1、National Standard of Canada CA N/CSA -IS O/IE C 84 73 -3-97 International Standard ISO/IEC 8473-3:1995 (first edition, 1995-03-15) has been adopted without modification as CSA Standard CAN/CSA-ISO/IEC 8473-3-97, which has been approved as a National Standard of Canada by the Standards Council of Can
2、ada. ISSN 031 7-5669 February 1997 Information technology - Protocol for providing the connectionless-mode network service: Provision of the underlying service by an X.25 subnetwork Technologies de Iinformation - Protocole de fourniture du service de reseau en mode sans connexion: Fourniture du serv
3、ice sous-jacent par un sous-reseau X.25 Reference number ISO/IEC 8473-3:1995(E LAssoclatlon canadlenne de normallsatlon (CSA), sous les auspices de laquelle cette Norme nationale a dtd prdparde, a re$u ses lettres patentes en 1919 et son accreditation au sein du Systbme de normes nationales par le C
4、onseil canadien des normes en 1973. Association daffiliation libre, sans but lucratif ni pouvoir de rdglementation, elle se consacre h Idlaboration de normes et B la certification. Les normes CSA reflhtent le consensus de producteurs et dusagers de partout au pays, au nornbre desquels se trouvent de
5、s fabricants, des consommateurs, des ddtaillants et des representants de syndicats, de corps professionnels et dagences gouvernementales. Lutilisation des normes CSA est trbs repandue dans Iindustrie et le commerce, et leur adoption I divers otdres de Idgislation, !ant municipal et provincial que ft
6、Sderal, est chose courante, particulibrement dans les dornaines de la santd, de la shcuritb, du bAtiment, de la construction et de Ienvironnement. Les Canadiens dun bout I Iautre du pays temoignent de leur appui au travail de normalisation mend par la CSA en participant bdndvolernent aux travaux des
7、 comites de la CSA et en appuyant ses objectifs par leurs cotisations de membres de soutien. Les quelque 7000 volontaires faisant partie des comites et es 2000 membres de soutien constituent Iensemble des membres de la CSA parmi lesquels ses administrateurs sont choisis. Les cotisations des membres
8、de soutien representent une source importante de revenu pour les services de soutien B la normalisation volontaire. LAssociation offre des services de certification et de mise B Iessai qui appuient et complbtent ses activitds dans le domaine de Idlaboration de normes. De manidre A assurer Iintdgrit6
9、 de son processus de certification, IAssociation procede de fagon rhgulihre et continue ZI Iexamen et I Iinspection des produits portant la marque CSA. Outre son sibge social et ses laboratoires B Etobicoke, la CSA posshde des bureaux rdgionaux dans des centres vitaux partout au Canada, de meme que
10、des agences dinspection et dessai dans huit pays. Depuis 1919, IAssociation a parfait les connaissances techniques qui lui permettent de remplir sa mission dentreprise, I savoir la CSA est un organisme de services independant dont la mission est doffrir une tribune libre et efficace pour la realisat
11、ion dactivites facilitant Mchange de biens et de services par IintermBdiaire de services de normalisation de certification et autres, pour repondre aux besoins de nos clients, tant I 18chells nationale quinternationale. The Canadian Standards Association (CSA), under whose auspices this National Sta
12、ndard has been produced, was chartered in 1919 and accredited by the Standards Council of Canada to the National Standards system in 1973. It is a not-for-profit, nonstatutory, voluntary membership association engaged in standards development and certification activities. CSA standards reflect a nat
13、ional consensus of producers and users - including manufacturers, consumers, retailers, unions and professional organizations, and governmental agencies. The standards are used widely by industry and commerce and often adopted by municipal, provincial, and federal governments in their regulations, p
14、articularly in the fields of health, safety, building and construction, and the environment. Individuals, companies, and associations across Canada indicate their support for CSAs standards development by volunteering their time and skills to CSA Committee work and supporting the Associations object
15、ives through sustaining memberships. The more than 7000 committee volunteers and the 2000 sustaining memberships together form CSAs total membership from which its Directors are chosen. Sustaining memberships represent a major source of income for CSAs standards development activities. The Associati
16、on offers certification and testing services in support of and as an extension to its standards development activities. To ensure the integrity of its certification process, the Association regularly and continually audits and inspects products that bear the CSA Mark. In addition to its head office
