ISO/IEC 8326:1996 情報技術—オープンシステム相互接続—セッションサービスの定義 | ページ 2

2.1 同一の推奨事項 |国際規格

Foreword

ISO (the International Organization for Standardization) and IEC (the International Electrotechnical Commission) form the specialized system for worldwide standardization. National bodies that are members of ISO or IEC participate in the development of International Standards through technical committees established by the respective organization to deal with particular fields of technical activity. ISO and IEC technical committees collaborate in fields of mutual interest. Other international organizations, governmental and non-governmental, in liaison with ISO and IEC, also take part in the work.

In the field of information technology, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1. Draft International Standards adopted by the joint technical committee are circulated to national bodies for voting. Publication as an International Standard requires approval by at least 75 % of the national bodies casting a vote.

International Standard ISO/IEC 8326 was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology, Subcommittee SC 21, Open Systems Interconnection,data management and open distributed processing, in collaboration with ITU-T. The identical text is published as ITU-T Recommendation X.215.

This second edition cancels and replaces the first edition (ISO 8326:1987), which has been technically revised. It also incorporates Amendment 4:1992.

Annex A forms an integral part of this International Standard.

Introduction

This Recommendation | International Standard is one of a set of Recommendations | International Standards produced to facilitate the interconnection of computer systems.

This Recommendation | International Standard is related to other Recommendations | International Standards in the set as defined by the Reference Model for Open Systems Interconnection. The Reference Model subdivides the area of standardization for interconnection into a series of layers of specification, each of manageable size.

The purpose of this Recommendation | International Standard is to define the service provided to the Presentation Layer at the boundary between the Session and Presentation Layers of the Reference Model. The session service is provided by the session protocol making use of the services available from the Transport Layer. This Recommendation | International Standard also defines the session service characteristics which the presentation protocol may exploit. The relationship between the Recommendations | International Standards for the session service, session protocol, transport service, and the presentation protocol is illustrated in Figure Intro. 1 below.

It is recognized that, with respect to session Quality of Service (described in clause 10), work is still in progress to provide an integrated treatment of QOS across all of the layers of the OSI Reference Model and to ensure that the individual treatments in each layer service satisfy overall QOS objectives in a consistent manner. As a consequence, an addendum may be added to this Recommendation | International Standard at a later time which reflects further QOS developments and integration.

2 Normative references

The following Recommendations and International Standards contain provisions which, through reference in this text, constitute provisions of this Recommendation | International Standard. At the time of publication, the editions indicated were valid. All Recommendations and International Standards are subject to revision, and parties to agreements based on this Recommendation | International Standard are encouraged to investigate the possibility of applying the most recent edition of the Recommendations and International Standards listed below. Members of ISO and IEC maintain registers of currently valid International Standards. The Telecommunication Standardization Bureau of the ITU maintains a list of currently valid ITU-T Recommendations.

2.2 Paired Recommendations | International Standards equivalent in technical content

3 Definitions

For the purposes of this Recommendation | International Standard, the following definitions apply.

3.1 Reference Model definitions

This Recommendation | International Standard is based on the concepts developed in ITU-T Rec. X.200 | ISO/IEC 7498-1, and makes use of the following terms defined in it:

• a) expedited-session-service-data-unit;
• b) session connection;
• c) Session Layer;
• d) session service;
• e) session-service-access-point;
• f) session-service-data-unit ;
• g) Transport Layer;
• h) duplex;
• i) half-duplex.

3.2 Service convention definitions

This Recommendation | International Standard also makes use of the following terms defined in ITU-T Rec. X.210 | ISO/IEC 10731, as they apply to the Session Layer:

• a) service-user;
• b) service-provider;
• c) primitive;
• d) request;
• e) indication;
• f) response;
• g) confirm.

3.3 Session service definitions