1、Reference numberISO/IEC 8208:2000(E)ISO/IEC 2000Information technology Datacommunications X.25 Packet LayerProtocol for Data Terminal EquipmentTechnologies de linformation Communication de donnes Protocole X.25 de couche paquet pour terminal de donnesNational Standard of CanadaCAN/CSA-ISO/IEC 8208:0
2、2(ISO/IEC 8208:2000)International Standard ISO/IEC 8208:2000 (fourth edition, 2000-11-01) has been adopted withoutmodification (IDT) as CSA Standard CAN/CSA-ISO/IEC 8208:02, which has been approved as a National Standardof Canada by the Standards Council of Canada.ISBN 1-55324-918-6 December 2002The
3、 Canadian Standards Association (CSA), The Standards Council of Canada is theunder whose auspices this National Standard has been coordinating body of the National Standards system, produced, was chartered in 1919 and accredited by a federation of independent, autonomousthe Standards Council of Cana
4、da to the National organizations working towards the furtherStandards system in 1973. It is a not-for-profit, development and improvement of voluntarynonstatutory, voluntary membership association standardization in the national interest.engaged in standards development and certification The princip
5、al objects of the Council are to foster activities. and promote voluntary standardization as a means CSA standards reflect a national consensus of of advancing the national economy, benefiting theproducers and users including manufacturers, health, safety, and welfare of the public, assisting consum
6、ers, retailers, unions and professional and protecting the consumer, facilitating domestic organizations, and governmental agencies. The and international trade, and furthering internationalstandards are used widely by industry and commerce cooperation in the field of standards.and often adopted by
7、municipal, provincial, and A National Standard of Canada is a standard whichfederal governments in their regulations, particularly has been approved by the Standards Council ofin the fields of health, safety, building and Canada and one which reflects a reasonableconstruction, and the environment. a
8、greement among the views of a number of capableIndividuals, companies, and associations across individuals whose collective interests provide to theCanada indicate their support for CSAs standards greatest practicable extent a balance ofdevelopment by volunteering their time and skills to representa
9、tion of producers, users, consumers, andCSA Committee work and supporting the Associations others with relevant interests, as may be appropriateobjectives through sustaining memberships. The to the subject in hand. It normally is a standardmore than 7000 committee volunteers and the 2000 which is ca
10、pable of making a significant and timelysustaining memberships together form CSAs total contribution to the national interest.membership from which its Directors are chosen. Approval of a standard as a National Standard ofSustaining memberships represent a major source of Canada indicates that a sta
11、ndard conforms to theincome for CSAs standards development activities. criteria and procedures established by the StandardsThe Association offers certification and testing Council of Canada. Approval does not refer to theservices in support of and as an extension to its technical content of the stan
12、dard; this remains thestandards development activities. To ensure the continuing responsibility of the accreditedintegrity of its certification process, the Association standards-development organization.regularly and continually audits and inspects products Those who have a need to apply standards
13、arethat bear the CSA Mark. encouraged to use National Standards of CanadaIn addition to its head office and laboratory complex whenever practicable. These standards are subject in Toronto, CSA has regional branch offices in major to periodic review; therefore, users are cautioned centres across Cana
14、da and inspection and testing to obtain the latest edition from the organizationagencies in eight countries. Since 1919, the preparing the standard.Association has developed the necessary expertise to The responsibility for approving National Standards meet its corporate mission: CSA is an independe
15、nt of Canada rests with theservice organization whose mission is to provide an Standards Council of Canadaopen and effective forum for activities facilitating the 270 Albert Street, Suite 200exchange of goods and services through the use of Ottawa, Ontario, K1P 6N7standards, certification and relate
16、d services to meet Canadanational and international needs.For further information on CSA services, write toCanadian Standards Association5060 Spectrum Way, Suite 100Mississauga, Ontario, L4W 5N6CanadaAlthough the intended primary application of this Standard is stated in its Scope, it is importantto
