1、 National Standard of CanadaCAN/CSA-ISO/IEC 8473-5-01(ISO/IEC 8473-5:1997)International Standard ISO/IEC 8473-5:1997 (first edition, 1997-05-01), has been adopted withoutmodification (IDT) as CSA Standard CAN/CSA-ISO/IEC 8473-5-01, which has been approved as a NationalStandard of Canada by the Stand
2、ards Council of Canada.ISBN 1-55324-408-7 December 2001Reference numberISO/IEC 8473-5:1997(E)The 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 chartere
3、d in 1919 and accredited by a federation of independent, autonomousthe Standards Council of Canada 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 standar
4、dization in the national interest.engaged in standards development and certification The principal 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 theproducer
5、s and users including manufacturers, health, safety, and welfare of the public, assisting consumers, retailers, unions and professional and protecting the consumer, facilitating domestic organizations, and governmental agencies. The and international trade, and furthering internationalstandards are
6、used widely by industry and commerce cooperation in the field of standards.and often adopted by municipal, provincial, and A National Standard of Canada is a standard whichfederal governments in their regulations, particularly in has been approved by the Standards Council ofthe fields of health, saf
7、ety, building and construction, Canada and one which reflects a reasonableand the environment. agreement 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 greates
8、t practicable extent a balance ofdevelopment by volunteering their time and skills to representation of producers, users, consumers, andCSA Committee work and supporting the Associations others with relevant interests, as may be appropriateobjectives through sustaining memberships. The more to the s
9、ubject in hand. It normally is a standardthan 7000 committee volunteers and the 2000 which is capable 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 Na
10、tional Standard ofSustaining memberships represent a major source of Canada indicates that a standard 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
11、 not refer to theservices in support of and as an extension to its technical content of the standard; this remains thestandards development activities. To ensure the continuing responsibility of the accreditedintegrity of its certification process, the Association standards-development organization.
12、regularly and continually audits and inspects products Those who have a need to apply standards 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 regiona
13、l branch offices in major to periodic review; therefore, users are cautioned centres across Canada 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
14、 responsibility for approving National Standards meet its corporate mission: CSA is an independent 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 g
15、oods and services through the use of Ottawa, Ontario, K1P 6N7standards, certification and related services to meet Canadanational and international needs.For further information on CSA services, write toCanadian Standards Association178 Rexdale BoulevardToronto, Ontario, M9W 1R3CanadaLes normes nati
16、onales du Canada sont publies en versions franaise et anglaise.Although the intended primary application of this Standard is stated in its Scope, it is importantto note that it remains the responsibility of the users to judge its suitability for their particular purpose.Registered trade-mark of Cana
17、dian Standards AssociationInformation technology Protocol for providing the connectionless-mode networkCAN/CSA-ISO/IEC 8473-5-01 service: Provision of the underlying service by ISDN circuit-switched B-channelsDecember 2001 Canadian Standards Association CSA/1CAN/CSA-ISO/IEC 8473-5-01Information tech
18、nology Protocolfor providing the connectionless-mode network service: Provision ofthe underlying service by ISDNcircuit-switched B-channelsCSA PrefaceStandards development within the Information Technology sector is harmonized with internationalstandards development. Through the CSA Technical Commit
19、tee 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 Committee of the
20、IEC. Also, as a member of theInternational Telecommunication Union (ITU), Canada participates in the International Telegraph andTelephone Consultative Committee (ITU-T).This International Standard was reviewed by the CSA TCIT under the jurisdiction of the StrategicSteering Committee on Information T
