S.Kille@cs.ucl.ac.UK (Steve Kille) (11/29/90)
I would appreciate comments on the following.
Steve
X.400 1988 to 1984 downgrading
S.E. Kille
November 1990
Abstract
This document considers issues of downgrading from X.400(1988)
to X.400(1984) [MHS88a ], [MHS84 ]. COSINE Study 8.2 by J.A.I. Craigie
and Annexe B of X.419 are considered as base documents [Cri88],
[MHS88b ]. Only additions and alterations to these specifications are
considered.
1 MTS
No changes need to be specified, other than those described later for address
handling.
2 IPM Formats
This is not considered in X.419. The following notes/extensions are made
to COSINE Study 8.2:
The following should be done:
1. The Cosine study suggests mapping of all new P2(88) body parts into
the externally defined body part of P2(84). This may not be helpful
for a lot of 84 UAs. The following alternatives are noted:
fflConvert the body part into a defined format of P2(88) such as
IA5 text
fflReplace the body part with a text body part, indicating that
another body part was present and could not be handled.
fflBounce the message back to the originator
The best choice will depend on the exact application of the gateway.
2. If a directory name is present, append it to the Free Form Name using
the \User Friendly Name" syntax, enclosed in round brackets [Kil90b].
3. Map O/R addresses, as described in the Section 3.
1
3 Addressing
In general there is a problem with O/R addresses which use 88 specific fea-
tures. The X.419 approach will mean that addresses using these features
cannot be specified from 84 systems. This is unacceptable. The approach
proposed in a Cosine Study 8.2 has a number of problems, which are dis-
cussed in Appendix A.
The approach proposed here is to use a DDA \X400-88". The DDA value
is an std-or encoding of the address as defined in RFC 1148 [Kil90a]. This
will allow source routing through an appropriate gateway. This solution is
general, and does not require co-operation. For example:
88:
CN=Postmaster; O=YY; PRMD=XX; ADMD=ZZ; C=US;
84:
O=MHS-Relay; PRMD=UK.AC; C=GB;
DDA.X400-88=/CN=Postmaster/O=YY/PRMD=XX/ADMD=ZZ/C=US/;
The std-or syntax can use IA5 characters not in the printable string set
(typically to handle teletext versions). To enable this to be handled, the
std-or encoded in encapsulated into printable string using the mappings of
Section 3.4 of RFC 1148.
References
[Cri88] J.A.I. Criagie. Migration strat-
egy for x.400(84) to x.400(88)/MOTIS. COSINE Specification
Phase 8.2, RARE, 1988.
[Kil90a] S.E. Kille. Mapping between X.400(1988) / ISO 10021 and RFC
822. Request for Comments 1148, DDN Network Information
Center, SRI International, March 1990. Also available as Mail-
Group Note 23.
[Kil90b] S.E. Kille. Using the osi directory to achieve user friendly nam-
ing. Research Note RN/90/29, Department of Computer Science,
University College London, February 1990. Internet Draft: draft-
ietf-osids-friendlynaming-00.txt, ps.
[MHS84] Recommendations X.400, October 1984. CCITT SG 5/VII, Mes-
sage Handling Systems: System Model - Service Elements.
[MHS88a] CCITT recommendations X.400/ ISO 10021, April 1988.
CCITT SG 5/VII / ISO/IEC JTC1, Message Handling: System
and Service Overview.
[MHS88b] CCITT recommendations X.419/ ISO 10021, April 1988.
CCITT SG 5/VII / ISO/IEC JTC1, Message Handling: Pro-
tocol Specifications.
2
A Cosine Study 8.2 Address Downgrading
The approach proposed in a Cosine Study 8.2 of using a DDA \Common",
provides a solution for the Common Name attribute. This approach has the
following problems:
o It does not solve the mapping for all 88 specific attributes
o It does not deal with Teletext (T.61) variants of the attributes, which
are expected to become increasingly common.
o It will only be useful if it gets some standard recognition (i.e., is im-
plemented at all 84/88 gateways).
o Either the convention must be understood by all 88 systems, or there
needs to be a gateway upgrade form content type 2 to 22. Either seems
undesirable.
3behunin@logdis1.oo.aflc.af.MIL ("Roland Behunin;OO-ALC/LILABD") (11/29/90)
unscribe me roland behunin
kehres@touch.COM (Tim Kehres) (11/29/90)
Steve,
Your message references the following document:
[Cri88] J.A.I. Criagie. Migration strat-
egy for x.400(84) to x.400(88)/MOTIS. COSINE Specification
Phase 8.2, RARE, 1988.
Is this document available via anonymous ftp (or equivalent) anywhere? If
not, would it be possible (if there is enough interest) to post a copy to
this group?
Regards,
Tim Kehres <kehres@touch.com>NTIN36@gec-b.rutherford.ac.UK (Jim Craigie) (03/17/91)
From: Tim Kehres <kehres@com.touch>
Subject: Re: X.400 88 -> 84 downgrading
Date: Wed, 28 Nov 90 14:44:12 PST
Steve,
Your message references the following document:
[Cri88] J.A.I. Criagie. Migration strat-
egy for x.400(84) to x.400(88)/MOTIS. COSINE Specification
Phase 8.2, RARE, 1988.
Is this document available via anonymous ftp (or equivalent) anywhere? If
not, would it be possible (if there is enough interest) to post a copy to
this group?
Regards,
Tim Kehres <kehres@touch.com>
Unfortunately, this is only available on paper - but it is free!
It is available on request from:
COSINE Secretariat
c/o CEC DG XIII A2
200 rue de la Loi
Brussels
Belgium