1、 INTERNATIONAL TELECOMMUNICATION UNION ITU-T X.7TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (04/2004) SERIES X: DATA NETWORKS AND OPEN SYSTEM COMMUNICATIONS Public data networks Services and facilities Technical characteristics of data transmission services ITU-T Recommendation X.7 ITU-T X-SERIE
2、S RECOMMENDATIONS DATA NETWORKS AND OPEN SYSTEM COMMUNICATIONS PUBLIC DATA NETWORKS Services and facilities X.1X.19 Interfaces X.20X.49 Transmission, signalling and switching X.50X.89 Network aspects X.90X.149 Maintenance X.150X.179 Administrative arrangements X.180X.199 OPEN SYSTEMS INTERCONNECTION
3、 Model and notation X.200X.209 Service definitions X.210X.219 Connection-mode protocol specifications X.220X.229 Connectionless-mode protocol specifications X.230X.239 PICS proformas X.240X.259 Protocol Identification X.260X.269 Security Protocols X.270X.279 Layer Managed Objects X.280X.289 Conforma
4、nce testing X.290X.299 INTERWORKING BETWEEN NETWORKS General X.300X.349 Satellite data transmission systems X.350X.369 IP-based networks X.370X.399 MESSAGE HANDLING SYSTEMS X.400X.499 DIRECTORY X.500X.599 OSI NETWORKING AND SYSTEM ASPECTS Networking X.600X.629 Efficiency X.630X.639 Quality of servic
5、e X.640X.649 Naming, Addressing and Registration X.650X.679 Abstract Syntax Notation One (ASN.1) X.680X.699 OSI MANAGEMENT Systems Management framework and architecture X.700X.709 Management Communication Service and Protocol X.710X.719 Structure of Management Information X.720X.729 Management funct
6、ions and ODMA functions X.730X.799 SECURITY X.800X.849 OSI APPLICATIONS Commitment, Concurrency and Recovery X.850X.859 Transaction processing X.860X.879 Remote operations X.880X.899 OPEN DISTRIBUTED PROCESSING X.900X.999 TELECOMMUNICATION SECURITY X.1000 For further details, please refer to the lis
7、t of ITU-T Recommendations. ITU-T Rec. X.7 (04/2004) i ITU-T Recommendation X.7 Technical characteristics of data transmission services Summary This Recommendation describes the technical characteristics of data transmission services, including leased circuit, circuit switched, packet switched (incl
8、uding ISDN), and frame relay data transmission services. Technical characteristics include access attributes, interfaces and quality of service parameters. This Recommendation also contains definitions of particular optional user facilities and terminology, includes access to frame relay data transm
9、ission service via B-ISDN and some optional user facilities for frame relay. This revision includes interworking data transmission services with Internet. Source ITU-T Recommendation X.7 was approved on 29 April 2004 by ITU-T Study Group 17 (2001-2004) under the ITU-T Recommendation A.8 procedure. i
10、i ITU-T Rec. X.7 (04/2004) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operatin
11、g and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produ
12、ce Recommendations on these topics. The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In this
13、 Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure e.g., inte
14、roperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words “shall“ or some other obligatory language such as “must“ and the negative equivalents are used to express requirements. The use of such words does not suggest t
15、hat compliance with the Recommendation is required of any party. INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence,
16、 validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be
17、 required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. ITU 2004 All rights reserved. No part of this publication may be reproduced, by any means whatsoever
18、, without the prior written permission of ITU. ITU-T Rec. X.7 (04/2004) iii CONTENTS Page 1 Scope 1 2 References. 1 3 Terminology . 6 4 Abbreviations 8 5 Public data transmission services . 9 5.1 General aspects of data transmission services 11 5.2 Technical characteristics of circuit switched data
19、transmission services. 13 5.3 Technical characteristics of packet switched data transmission services provided by PSPDN or ISDN. 16 5.4 Technical characteristics of frame relay data transmission services provided by FRPDN. 23 5.5 Interworking between PDNs and the Internet 26 6 Optional user faciliti
