1、CCITT RECMN*X-b10 92 4862593 0580323 171 INTERNATIONAL TELECOMMUNICATION UN ION CCITT THE INTERNATIONAL TELEGRAPH AND TELEPHONE CON SU LTATI VE COM M ITTE E DATA COMMUNICATION NETWORKS X.61 O (09/92) PROVISION AND SUPPORT NETWORK SERVICE OF THE OS1 CONNECTION-MODE Recommendation X.61 O CCITT RECMN*X
2、=bLO 92 Y8b2591 0580124 008 W FOREWORD The CCITT (the International Telegraph and Telephone Consultative Committee) is a permanent organ of the International Telecommunication Union (ITLJ). CCITT is responsible for studying technical, operating and tariff questions and issuing Recommendations on the
3、m with a view to standardizing telecommunications on a worldwide basis. The Plenary Assembly of CCIiT which meets every four years, establishes the topics for study and approves Recommendations prepared by its Study Groups. The approval of Recommendations by the members of CCITT between Plenary Asse
4、mblies is covered by the procedure laid down in CCITT Resolution No. 2 (Melbourne, 1988). Recommendation X.610 was prepared by Study Group VI1 and was approved under the Resolution No. 2 procedure on the 10th of September 1992. CCIT NOTE In this Recommendation, the expression “Administration” is use
5、d for conciseness to indicate both a telecommunication administration and a recognized private operating agency. O ITU 1993 All righrs reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, with
6、out permission in writing from the ITU. CCITT RECMN*X=b30 92 = 48b2593 0580325 T44 CONTENTS Page 1 Scope . 1 2 References . 2 3 Definitions . 3 4 Abbreviations 4 5 Pnnciples and framework for describing the support of the OS1 connection-mode network service . 4 6 Protocol combinations for the suppor
7、t of CONS 9 Recommendation X.610 (09192) 1 CCITT RECMNUXmhLO 72 = 4862591 058012b 960 INTRODUCTION 1 1 This Recommendation is one of a set of Recommendations produced to provide a high level architectural overview of the provision and support of the OS1 Connection-mode Network Service that is define
8、d in Recommendation X.213. Other Recommendations in the X.610-Series deal with specific cases for providing the Connection-mode Network Service. In some layers of the OS1 Reference Model Architecture, it is possible to refer to a single layer protocol specification as the place in which ail informat
9、ion necessary to understand how to provide the layer service can be found. This is not possible in the Network Layer since the number of different subnetwork technologies and interconnection strategies that must be accommodated is quite large. It is the intention of this Recommendation, therefore, t
10、o serve as a single point of reference for information concerning the ways in which Network Layer protocols can be used to provide the OS1 Connection-mode Network Service in various environments. This Recommendation describes the specifics for the provision and support of the OS1 Connection-mode Net
11、work Service and the criteria for the inclusion of protocol combinations. It also describes the applicability of particular Network Layer protocol Recommendations to the provision and support of the Connection-mode Network Service. I 11 Recommendation X.610 (09/92) CCITT RECNN*X=bLO 92 4862593 OSBOL
12、27 817 Recommendation X.610 PROVISION AND SUPPORT OF THE OS1 CONNECTION-MODE NETWORK SERVICE (1 992) The CCITT, considering (a) that Recommendation X.200 defines the Reference Model of Open Systems Interconnection (OSI) for CCITT Applications; (b) that Recommendation X.210 specifies the OS1 Layer Se
13、rvice Definition Conventions for describing the services of the layers of OS1 Reference Model; (c) that Recommendation X.213 specifies the Network Service Definition for Open Systems Interconnection for CCIT Applications; (d) that there exists a number of different network technologies (e.g. CSDN, I
14、SDN, PSDN, PSTN) to support data transmission; (e) that there is a need to specify the provision and support of the OS1 Connection-mode Network Service in a unified fashion taking into account the various environments, unanimously declares the view that the architectural principles and framework and
15、 the protocol combinations contained within this Recommendation shall form he basis for the provision and support of the OS1 Connection-mode Network Service. This Recommendation provides an architectural overview of the OS1 Connection-mode Network Service defined in Recommendation X.213. This Recomm
16、endation a) provides a general overview; b) refers to those Recommendations which govern the provision of the Connection-mode Network Service; c) defines terms which may be used in specifying the environments in which protocol combinations operate; d) specifies principles and a framework for describ
17、ing the support of the OS1 Connection mode Network Service: e) considers the rationale for the inclusion of protocol combinations in the other Recommendations in the X.6 10-Series. Where a protocol combination does not support the OS1 Connection-mode Network Service, it lies outside the scope of thi