21、echnology 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 TCIT will review these documents for approvaland publication. For a listing, refer to the CSA
22、Information Products catalogue or CSA Info Update orcontact a CSA Sales representative. This Standard has been formally approved, without modification, bythese Committees and has been approved as a National Standard of Canada by the Standards Council ofCanada.December 2001 Canadian Standards Associa
23、tion 2001All rights reserved. No part of this publication may be reproduced in any form whatsoever without the prior permissionof the publisher. ISO/IEC material is reprinted with permission. Where the words “this International Standard” appearin the text, they should be interpreted as “this Nationa
24、l Standard of Canada”. Inquiries regarding this National Standard of Canada should be addressed to Canadian Standards Association 178 Rexdale Boulevard, Toronto, Ontario, Canada M9W 1R31-800-463-6727 416-747-4044www.csa.caINTERNATIONAL STANDARD ISO/IEC 8473-5 First edition 1997-05-01 Information tec
25、hnology - Protocol for providing the connectionless-mode network service: Provision of the underlying service by ISDN circuit-switched B-channels Technologies de Iinforma tion - Protocole pour la fourniture du service de r b) Network layer; C) service; d) service data unit; e) protocol control infor
26、mation. 32 . Network layer architecture definitions This Recommendation I International Standard makes use of the following terms defined in ISO/IEC 8648: a subnetwork; b) subnetwork dependent convergence protocol; C subnetwork dependent convergence function; d) subnetwork access protocol. 33 . Netw
27、ork layer addressing definitions This Recommendation I International Standard makes use of the following term defined in CCITT Rec. X.213 I ISO/IEC 8348: - subnetwork point of attachment. 4 Abbreviations For the purposes of this Recommendation I International Standard, the following abbreviations ap
28、ply: CLNP Connectionless-mode Network Protocol DCE Data Circuit-terminating Equipment DTE Data Terminal Equipment ES End System IS Intermediate System 2 ITU-T Rec. 1 FL.625 (1996 E) A ISO/IEC 8473-5 : 1997 (E) ISDN PDU PVC QOS SDU SN SNDCF SNDCP SNICP SNAcP SNPA SNCR SNSDU TA TE Integrated Services
29、Digital Network Protocol Data Unit Permanent Virtual Circuit Quality of Service Service Data Unit Subnetwork Subnetwork Dependent Convergence Function Subnetwork Dependent Convergence Protocol Subnetwork Independent Convergence Protocol Subnetwork Access Protocol Subnetwork Point of Attachment Subne
30、twork Connection Reference Subnetwork Service Data Unit Terminal Adapter Terminal Equipment 5 Subnetwork dependent convergence function 51 . General model The general model for providing the underlying service assumed by the protocol in conjunction with a real subnetwork that uses a connectionless s
31、ubnetwork access protocol is as follows. The generation of an SN-UNIT-DATA Request by the CLNP results in the generation of a corresponding subnetwork-specific UN IT-DATA request by the subnetwork dependent convergence function. The receipt of a subnetwork-specific UN IT-DATA indication associated w
32、ith delivery of a connectionless data unit to its destination causes the SNDCF to generate an SN-UNIT-DATA indication to the CLNP. The general model for providing the underlying service assumed by the CLNP in conjunction with a real subnetwork that uses a connection-mode subnetwork access protocol i
33、s as follows. The generation of an SN-UNIT-DATA request by the CLNP causes a connection (logical channel, logical link, or the equivalent) to be made available for the transmission of SN-User-data. If a connection cannot be made available, the SN-UNIT-DATA Request is discarded. The receipt of subnet
34、work-specific PDUs containing SN-User-data causes the SNDCF to generate an SN-UNIT-DATA indication to the CLNP. Where a real subnetwork is designed to use either a connectionless-mode or a connection-mode subnetwork access protocol, the provision of the underlying service assumed by the CLNP is achi
35、eved by using the connectionless-mode alternative. 52 . Subnetwork user data The SN-Userdata is an ordered multiple of octets, and is transferred transparently between the specified subnetwork points of attachment. The underlying service assumed by the CLNP is required to support a service data unit
36、 size of at least 5 12 octets. If the minimum service data unit sizes supported by all of the subnetworks involved in the transmission of a particular PDU are known to be large enough that segmentation is not required, then either the full protocol or the non-segmenting protocol subset may be used.