20、es 27 6.1 Data transfer related facilities. 34 6.2 Facilities to convey user data other than during the data transfer phase 38 6.3 Addressing related facilities . 38 6.4 Routing related facilities. 40 6.5 Charging related facilities. 42 6.6 Protection related facilities. 44 6.7 Data link layer capab
21、ilities . 47 6.8 Multipoint related facilities 48 6.9 Other optional user capabilities/facilities . 48 ITU-T Rec. X.7 (04/2004) 1 ITU-T Recommendation X.7 Technical characteristics of data transmission services 1 Scope 1.1 The X-series ITU-T Recommendations define the wide range of capabilities avai
22、lable in Public Data Networks (PDNs). These capabilities reflect many aspects of using a PDN: available services; user interfaces, including the concepts of user class of service and categories of access; addressing and routing; performance parameters; status information; optional features that may
23、be available to complement the basic services; and interworking with other networks. 1.2 To use the wide range of capabilities of public data networks effectively and efficiently, users need to be well informed. Numerous ITU-T Recommendations have been developed that define and specify these capabil
24、ities. The intent of this Recommendation is to provide a concise, high-level overview of the capabilities available in public data networks and the associated ITU-T Recommendations in which they are discussed. It is suggested that readers of this Recommendation consult the referenced ITU-T Recommend
25、ations for further details. 1.3 The scope of this Recommendation is to provide a summary of the family of ITU-T X.1-X.199, X.300-X.399-series Recommendations that discuss technical characteristics of data transmission services in public data networks. Technical characteristics include access attribu
26、tes, interfaces, and quality of service parameters. The X-series ITU-T Recommendations within the scope of this Recommendation cover the following: services and optional user facilities; interfaces; transmission, signalling and switching; network aspects including numbering and routing; performance
27、and quality of service aspects; and interworking between networks, providing data transmission services. 1.4 In addition to defining the data transmission capabilities available in PDNs as listed above, the X-series ITU-T Recommendations specify many other aspects of data communications which are be
28、yond the scope of this Recommendation. These aspects are: X.200-series: Open Systems Interconnection (OSI), including protocol-testing methodology; X.400-series: Message Handling Systems; X.500-series: Directory; X.600-series: OSI Networking and System aspects; X.700-series: OSI Management; X.800-se
29、ries: OSI Distributed Applications including Security; and X.900-series: Open Distributed Processing. 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publicati
30、on, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the 2
31、ITU-T Rec. X.7 (04/2004) currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. ITU-T Recommendation E.164 (1997), The international public telecommunication num
32、bering plan. ITU-T Recommendation E.166/X.122 (1998), Numbering plan interworking for the E.164 and X.121 numbering plans. ITU-T Recommendation F.69 (1994), The international telex service Service and operational provisions of telex destination codes and telex network identification codes. ITU-T Rec
33、ommendation F.600 (2004), Service and operational principles for public data transmission service. ITU-T Recommendation I.112 (1993), Vocabulary of terms for ISDNs. ITU-T Recommendation I.233.1 (1991), Frame mode bearer services: ISDN frame relaying bearer service. ITU-T Recommendation I.240 (1988),
34、 Definition of teleservices. ITU-T Recommendation I.430 (1995), Basic user-network interface Layer 1 specification. ITU-T Recommendation I.431 (1993), Primary rate user-network interface Layer 1 specification. ITU-T Recommendation I.432 (1993), B-ISDN user-network interface Physical layer specificat
35、ion. ITU-T Recommendation Q.921 (1997), ISDN user-network interface Data link layer specification. ITU-T Recommendation Q.922 (1992), ISDN data link layer specification for frame mode bearer services. ITU-T Recommendation Q.931 (1998), ISDN user-network interface layer 3 specification for basic call