18、s Recommendation. Note - The scope of this Recommendation only includes protocol combinations where ail the mandatory (and inherent) elements of the OS1 Connection-mode Network-Service as specified in Recommendation X.213 are fully supported. Recommendation X.610 (09/92) 1 CCITT RECMN*X*bLO 92 48625
19、91 0580328 753 2 References - Recommendation 1.430, Basic User-Network Interface - Layer I Specification. - Recommendation 1.43 1, Primary Rate User-Network Interface - Layer I Specification. - Recommendation Q.921, ISDN User-Network Interface Data Link Layer Specification. - Recommendation Q.931, I
20、SDN User-Network Interface Layer 3 Specification for Basic Call Control. - Recommendation V.25, Automatic answering equipment andor parallel automatic calling equipment on the General Switched Telephone Network including procedures for disabling of echo control devices for both manually and automati
21、cally established calls. - Recommendation V.25 bis, Automatic calling and/or answering equipment on the General Switched Telephone Network (GSTN) using the IOO-Series interchange circuits. - Recommendation X.21, Inteface between Data Terminal Equipment (DTE) and Data Circuit- terminating Equipment D
22、CE) for Synchronous Operation on Public Data Networks. - Recommendation X.21 bis, Use on Public Data Networks of Data Terminal Equipment (DTE) which is designed for interfacing to Synchronous V-Series Modems. - Recommendation X.25, Interface between Data Terminal Equipment DTE) and Data Circuit- ter
23、minating Equipment (DCE) for terminals operating in the Packet Mode and connected to Public Data Networks by dedicated circuit. - Recommendation X.32, InterJaCe between Data Terminal Equipment (DTE) and Data Circuit- terminating Equipment (DCE) for terminals Operating in the packet mode and connecte
24、d to a Packet Switched Public Data Network through a Public Switched Telephone Network or an Integrated Services Digital Network or a Circuit Switched Public Data Network, - Recommendation X.75, Packet-Switched Signalling System between Public Networks providing Data Transmission Services. - Recomme
25、ndation X.200, Reference Model of Open Systems Interconnection for CCIIT applications. - IS0 7498, Information Processing Systems - Open Systems Interconnection - Basic Reference Model. - Recommendation X.210, OSI Layer Service definitions conventions. - IS0 TR 8509, Information Processing Systems -
26、 Open Systems Interconnection - Service conventions. - Recommendation X.213, Network Service Definition for Open Systems Interconnection for CCITT applications. - IS0 8348, Information Processing Systems - Data Communications - Network Service Definition - Addendum 2: Network Layer Addressing. - Rec
27、ommendation X.223, Use of Recommendation X.25 to provide the OS1 connection-mode network service for CCITT applications. - IS0 8878, Information Processing Systems - Data Communications - Use of Recommendation X.25 to provide the OSI Connection Mode Network Service. 2 Recommendation X.610 (09/92) CC
28、ITT RECMN*X=bLO 92 4862593 0580329 b9T - Recommendation X.305, Functionalities of subnetworks relating the support of the OSI Connection- mode Network Service. - Recommendation X.612, Provision of the OSI Connection-mode Network Service by Packet Mode Terminal Equipment connected to an Integrated Se
29、rvices Digital Network (ISDN) for CCIZT applications. - IS0 9514, Information Technology - Telecommunications and Information Exchange between Systems - Provision of the OSI Connection-mode Network Service by packet mode terminal equipment connected to an Integrated Services Digital Network (ISDN) -
30、 Addendum 1: Operation over an ISDN circuit- switched channel connecting directly to remote terminal. - Recommendation X.613, Use of X.25 Packet Layer Protocol in conjunction with Recommendations X.21 and X.21 bis to provide the OSI Connection-mode Network Service. ISOIiEC 10588, Information Technol
31、ogy - Data Communications - Use of X.25 Packet Layer Protocol in conjunction with Recommendations X.21 and X.21 bis to provide the OSI Connection-mode Network Service. - - Recommendation X.614, Use of X.25 Packet Layer Protocol to provide the OSI Connection-mode Network Service over the telephone ne
32、twork. - ISO/IEC 10732, Information Technology - Data Communications - Use of X.25 Packet Layer Protocol to provide the OSI Connection-mode Network Service over the Telephone Network. - IS0 7716, Information Processing Systems - Data Communications - Description of X.25 LAPB- compatible DTE Data Lin
33、k Procedures. - IS0 7776fCor. 1:1989, Information Processing Systems - Data communications - Description of X.25 LAPB-compatible DTE Data Link Procedures - Technical Corrigendum 1. - IS0 7716fCor. 2:1989, Information Processing Systems - Data communications - Description of X.25 LAPB-compatible DTE
