rfc1616.txt

著名的RFC文档,其中有一些文档是已经翻译成中文的的.

Network Working Group                          RARE WG-MSG Task Force 88
Request for Comments: 1616                                      May 1994
RARE Technical Report: 10
Category: Informational


     X.400(1988) for the Academic and Research Community in Europe

            A report by the RARE Task Force on X.400(1988)
             of the RARE Working Group on Mail & Messaging

Status of this Memo

   This memo provides information for the Internet community.  This memo
   does not specify an Internet standard of any kind.  Distribution of
   this memo is unlimited.

1.  Abstract

   The European research and development community, as represented by
   the member research networks of RARE, has lead the deployment within
   the global R&D community of X.400 electronic messaging services, as
   specified in the international recommendations CCITT X.400(1984), for
   more than five years. As a result of providing such services to the
   European R&D users it has become clear that there is an existing and
   ever increasing demand from these users for new and enhanced
   electronic messaging services and product to be used to communicate
   within the R&D community but within commercial service providers and
   organisations as well.

   It is also clear that new services, such as Multimedia messaging and
   Secure messaging, and the resulting products promise dramatic
   benefits and opportunities, for not only the R&D community but also
   for the wider commercial, industrial and public communities, in terms
   of facilitating innovative ways of working and living which can only
   enhance the missions and goals of the respective communities. Not
   least the establishment of globally pervasive messaging services
   between all users, R&D and commercial, is facilitated by the early
   adoption of such advanced new services. An indication of the
   importance of such a messaging service can be appreciated if one
   considers that in many organizations (especially commercially based)
   messaging may be the only method to communicate between independent
   organizations due to security considerations and lower layer network
   differences.

   The Commission of European Communities (CEC) VALUE subprogram II has
   been established to support initiatives relating to the development
   and adaptation of R&D networks in member states.  Amongst other



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RFC 1616     X.400(88) for European Academics and Research      May 1994


   initiatives the VALUE program supports X.400 initiatives in certain
   countries. VALUE support has so far been limited to X.400(1984)
   initiatives, as X.400(1984) has up until now been the dominating OSI
   services. However as X.400(1988) implementations have started to
   appear a VALUE funded study of the X.400(1988) aspects of messaging
   and their impact on the R&D community was felt necessary. This report
   is one of the results of that study.

   The report documents the results of a task force on X.400(1988)
   deployment of the RARE Mails and Messaging Work Group during the
   period from November 1992 until October 1993. Open reviews of the
   report have occurred in the RARE Mail and Messaging Work Group and
   within the IETF X.400ops Working Group.

   The scope of the report is limited to deployment of X.400(1988)
   services, and as such the report does not contain any recommendations
   on development and deployment of Internet RFC 822 / MIME/ PEM related
   (pilot) services. However, since the report shows that both
   X.400(1988) and RFC 822 / MIME / PEM will be developed and used
   within the European R&D community, such a pilot should also
   considered.  Note: RFC 822 is also known as Internet STD 11.

   Circulation of this report is unlimited. Comments on this report may
   be sent to the e-mail distribution list:

    RFC 822: [e-mail]
    X.400:   S=wg-msg;O=rare;P=surf;A=400net;C=nl;

Task Force Members:

    Claudio Allocchio (INFN),
    Harald T. Alvestrand (SINTEF),
    James C. I. Craigie (JNT),
    Urs Eppenberger (SWITCH),
    Frode Hernes (maXware),
    Jeroen Houttuin (RARE),
    Erik Huizer (SURFnet) - chairman,
    Steve Kille (ISODE Consortium),
    James A. (Jim) Romaguera (NetConsult).

    Editors: James A. (Jim) Romaguera & Erik Huizer

   The work of this Task Force has been funded by the Commission of
   European Communities (CEC) VALUE subprogram II, Stichting SURF and
   SURFnet bv.






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RFC 1616     X.400(88) for European Academics and Research      May 1994


Table of Contents

   1.  Abstract                                                      1
   2.  Management Summary                                            3
   3.  Framework for the report                                      6
   4.  Present situation of European Messaging                       7
      4.1. Messaging services                                        7
      4.2. Requirements for messaging                                8
             4.2.1. User Oriented                                    9
             4.2.2. Service provider viewpoint                      10
      4.3. Messaging capabilities                                   11
   5.  Possible solutions for providing globally pervasive
       messaging                                                    12
      5.1. PC LAN E-mail systems                                    13
      5.2. RFC 822, MIME and PEM services                           15
      5.3. X.400 - 1984 and 1988                                    19
   6.  Migration to X.400(1988)                                     23
      6.1. PC LAN E-mail systems                                    25
      6.2. RFC 822, MIME and PEM services                           25
      6.3. X.400(1984) services                                     27
      6.4. Mail-11 services                                         28
   7.  Benefits of migrating to X.400(1988) and the involved costs  28
   8.  Main Recommendations                                         33
   9.  Security Considerations                                      34
   10. Reading List and Bibliography                                35
   11. Terminology                                                  37
   Appendix A - Elaboration on the main recommendations             38
   Appendix B - A number of detailed guidelines.                    40
   Authors' Addresses                                               44

2.  Management Summary

   This document reports the results of study of the X.400(1988) aspects
   of messaging and their impact on the R&D community. The study was
   funded by the CEC under VALUE Subprogram II and has been carried out
   by a task force on the RARE Mail Working Group.  The document is
   targeted at technical decision makers as well as those who would fund
   activity in this area.