36、 control. ITU-T Recommendation Q.933 (2003), ISDN Digital Subscriber Signalling System No. 1 (DSS1) Signalling specifications for frame mode switched and permanent virtual connection control and status monitoring. ITU-T Recommendation X.1 (2000), International user classes of service in, and categor
37、ies of access to, public data networks and Integrated Services Digital Networks (ISDNs). ITU-T Recommendation X.2 (2000), International data transmission services and optional user facilities in public data networks and ISDNs. ITU-T Recommendation X.3 (2000), Packet Assembly/Disassembly facility (PA
38、D) in a public data network. ITU-T Recommendation X.5 (1996), Facsimile Packet Assembly/Disassembly facility (FPAD) in a public data network. ITU-T Recommendation X.6 (1997), Multicast service definition. ITU-T Recommendation X.8 (1994), Multi-aspect PAD (MAP) framework and service definition. ITU-T
39、 Rec. X.7 (04/2004) 3 ITU-T Recommendation X.20 (1988), Interface between Data Terminal Equipment (DTE) and Data Circuit-terminating Equipment (DCE) for start-stop transmission services on public data networks. ITU-T Recommendation X.20 bis (1988), Use on public data networks of Data Terminal Equipm
40、ent (DTE) which is designed for interfacing to asynchronous duplex V-series modems. ITU-T Recommendation X.21 (1992), Interface between Data Terminal Equipment and Data Circuit-terminating Equipment for synchronous operation on public data networks. ITU-T Recommendation X.21 bis (1988), Use on publi
41、c data networks of Data Terminal Equipment (DTE) which is designed for interfacing to synchronous V-series modems. ITU-T Recommendation X.22 (1988), Multiplex DTE/DCE interface for user classes 3-6. ITU-T Recommendation X.25 (1996), Interface between Data Terminal Equipment (DTE) and Data Circuit-te
42、rminating Equipment (DCE) for terminals operating in the packet mode and connected to public data networks by dedicated circuit. ITU-T Recommendation X.28 (1997), DTE/DCE interface for a start-stop mode data terminal equipment accessing the Packet Assembly/Disassembly facility (PAD) in a public data
43、 network situated in the same country. ITU-T Recommendation X.29 (1997), Procedures for the exchange of control information and user data between a Packet Assembly/Disassembly (PAD) facility and a packet mode DTE or another PAD. ITU-T Recommendation X.30 (1993), Support of X.21, X.21 bis and X.20 bi
44、s based Data Terminal Equipments (DTEs) by an Integrated Services Digital Network (ISDN). ITU-T Recommendation X.31 (1995), Support of packet mode terminal equipment by an ISDN. ITU-T Recommendation X.32 (1996), Interface between Data Terminal Equipment (DTE) and Data Circuit-terminating Equipment (
45、DCE) for terminals operating in the packet mode and accessing 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. ITU-T Recommendation X.33 (1996), Access to packet-switched data transm
46、ission services via frame relaying data transmission services. ITU-T Recommendation X.34 (1996), Access to packet-switched data transmission services via B-ISDN. ITU-T Recommendation X.35 (1993), Interface between a PSPDN and a private PSDN which is based on X.25 procedures and enhancements to defin
47、e a gateway function that is provided in the PSPDN. ITU-T Recommendation X.36 (2003), Interface between Data Terminal Equipment (DTE) and Data Circuit-terminating Equipment (DCE) for public data networks providing frame relay data transmission service by dedicated circuit. ITU-T Recommendation X.37
48、(1995), Encapsulation in X.25 packets of various protocols including frame relay. ITU-T Recommendation X.38 (1996), G3 facsimile equipment/DCE interface for G3 facsimile equipment accessing the Facsimile Packet Assembly/Disassembly facility (FPAD) in a public data network situated in the same countr
49、y. 4 ITU-T Rec. X.7 (04/2004) ITU-T Recommendation X.39 (1996), Procedures for the exchange of control information and user data between a Facsimile Packet Assembly/Disassembly (FPAD) facility and a packet mode Data Terminal Equipment (DTE) or another FPAD. ITU-T Recommendation X.45 (1996), Interface between Data Terminal Equipment (DTE) and Data Circuit-terminating Equipment (DCE) for terminals operating in the packet mode and connected to
