1、_ STD.ITU-T RECMN X-23Li-ENGL 1994 m Lib257L Ob2038b b77 INTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU DATA NETWORKS AND OPEN SYSTEM COMMUNICATIONS OPEN SYSTEMS INTERCONNECTION - CONNECTIONLESS-MODE PROTOCOL SPEC I FI CATI0 NS X.234 (07/94) INFORMATION T
2、ECHNOLOGY - CONNECTIONLESS-MODE TRANSPORT PROTOCOL FOR PROVIDING THE OS1 SERVICE ITU-T Recommendation X.234 (Previously “CCITT Recommendation”) Foreword ITU (International Telecommunication Union) is the United Nations Specialized Agency in the field of telecommunications. The ITU Telecommunication
3、Standardization Sector (ITU-T) is a permanent organ of the ITU. Som? 179 member countries, 84 telecom operating entities, 145 scientific and industrial organizations and 38 international organizations participate in ITU-T which is the body which sets world telecommunications standards (Recommendatio
4、ns). The approval of Recommendations by the Members of ITU-T is covered by the procedure laid down in WTSC Resolution No. 1 (Helsinki. 1993). In addition, the World Telecommunication Standardization Conference (WTSC). which meets every four years, approves Recommendations submitted to it and establi
5、shes the study programme for the following period. In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with IS0 and IEC. The text of ITU-T Recommendation X.234 was approved on Ist July 1994. The identical text is als
6、o published as ISO/IEC International Standard 8602. NOTE In this Recommendation, the expression “Administration” is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. O ITU 1994 All rights reserved. No part of this publication may be reproduce
7、d or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. STD-ITU-T RECMN X-234-ENGL 1774 m 48b257L Ob20388 94T m ITU-T X-SERIES RECOMMENDATIONS DATA NETWORKS AND OPEN SYSTEM COMMUNICATIONS (FEBRUARY 1994) O
8、RGANIZATION OF X-SERIES RECOMMENDATIONS Subject Area PUBLIC DATA NETWORKS Services and Facilities Interfaces Transmission, Signalling and Switching Network Aspects Maintenance Administrative Arrangements I OPEN SYSTEMS INTERCONNECTION Model and Notation Service Definitions Connection-mode Protocol S
9、pecifications Connectionless-mode Protocol Specifications PICS Proformas Protocol Identification Security Protocols Layer Managed Objects Conformance Testing INTERWORKING BETWEEN NETWORKS General Mobile Data Transmission Systems Management MESSAGE HANDLING SYSTEMS DIRECTORY OS1 NETWORKING AND SYSTEM
10、 ASPECTS Networking Naming, Addressing and Registration Abstract Syntax Notation One (ASN. 1) OS1 MANAGEMENT SECURITY OS1 APPLICATIONS Commitment, Concurrency and Recovery Transaction Processing Remote Operations OPEN DISTRIBUTED PROCESSING Recommendation Series X.1-X. 19 x.20-x.49 X.50-X.89 X.90-X.
11、 149 X. 150-X. 179 X.180-X.199 x.200-x.209 X.210-X.219 X.220-X.229 X.230-X.239 X.240-X.259 X.260-X.269 X.270-X.279 X.280-X.289 X .290-X. 299 x.300-x.349 X.350-X.369 X.370-X.399 x.400-x.499 x.500-x.599 x.600-x.649 X.650-X.679 X.680-X.699 x.700-x.799 X.800-X.849 X.850-X.859 X.860-X.879 X.880-X.899 x.9
12、00-x.999 STD-ITU-T RECMN X-234-ENGL 1774 48b257L Ob20387 38b D CONTENTS Introduction . 1 1 scope . 2 Normative references . Identical Recommendations I International Standards . : Paired Recommendations I International Standards equivalent in technical content i . 2 . i 2.2 SECTION 1 - GENERAL . i .