34、Data Link Procedures - Technical Corrigendum 2. ISODEC 8208, Information Technology - Data communications - X.25 Packet iuyer Protocol for Data Terminal Equipment. ISO/IEC 8880-2, Information Technology - Data communications - Protocol combinations to provide and support the OSI Network Service - Pa
35、rt 2: Provision and support of the Connection mode Network Service, - Addendum I: Addition of the ISDN environment when a packet handling function is present - Addendum 2: Addition of PS“ and CSDN environments. - - - ISO/IEC 1oooO-2, Information Technology - Framework and tmnomy of International Sta
36、ndardized Profiles - Part 2: Taxonomy. 3 Deinitions This Recommendation is based on the concepts developed in Recommendation X.200 and makes use of the following terms defined in that Recommendation: a) Connection-mode; b) EndSystem; c) OS1 Network Layer; d) OS1 Network Service; e) OS1 Transport Lay
37、er; f) Protocol; g) Service. Recommendation X.610 (09/92) 3 CCITT RECMN*X=bLO 92 4862591 0580130 301 i Note - The use of the word “Network” to name the Network Layer of the OS1 Reference Model should be- distinguished from the use of the word “network” to denote a communications network as conventio
38、nally understood. Similarly, it is important to distinguish the specialized use of the term “Service” to refer to the abstract capability provided by one layer of the OS1 Reference Model to the layer above it from its use elsewhere to describe the provision of a “service” by an organization such as
39、an Administration. 4 Abbreviations I The following abbreviations are used in this Recommendation: CONS CSDN DCE DTE DTP ES IS ISDN NC m NS NSAP os1 PH PDU PLP PS PSDN PSTN STE Connection-mode Network Service Circuit Switched Data Network Data Circuit-terminating Equipment Data Terminal Equipment Dat
40、a Transfer Phase End System Intermediate System Integrated Services Digitai Network Network Connection Network Layer Network Service Network Service Access Point Open Systems Interconnection Packet Handler Protocol Data Unit Packet Layer Protocol Packet Switch Packet Switched Data Network Public Swi
41、tched Telephone Network Signalling Terminal Note - The terms CSDN, ISDN and PSDN and PSTN, as used in this Recommendation, can denote either a public or a private network. 5 Principles and framework for describing the support of the OS1 connection-mode network service The OS1 Network Service is the
42、Service provided by the Network Layer to the Transport Layer at the boundary between the Network and Transport Layer of the OS1 Reference Model as illustrated in Figure 1Bc.610. 4 Recommendation X.610 (09192) CCITT RECMNUX-630 72 1.1862573 0580131 248 W NS-provider - . uses sen/ice Transport protoco
43、l Transport Layer etwokerviie -+ . provi- servi. - Networkprotom4 =E- Network Layer FIGURE 1N.610 OS1 Network Service More specifically, the OS1 Network Service is the service provided between NSAPs in two OS1 end systems as illustrated in Figure 2Bc.610. OS1 end system OS1 end system OS1 Network Se
44、rvice , NSAP L I._._._._. - OS1 Network Service 4 3 FIGURE 2K.610 Provision of OS1 Network Senice The OS1 end systems may be either inside or outside a network as illustrated in Figure 3Bc.610. This could be the situation, for example, for a MHS node. Recommendation X.610 (09/92) 5 Physical represen
45、tation CCITT RECNNUX.6LO 92 I 4862593 0580132 LB4 Network _.- End system End system Logical representation Physical representation Logical representation End system IS IS a) End systems outside a network End system Network - End system system End system IS End system b) End system inside and outside
46、 a network Network Network Physical representation End system c) End systems inside networks FIGURE 31X.610 6 Recommendation X.610 (09192) CCITT RECflN+X.b10 92 48b253L 0580133 010 I There are two types of OS1 Network Service. This Recommendation is concerned with the support of the OSI Connection-m
47、ode Network Service (CONS). The involvement of networks in support of CONS depends upon the particular situation as illustrated in Figure 4X.610. In diagram a) of Figure 4Bc.610, the network protocols are not involved in conveying the CONS semantics between the end systems. This conveyance is done b
48、y means of the X.25 PLP which is carried transparently by the CSDN. In diagram b) of Figure 4K.610, the protocols of the CSDN are not involved but the protocols of the PSDN are involved. In diagram c) of Figure 4K.610, the packet protocols of the ISDN and PSDN convey all the semantics of CONS and no
49、 additional protocol is needed. Note - Recommendations X.25 and X.75 support the conveyance of all the semantics of CONS as inherent mandatory capabilities of the packet layer protocol. The non-suppen of these mandatory capabilities in actual implementations will result in inefficiencies since an additional convergence protocol will become necessary to make up for the non-support. Where it is intended that network equipment (such as the packet switches shown in diagrams b) and c) of Figure 4X.610 participate in the support of CONS, this equipment a) must co