37、Data received from a subnetwork with protocol identification specifying this protocol (see ITU-T Rec. X.233 I ISO/IEC 8473-l) shall be processed according to this Recommendation I International Standard. NOTE - Data with other protocol identification should be ignored, since it may have been sent by
38、 an implementation supporting additional protocols intended for use with this protocol. ITU-T Rec. X.625 (1996 E) 3 ISO/IEC 8473-5 : 1997 (E) 53 . Subnetwork dependent convergence functions used with ISDN circuit-switched B-channel 5.3.1 The ISDN environment This SNDCF applies when an ISDN B-channel
39、 is used to carry the PDUs as defined in ITU-T Rec. X.233 1 ISO/IEC 8473-1 between systems. In this context a system may be either an End System (ES) or an Intermediate System (IS), as shown in Figure 1. The underlying ISDN service is the 64 kbit/s bearer service as described in Recommendation I.23
40、1. NOTE - The use of more than one B-channel between a pair of systems is not precluded. When more than one B-channel is used, the single link procedures of ISOiIEC 7776 shall be used on each. ES/IS ES/IS TIS07740-96ldOl Figure 1 - ES-to-IS, IS-to-IS, or ES-to-ES directly connected via ISDN Once the
41、 B-channel has been established (see 5.3.2.2 or 5.3.2.3) the requirements of ITU-T Rec. X.623 1 ISO/IEC 8473-4 shall be applied, i.e. the SNDCF for operation over a subnetwork which provides the OS1 Data Link service. The ES or IS may be either a TEl or TE2/TA terminal supporting the ISDN B-channel
42、presenting the protocol stacks at the S- or T- reference point in accordance with the Recommendations and International Standards shown in Figure 2. I Network ISOAEC 8473-l SNDCF for ISDN 4 Q.921 ISOAEC 11575 (Use of ISOAEC 7776 to provide the DL service) ISOAEC 7776 D-channel I .430 or B-channel 1.
43、431 This Recommendation 1 International Standard lTIS07750-96/d02 Figure 2 - Protocol layers at S- and T-reference points 4 ITU-T Rec. X.625 (1996 E) ISO/IEC 8473-5 : 1997 (E) 5.3.2 Procedures for a TEl or TE2/TA This subclause covers the use of semi-permanent or demand access B-channel connections
44、that can be available to the TEl or TE2/TA terminals. NOTE - The use of the D-channel to operate the CLNP is outside the scope of this Recommendation 1 International Standard. The mapping of elements of the CLNS to the protocol and procedures of ISO/IEC 8473 is specified in CCITT Rec. X. 213 1 ISO/I
45、EC 8348. The following subclauses specie the provision required in addition to these mappings by systems attached to the S/T reference points. 5.3.2.1 Additional procedures for a TEl or TE2/TA when using the ISDN B-channel to directly connect to a remote terminal. The ES or IS shall implement at the
46、 S/T reference points the protocol stacks shown in Figure 2. One of the stacks is used to support signalling necessary to establish the ISDN circuit switched connection to the remote terminal, and the other is used to support the CLNP itself. At the physical layer, Recommendation 1.430 shall be used
47、 if the access is via the basic rate interface, and Recommendation I.43 1 shall be used if the access is via the primary rate interface. At the data link layer, Recommendation 4.921 shall be used over the D-channel and ISO/IEC 7776 shall be used over the B-channel after it has been established. At t
48、he network layer, Recommendation Q.93 1 shall be used over the D-channel to convey signalling information to the ISDN for the purposes of ISDN connection establishment, and ISO/IEC 8473 shall be used over the B-channel for information transfer. 5.3.2.2 Semi-permanent B-channel connection ISO/IEC 777
49、6 shall be used in accordance with ISO/IEC 11575 to provide the OS1 Connection-mode Data Link Service. This service may be used either: a) in accordance with ITU-T Rec. X.623 1 ISO/IEC 8473-4 to provide the ISO/IEC 8473 underlying service; or b) in accordance with ISO/IEC 8208 to operate the X.25 packet layer protocol. In this case the ISO/IEC 8473 underlying service shall be provided in accordance with ITU-T Rec