17、and laboratory complex in Etobicoke, CSA has regional branch offices in major centres across Canada and inspection and testing agencies in eight countries. Since 1919, the Association has developed the necessary expertise to meet its corporate mission: CSA is an independent service organization whos
18、e mission is to provide an open and effective forum for activities facilitating the exchange of goods and services through the use of standards, certification and related services to meet national and international needs. Four plus amples renseignernents sur les services de la CSA, sadresser B For f
19、urther information on CSA services, write to Association canadienne de normalisation * Canadian Standards Association 178, boulevard Rexdale 178 Rexdale Boulevard Etobicoke, Ontario, M9W 1R3 Canada Le Consell canadlen des normes est Iorganisme de coordination du Systbme de normes nationales, une fed
20、eration dorganismes independants et autonornes qui travaillent au dBveloppement et 2i Iam6lioration de la normalisation volontaire dans Iint6r8t national. Les principaux buts du Conseil sont dencourager et de promouvoir la normalisation volontaire cornme rnoyen dameliorer Idconomie nationale, darnel
21、iorer la sante, la s6curitb et le bien- cet aspect demeure la responsabilite de Iorganisme rddacteur de normes accredit cest pourquoi il est recommand6 aux utilisateurs de se procurer Ibdition la plus rbcente de la norme auprbs de Iorganisrne qui Ia prdparde. Une Norme nationale du Canada est une no
22、rme, approuvde par le Conseil canadien des normes, qui reflbte une entente raisonnable parrni les points de vue dun certain Lapprobation dune norme en tant que Norme nationale du Canada indique quelle est conforme aux mdthodes et critbres Btablis par le Conseil canadien des normes. 11 est recommand6
23、 aux personnes qui ont besoin de normes de se servir des Normes nationales du Canada lorsque la chose est possible. Ces normes font Iobjet dexamens The Standards Council of Canada is the coordinating body of the National Standards system, a federation of independent, autonomous organizations working
24、 towards the further development and improvement of voluntary standardization in the national interest. The principal objects of the Council are to foster and promote voluntary standardization as a means of advancing the national economy, benefiting the health, safety, and welfare of the public, ass
25、isting and protecting the consumer, facilitating domestic and international trade, and furthering international cooperation in the field of standards. A National Standard of Canada is a standard which has been approved by the Standards Council of Canada and one which reflects a reasonable agreement
26、among the views of a number of capable individuals whose collective interests provide to the greatest practicable extent a balance of representation of producers, users, consumers, and others with relevant interests, as may be appropriate lo the subject in hand. It normally is a standard which is ca
27、pable of making a significanl and timely contribution to the national interest. Approval of a standard as a National Standard of Canada indicates that a standard conforms to the criteria and procedures established by the Standards Council of Canada. Approval does not refer lo the technical content o
28、f the standard; this remains the continuing responsibility of the accredited standards-development organization. Those who have a need to apply standards are encouraged to use National Standards of Canada whenever practicable. These standards are subject to periodic review; therefore, users are caut
29、ioned to obtain the latest edition from the organization preparing the standard. La responsabilite dapprouver les Norrnes nationales du Canada incombe au . The responsibility for approving National Standards of Canada rests with the Conseil canadien des normes Standards Council of Canada 45, rue OCo
30、nnor, Bureau 1200 * 45 OConnor Street, Suite 1200 Ottawa, Ontario, KIP 6N7 Canada Ben que le but premier visd par cette norme soit dnoncd sous sa rubrique Domaine dapplication, il esf important de retenir quil incornbe A iufilisateur de juger si la norme convient Ci ses besoins particuliers. Althoug
31、h the intended primary applicafion of this Standard is stated in its Scope, it is important to note that it remains the responsibility of the user to judge its suitability for their particular purpose. lnformation technology - Protocol for providing the connectionless-mode network service: Provision
32、 of the undedyinq service by on X.25 subnetwork CAN/CSA-iSO/EC 8473-3-97 CA N/CSA -ISO/IE C 84 73 - 3-97 Information technology - Protocol for providing the connectionless-mode network service: Provision of the underlying service by an X.25 subnetwork CSA Preface Standards development within the Inf
33、ormation Technology sector is harmonized with international standards development. Through the CSA Technical Committee on Information Technology (TCIT), Canadians serve as the Canadian Advisory Committee (CAC) on ISO/IEC Joint Technical Committee 7 on Information Technology (ISO/IEC JTC1) for the St