17、 note that it remains the responsibility of the users to judge its suitability for their particular purpose.Registered trade-mark of Canadian Standards AssociationCAN/CSA-ISO/IEC 8208:02 Packet Layer Protocol for Data Terminal EquipmentInformation technology Data communications X.25December 2002 Can
18、adian Standards Association CSA/1CAN/CSA-ISO/IEC 8208:02Information technology Datacommunications X.25 PacketLayer Protocol for Data TerminalEquipmentCSA PrefaceStandards development within the Information Technology sector is harmonized with internationalstandards development. Through the CSA Techn
19、ical Committee on Information Technology (TCIT),Canadians serve as the Canadian Advisory Committee (CAC) on ISO/IEC Joint Technical Committee 1 onInformation Technology (ISO/IEC JTC1) for the Standards Council of Canada (SCC), the ISO memberbody for Canada and sponsor of the Canadian National Commit
20、tee of the IEC. Also, as a member of theInternational Telecommunication Union (ITU), Canada participates in the International Telegraph andTelephone Consultative Committee (ITU-T).This Standard supersedes CAN/CSA-ISO/IEC 8208-96 (adoption of ISO/IEC 8208:1995).This International Standard was reviewe
21、d by the CSA TCIT under the jurisdiction of the StrategicSteering Committee on Information Technology and deemed acceptable for use in Canada. (Acommittee membership list is available on request from the CSA Project Manager.) From time to time,ISO/IEC may publish addenda, corrigenda, etc. The CSA TC
22、IT will review these documents for approvaland publication. For a listing, refer to the CSA Information Products catalogue or CSA Info Update orcontact a CSA Sales representative. This Standard has been formally approved, without modification, bythe Technical Committee and has been approved as a Nat
23、ional Standard of Canada by the StandardsCouncil of Canada.December 2002 Canadian Standards Association 2002All rights reserved. No part of this publication may be reproduced in any form whatsoever without the priorpermission of the publisher. ISO/IEC material is reprinted with permission. Where the
24、 words “thisInternational Standard” appear in the text, they should be interpreted as “this National Standard ofCanada”. Inquiries regarding this National Standard of Canada should be addressed to Canadian Standards Association 5060 Spectrum Way, Suite 100, Mississauga, Ontario, Canada L4W 5N6 1-800
25、-463-6727 416-747-4044www.csa.caReference numberISO/IEC 8208:2000(E)ISO/IEC 2000INTERNATIONALSTANDARDISO/IEC8208Fourth edition2000-11-01Information technology Datacommunications X.25 Packet LayerProtocol for Data Terminal EquipmentTechnologies de linformation Communication de donnes Protocole X.25 d
26、e couche paquet pour terminal de donnesISO/IEC 8208:2000(E)PDF disclaimerThis PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be printed or viewed but shall notbe edited unless the typefaces which are embedded are licensed to and installed on the co
27、mputer performing the editing. In downloading thisfile, parties accept therein the responsibility of not infringing Adobes licensing policy. The ISO Central Secretariat accepts no liability in thisarea.Adobe is a trademark of Adobe Systems Incorporated.Details of the software products used to create
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29、tral Secretariat at the address given below. ISO/IEC 2000All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronicor mechanical, including photocopying and microfilm, without permission in writing from either IS
30、O at the address below or ISOs member bodyin the country of the requester.ISO copyright officeCase postale 56 Gb7 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.chWeb www.iso.chii ISO/IEC 2000 All rights reservedISO/IEC 8208 : 2000(E)iii ISO/IEC 2000 All rights reser
31、vedCONTENTSPageForewordvi1 Scope 12 Normative references 12.1 Identical Recommendations | International Standards .12.2 Paired Recommendations | International Standards equivalent in technical content22.3 Additional references .23 General considerations .23.1 Compatibility with versions of Recommend
32、ation X.25 .33.2 Environments.53.3 Differences in DTE/DTE and DTE/DCE operation.53.4 Operation over circuit-switched connections.63.5 Provision of the OSI Network Service.73.6 External Packet Layer interactions.73.7 Logical channels 73.8 Packet Layer entity.83.9 Packet types .93.10 Procedures for in
33、itialization.94 Procedures for restart.94.1 Originating a restart request.104.2 Receiving a restart indication.124.3 Restart collision .124.4 Restart confirmation. 124.5 Determining “DTE” or “DCE” characteristics.125 Procedures for Virtual Call setup and clearing 135.1 Ready state.135.2 Procedures f
34、or Virtual Call setup.135.3 Rejecting a call.155.4 Aborting a call request.155.5 Procedures for Virtual Call clearing 156 Procedures for data and interrupt transfer.166.1 States for data and interrupt transfer 176.2 Maximum User Data Field length of DATA packets .176.3 Delivery Confirmation bit176.4