13、 3 Definitions 3.1 Reference Model definitions . 3.2 This Recommendation I International Standard uses the following terms defined in CCITT Rec . X.290 I ISOAEC 9646-1 : 3.3 Additional definitions . 4 Abbreviations . 4.1 Data units 4.2 Types of transport-protocol-data-units 4.3 TPDU fields 4.4 Param
14、eters . 4.5 Miscellaneous . Overview of the transport protocol 5.1 Service provided by the Transport Layer 5.2 Service assumed from the Network Layer 5.3 Functions of the Transport Layer 5.4 Model of the Transport Layer . SECTION 2 - CONNECTIONLESS-MODE TRANSPORTPROTOCOL SPECIFICATION . 6 Protocol m
15、echanisms . 6 . i Transport-protocol-data-unit (TPDU) transfer 6.2 Transfer over the connectionless-mode network service 6.3 Transfer over the connection oriented network service 6.4 Checksum Encoding of the unit data (UD) TPDU . 7.1 General 7.2 Unit data (UD) TPDU . 8 Conformance Annex A - State ta
16、ble Annex B - PICS proforma B.l Introduction . B.2 B.3 Instructions for Completing the PICS Proforma . B.4 Identification . B.5 Base StandardRecornmendation Conformance B.6 General Statement of Conformance B.7 PICS Proforma Annex C - Checksum algorithms C.l Symbols C.2 Arithmetic conventions . C.3 C
17、.4 Algorithm for checking checksum parameters . 5 7 Abbreviations and special symbols . Algorithm for generating checksum parameters . ITU-T RW . X.234 (1994 E) Page iii 1 1 1 2 2 2 2 2 2 3 3 3 3 3 3 4 4 4 4 6 6 6 6 7 8 9 9 10 11 11 12 13 13 14 14 14 15 15 15 17 17 17 17 18 i Summary This Recommenda
18、tion I International Standard specifies: a) b) c) the procedures for the connectionless-mode transmission of data and protocol control information from one transport entity to one peer transport entity; the encoding of the transport protocol data units; and the functional requirements for implementa
19、tions claiming conformance to this Recommendation. ii ITU-T Rc X.234 (1994 E) STD-ITU-T RECMN X.234-ENGL L79L1 48b2571 Ob20371 T3L1 Introduction This Recommendation I International Standard is one of a set of Recommendations and Intemational Standards produced to facilitate the interconnection of co
20、mputer systems. The set of Recommendations and International Standards covers the services and protocols required to achieve such interconnection. This Recommendation I International Standard is positioned with respect to other related Recommendations and International Standards by the layers define
21、d in the Reference Model for Open Systems Interconnection (see ITU-T Rec. X.200 I ISODEC 7498-1). In particular. it is a protocol of the Transport Layer. It is most closely related to the transport service definition (see ITU-T Rec. X.214 I ISOIIEC 8072) and the network service definition (see CCITT
22、 Rec. X.2 I3 I ISOAEC 8348). The interrelationship between these Recommendations and International Standards is illustrated in Figure 1. The structure of this Recommendation I International Standard is similar to the structure of ITU-T Rec. X.224 I ISODEC 8073 in order to facilitate cross reference
23、between the two transport protocols. Connectionless-made transport service definition Connectioniess- transport protocd specification connectionless-mode network service definition TlS03030-Wa)f Figure 1 - Relationship between the connectionless-mode transport protocol and adjacent services ITU-T RH
24、. X.234 (1994 E) iii STD-ITU-T RECMN X-234-ENGL 1774 48b2571 Ob20372 970 ISOIEC 8602 : 1995 (E) INTERNATIONAL STANDARD ITU-T RECOMMENDATION INFORMATION TECHNOLOGY - PROTOCOL FOR PROVIDING THE OS1 CONNECTIONLESS-MODE TRANSPORT SERVICE 1 Scope This Recommendation I International Standard specifies a)
25、procedures for the connectionless-mode transmission of data and protocol control information from one transport entity to one peer transport entity; the encoding of the transport-protocol-data-units used for the transmission of data and control information; procedures for the correct interpretation
26、of transport protocol control information; and the functional requirements for implementations claiming conformance to this Recommendation I International Standard. b) c) d) The procedures are defined in terms of a) b) the interactions among peer transport entities through the exchange of transport-
27、protocol-data-units; the interactions between a transport entity and a transport service user through the exchange of transport service primitives; and the interaction between a transport entity and a network service provider through the exchange of network service primitives. c) This Recommendation
28、 I International Standard specifies the connectionless-mode transport protocol and provides the PICS Proforma in compliance with the relevant requirements, and in accordance with the relevant guideline, given in CCIT Rec. X.291 I ISOAEC 9646-2. The protocol for providing the connection-mode transpor
29、t service is specified in IT-T Rec. X.224 I ISOAEC 8073. 2 Normative references The following Recommendations and International Standards contain provisions, which through references in the text, constitute provisions of this Recommendation I International Standard. At the time of publication, the e
30、ditions indicated were valid. All Recommendations and Standards are subject to revision, and parties to agreements based on this Recommendation I International Standard are encouraged to investigate the possibility of applying the most recent edition of the Recommendations and Standards listed below
31、. Members of IEC and IS0 maintain registers of currently valid International Standards. The Telecommunication Standardization Bureau of the maintains a list of currently valid ITU-T Recommendations. 2.1 Identical Recommendations I International Standards - ITU-T Recommendation X.200 (1994) I ISOAEC