34、andards Council of Canada (SCC), the IS0 member body for Canada and sponsor of the Canadian National Committee of the IEC. Also, as a member of the International Telecommunication Union (ITU), Canada participates in the International Telegraph and Telephone Consultative committee (ITU-T). This Inter
35、national Standard was reviewed by the CSA TCIT under the jurisdiction of the Strategic Steering Committee on Information Technology and deemed acceptable for use in Canada. (A committee membership list is available on request from the CSA Committee Administrator.) From time to time, lSO/IEC may publ
36、ish addenda, corrigenda, etc. The CSA TCIT will review these documents for approval and publication. For a listing, refer to the CSA Information Products Catalogue or CSA Info Update or contact a CSA Sales representative. This Standard has been formally approved, without modification, by these Commi
37、ttees and has been approved as a National Standard of Canada by the Standards Council of Canada. February 1997 0 Canadian Standards Association - 7 997. All rights reserved. No part of this publication may be reproduced in any form, in un electronic retrieval system or otherwise, without the prior p
38、ermission of the publisher. /SO/IEC material is reprinted with the permission of the publisher. February 1997 CSA/1 I NTER NAT IO NAL STANDARD ISO/IEC 8473-3 First edition 1995-03-1 5 Information technology - Protocol for providing the connectionless-mode network service: Provision of the underlying
39、 service by an X.25 subnetwork Technologies de /information - Protocole de fourniture du service de reseau en mode sans connexion: Fourniture du service socls-jacent par un sous-reseau X.25 Reference number lSO/lEC 8473-311 995(E) ISOfiEC 8473-3: 1995(E) Contents 1 Scope 2 Normative references . 2.1
40、 Identical Recommendations I International Standards 2.2 Paired Recommendations I International Standards identical in technical content . 2.3 Additional references 3 Definitions 3.1 Reference model definitions . 3.2 Network layer architecture definitions 3.3 Network layer addressing definitions . 3
41、.4 X.25 definitions . 4 Abbreviations . 5 Subnetwork dependent convergence function 5.1 General model . 5.2 Subnetwork user data 5.3 Subnetwork dependent convergence functions used with X.25 subnetworks Annex A . PICS proforma A . i Introduction . A.2 A.3 A.4 Identification . AS Abbreviations and sp
42、ecial symbols . Instructions for completing the PICS proforma Subnetwork dependent convergence functions for use with X.25 subnetworks . Page 1 i 1 1 P 2 2 2 2 2 2 3 3 3 3 7 7 7 7 9 10 0 ISO/IEC 1995 All rights reserked . Unless otherwise specified. no part of this publication may be reproduced or u
43、tilized in any form or by any means. electronic or mechanical. including photocopying and microfilm. without permission in writing from the publisher . ISO/IEC Copyright Office Case postale 56 CH-1211 Genkve 20 Switzerland ii 0 ISOflEC ISO/IEC 8473-3: 1945(E) Foreword IS0 (the International Organiza
44、tion for Standardization) and IEC (the Inter- national Electrotechnical Commission) form the specialized system for worldwide standardization. National bodies that are members of IS0 or IEC participate in the development of International Standards through technical committees established by the resp
45、ective organization to deal with particular fields of technical activity. IS0 and IEC technical committees collaborate in fields of mutual interest. Other international organizations, governmental and non-governmental, in liaison with IS0 and IEC, also take part in the work. In the field of informat
46、ion technology, IS0 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 bo
47、dies casting a vote. International Standard ISO/IEC 8473-3 was prepared by Joint Technical Corn- mittee ISO/IEC JTC 1, Information technology, Subcommittee SC 6, Telecom- munications and information exchange between systems, in collaboration with ITU-T. The identical text is published as ITU-T Recom
48、mendation X.622. ISO/IEC 8473 consists of the following parts, under the general title Information technology - Protocol for providing the connectionless-mode network service: - Part I: Protocol specification - Part 2: Provision of the underlying service by un ISO/IEC 8802 subnetwork - Parr 3: Provi
49、sion of rhe underlying service by an X.25 subnetwork - Part 4.- Provision of the underlying service by a subnetwork thar provides the OSi data link sewice Annex A forms an integral part of this part of ISO/IEC 8473 . 111 ISO/IEC 8473-3: 1995(E) 0 ISOAEC Introduction This is one of a set of Recommendations and International Standards produced to facilitate the interconnection of open systems. The set covers the services and protocols required to achieve such interconnection. This Recommendation I International Standard is positioned w