35、 More Data mark . 186.5 Complete packet sequence .186.6 Qualifier bit186.7 Fragmentation and reassembly of messages.196.8 Procedures for interrupt .206.9 Transit delay of DATA packets217 Procedures for flow control217.1 Flow control.227.2 Throughput characteristics and throughput classes25ISO/IEC 82
36、08 : 2000(E) ISO/IEC 2000 All rights reservediv8 Procedures for reset . . 258.1 Originating a reset request .278.2 Receiving a reset indication. 278.3 Reset collision 278.4 Reset confirmation. 279 Effects of clear, reset, and restart procedures on the transfer of packets . 2710 Effects of Layers 1 a
37、nd 2 on the Packet Layer 2811 Error handling 2811.1 The DIAGNOSTIC packet. 2911.2 Nonreceipt of window-rotation information 2911.3 Receipt of erroneous DATA packets . 3012 Packet formats. 3112.1 General. 3112.2 Call setup and call clearing packets . 3312.3 DATA and interrupt packets 4212.4 Flow cont
38、rol packets 4412.5 Reset packets . 4512.6 Restart packets . 4712.7 DIAGNOSTIC packet 4812.8 REJECT packet 4912.9 Registration packets. 5013 Procedures for optional user facilities . 5213.1 On-line Facility Registration 5213.2 Extended and Super Extended Packet Sequence Numbering 5913.3 D-bit Modific
39、ation. 6013.4 Packet Retransmission . 6013.5 Incoming Calls Barred . 6113.6 Outgoing Calls Barred . 6113.7 One-way Logical Channel Outgoing 6113.8 One-way Logical Channel Incoming . 6113.9 Nonstandard Default Packet Sizes . 6113.10 Nonstandard Default Window Sizes 6113.11 Default Throughput Classes
40、Assignment. 6213.12 Flow Control Parameter Negotiation . 6213.13 Throughput Class Negotiation Facilities 6313.14 Closed User Group related facilities 6413.15 Bilateral Closed User Group related facilities 6813.16 Fast Select 6913.17 Fast Select Acceptance 7013.18 Reverse Charging. 7013.19 Reverse Ch
41、arging Acceptance . 7013.20 Local Charging Prevention 7013.21 Network User Identification (NUI) related facilities 7113.22 Charging Information.7113.23 ROA related facilities 7313.24 Hunt Group 7313.25 Call Redirection and Call Deflection related facilities. 7313.26 Called Line Address Modified Noti
42、fication. 7613.27 Transit Delay Selection and Indication 7613.28 Alternative Addressing Related Facilities 7613.29 TOA/NPI address subscription 7813.30 Reference Number . 7814 Procedures for optional ITU-T specified DTE facilities.8014.1 Calling Address Extension. 8014.2 Called Address Extension 801
43、4.3 Minimum Throughput Class Negotiation 8014.4 End-to-End Transit Delay Negotiation 81ISO/IEC 8208 : 2000(E)v ISO/IEC 2000 All rights reserved14.5 Priority.8114.6 Protection.8114.7 Expedited Data Negotiation.8115 Format for Facility Field in call setup/clearing packets .8215.1 General.8215.2 Coding
44、 of the Facility Field for optional user facilities .8315.3 Coding of the Facility Field for ITU-T specified DTE facilities8916 Format for Registration Field in registration packets9216.1 General.9216.2 Coding of the Registration Field for registration-facilities 9317 Diagnostic codes 9518 Timers an
45、d retransmission counts .10119 State diagrams.10520 State tables.11121 Conformance .12021.1 Static conformance.12021.2 Protocol Implementation Conformance Statement 12021.3 Dynamic conformance .120AnnexesA Private networks.123B PICS Proforma .131C Differences between various editions of ISO/IEC 8208
46、.159D Abbreviations169ISO/IEC 8208 : 2000(E) ISO/IEC 2000 All rights reservedviForewordISO (the International Organization for Standardization) and IEC (the InternationalElectrotechnical Commission) form the specialized system for worldwide standardization.National bodies that are members of ISO or
47、IEC participate in the development ofInternational Standards through technical committees established by the respectiveorganization to deal with particular fields of technical activity. ISO and IEC technicalcommittees collaborate in fields of mutual interest. Other international organizations,govern
48、mental and non-governmental, in liaison with ISO and IEC, also take part in thework.International Standards are drafted in accordance with the rules given in the ISO/IECDirectives, Part 3.In the field of information technology, ISO and IEC have established a joint technicalcommittee, ISO/IEC JTC 1.
49、Draft International Standards adopted by the joint technicalcommittee are circulated to national bodies for voting. Publication as an InternationalStandard requires approval by at least 75 % of the national bodies casting a vote.Attention is drawn to the possibility that some of the elements of this InternationalStandard may be the subject of patent rights. ISO and IEC shall not be held responsiblefor identifying any or all such patent rights.International Standard ISO/IEC 8208 was prepared by Joint Technical CommitteeISO