32、7498-1: 1994, Information technology - Open Systems Interconnection - Basic Reference Model. CCITT Recommendation X.213 (1992) I ISOAEC 8348:1993, Information technology - Network service definition for Open Systems Interconnection ITU-T Recommendation X.214 (1993) I ISOAEC 8072:1994, Information te
33、chnology - Open System Interconnection - Transport service definition. - - ITU-T Rec. X.234 (1994 E) 1 STD-ITU-T RECMN X-23Li-ENGL L77Li 48b2571 Ob20373 807 M ISO/iEC 8602 : 1995 (E) Paired Recommendations I International Standards equivalent in technical content - ITU-T Recommendation X.224 (1993),
34、 Protocol for providing the OS1 connection-mode transport service. ISO/IEC 8073: 1992, Information technology - Telecommunications and information exchange between systems - Open Systems Interconnection - Protocol .for providing the connecton-mode transport service. -T Recommendation X.264 (1993). T
35、ransport protocol identification mechanism. ISO/IEC 1 1570: 1992, Information technology - Telecommunications and information exchange between system - Open Systems Interconnection - Transport protocol identification mechanism. CCIIT Recommendation X.290 (1992), OS1 conformance testing methodology a
36、nd framework for protocol Recommendations for CCllT applications - General Concepts. ISO/IEC 9646- 1 : 199 1, Information technology - Open Systems Interconnection - Conformance testing methodologies and framework - Pan I: General concepts. CCW Recommendation X.291 (1992). OS1 conformance testing me
37、thodology and framework for protocol Recommendations for CCITT applications -Abstract test suite specpcation. ISOLEC 9646-2: 1991, Information technology - Open Systems Interconnection - Conformance testing methodologies and framework - Pan 2: Abstract test suite speccation. - - - SECTION 1 - GENERA
38、L 3 Definitions For the purposes of this Recommendation I International Standard, the following definitions apply. 3.1 Reference Model definitions This Recommendation I International Standard is based on the concepts developed in ITU-T Rec. X.200 I ISOAEC 7498-1, and makes use of the following terms
39、 defined therein: Transport layer; transport service; transport-service-access-point; transport-service-access-point-address ; transport-service-data-uni t; network Layer; network service; network connection; network-service access-point; transport protocol; connectionless-mode transmission. 3.2 Thi
40、s Recommendation I International Standard uses the following terms defined in CCIT Rec. X.290 I a) PICS Proforma; b) ISO/IEC 9646-1 protocol implementation conformance statement (PICS). 3.3 Additional definitions For the purposes of this Recommendation I International standard, the following definit
41、ions apply. 2 ITU-T RW. X.234 (1994 E) STD-ITU-T RECMN X.234-ENGL 1794 m q8b257L Ob20374 743 m ISO/IEC 8602 : 1995 (E) 3.3.1 Source-transport-address Identifies the TSAP through which the transport service user may act as the source of data during a particular instance of transport connectionless-mo
42、de transmission. 3.3.2 Destination-transport-address Identifies the TSAP through which the transport service user may act as the sink of data during a particular instance of transport connectionless-mode transmission. 33.3 Connection oriented transport protocol See 3.1, “transport protocol”. 3.3.4 S
43、ee 3. 33.5 See 3. 33.6 Connection oriented transport service , ”transport service”. Connection oriented network service . “network service”. Connectionless-mode transport protocol Transport protocol for providing the connectionless-mode transport service. 3.3.7 Connectionless-mode transport service
44、Transport service providing connectionless-mode transmission. 3.3.8 Connectionless-mode network service Network service providing connectionless-mode transmission. 4 Abbreviations 4.1 Data units TPDU Transport-protocol-data-uni t TSDU Transport-service-data-uni t NSDU Network-servicedata-uni t 4.2 T
45、ypes of transport-protocol-data-units UD TPDU Unit data TPDU UN TPDU Use of network connection TPDU (defined in ITU-T Rec. 264 I ISOAEC 11570) 4.3 TPDU fields LI Length indicator 4.4 Parameters Source TSAP-ID Destination TSAP-ID Checksum 4.5 Miscellaneous TS-user Transport service user TSAP Transpor
46、t-service-access-point NSAP Network-service-access-point ITU-T Rw. X.234 (1994 E) 3 5 Overview of the transport protocol Frimitives T-UNITDATA wuest T-UNITDATA indication 5.1 Service provided by the Transport Layer PanillIeters Source address Destination address Quaiity of service TS-userdata source
47、 address Destination address Quaiity of service TS-userdata The service provided by the protocol described herein is a connectionless-mode transport service. The connectionless- mode transport service is described in -T Rec. X.214 I ISO/IEC 8072. The transport service primitives provided are summari
48、zed in Table 1. Table 1 - Transport service primitives 5.2 Service assumed from the Network Layer The transport protocol described in this Recommendation I International Standard can operate over the connection oriented network service and over the connectionless-mode network service as defined in C
49、CK Rec. X.213 I ISO/IEC 8348. When operating over the connection oriented network service. the network service primitives given in Table 2 are used. When operating over the connectionless-mode network service, the network service primitives given in Table 3 are used. 5.3 Functions of the Transport Layer 53.1 Connectionless-mode transfer functions The purpose of connectionless-mode transfer is to allow the transfer of data between correspondent TS-users on a connectionless basis. This service provides for single-access data transfer for correspondent TS-users without
