, it can be redistributed exactly as it is.

A disadvantage might be that messages coming from computer conferences
will look less like messages coming from distribution lists to
ordinary IPM UA-s receiving them.

If anyone has any comments on this, please send them to me!