   The document presents the existing situation as regards the
   predominate messaging technologies within Europe. These are presented
   within the context of a number of large messaging communities that
   are using these technologies:

    - RFC 822,
    - X.400(1984),
    - Mail-11 and
    - PC LAN messaging



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RFC 1616     X.400(88) for European Academics and Research      May 1994


   Three major European communities are referenced:

    - Commercial service providers
    - R&D community
    - Commercial organisations using messaging services.

   The report states the following facts:

    - The resources, human or financial, to operate multiple wide
      area messaging services connecting together independent
      organisations are high. As such it is desirable to try and
      keep to a minimum the number of such services. This statement
      is true for the R&D community but is also highly likely to be
      valid for the general European industry.

    - There are two publicly available technological standards
      that can be used by open communities, such as the R&D
      community and public service providers: the X.400(1984 and
      1988) recommendations and the Internet RFC 822 / MIME / PEM
      standards.

    - There is an established very large global user base of
      Internet RFC 822 and X.400(1984) messaging services. Both
      services have their own momentum within different parts of
      the user community, both are still developing and growing
      fast.

   The report concludes that X.400(1988) will be the preferred protocol
   for inter organizational connection for European industry and
   government and parts of the European R&D community.  RFC 822 / MIME /
   PEM will be the preferred protocol suite for inter-organisational
   connection for the Internet community and, as products are already
   widely available, it is the preferred protocol for parts of the
   European R&D community.

   The goal of European pervasive messaging - incorporating Industry,
   Government and Academia - would be best accommodated and reached by
   the establishment of a single messaging service.  However taking the
   above into account, this is not feasible, as X.400(84 and 88) and RFC
   822( and MIME) based services will be around for a long time to come.
   To increase the functionality of Wide Area E-mail services there is a
   clear necessity to:

    - migrate RFC 822 services to a RFC 822 / MIME / PEM service.
      A MIME based service offers more functionality to the user
      than a plain RFC 822 service.

    - migrate existing X.400 services to a X.400(1988) service.



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RFC 1616     X.400(88) for European Academics and Research      May 1994


      Due to the lack of scalability of the X.400(1984) service in
      terms of extra functionality, it will become increasingly
      difficult to meet the needs of research users of existing
      X.400(1984) services unless an X.400(1988) service is put
      into place.

    - provide a transparent gateway between X.400(1988) and RFC
      822/MIME/PEM. For the European R&D community it is essential
      to have a transparent gateway between the X.400(1988) service
      and the RFC 822 / MIME / PEM service, thus ensuring
      connectivity between these two services with a maximum
      functionality.

   Such a gateway is technically feasible and it is an essential part of
   an unified E-mail service. Without such a standardised gateway the
   overall E-mail service would deteriorate.

   The lack of open standards for the PC LAN messaging systems
   discourages their use as 'backbone' messaging technologies within
   open communities. However the products that these systems deliver to
   end users ensures that their already large share of the messaging
   market will continue to exist for some time. Thus it is also
   essential that strategies that allow these systems to be 'seamlessly'
   integrated within the global messaging community are put in place.
   Not least due to the indications that the main messaging vendors are
   developing X.400(1988) and RFC 822/MIME gateways, a strategy to link
   these systems together via X.400 and RFC 822 should be developed.

   The report concludes with a set of recommendations, the main one
   being the establishment of a X.400(1988) European pilot messaging
   service for the R&D community. This pilot should include the
   establishment of a transparent gateway service between X.400(1988)
   and RFC 822/MIME. The goal of a European pilot is to ensure the
   successful deployment of a European wide operational X.400(1988)
   service that is pervasive and meets the needs of users. By collecting
   together the issues related to the establishment of a European
   X.400(1988) service, this report acts as a focal point and stimulant
   for discussion on this topic within the R&D community. In the report
   a summary of the benefits and problems of each of the above messaging
   technologies within the context of achieving a global messaging
   service, of which the R&D community is one part, is presented.
   Further the document identifies issues, strategies and
   recommendations related to the migration and coexistence of these
   technologies within the scope of mainly the European R&D community
   but also in relation to other messaging communities. A cost / benefit
   analysis on the establishment of a European wide pilot X.400(1988)
   messaging service is also presented. Finally a reading list of
   references related to this subject has been compiled.



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RFC 1616     X.400(88) for European Academics and Research      May 1994