1、 INTERNATIONAL TELECOMMUNICATION UNION ITU-T X.110TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (04/2002) SERIES X: DATA NETWORKS AND OPEN SYSTEM COMMUNICATIONS Public data networks Network aspects International routing principles and routing plan for Public Data Networks ITU-T Recommendation X.11
2、0 ITU-T X-SERIES 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
3、INTERCONNECTION 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.28
4、0X.289 Conformance 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 Qu
5、ality of service 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 M
6、anagement functions 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 For further details, please refer to the list of ITU-T Recommen
7、dations. ITU-T Rec. X.110 (04/2002) i ITU-T Recommendation X.110 International routing principles and routing plan for Public Data Networks Summary This Recommendation provides high level general principles and guidelines that should be applied by Network Operators for the routing of international d
8、ata traffic across interconnected public data networks. The aim of this Recommendation is to provide network operators with the necessary information to ensure that data traffic can be effectively and economically routed across interconnected public data networks making best use of the available net
9、work resources. Although this Recommendation is focused towards packet switched data networks (such as X.25 and Frame Relay), the principles are applicable to both circuit-switched and packet-switched public data networks. Source ITU-T Recommendation X.110 was revised by ITU-T Study Group 17 (2001-2
10、004) and approved under the WTSA Resolution 1 procedure on 13 April 2002. ii ITU-T Rec. X.110 (04/2002) 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
11、permanent organ of ITU. ITU-T is responsible for studying technical, operating 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, est
12、ablishes the topics for study by the ITU-T study groups which, in turn, produce 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 s
13、tandards are prepared on a collaborative basis with ISO and IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibi
14、lity 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, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Rec
15、ommendation 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 required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest informati
16、on and are therefore strongly urged to consult the TSB patent database. ITU 2002 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. ITU-T Rec. X.110 (04/2002) iii CONTENTS Page 1 Introduction 1 2 Scope 1 3 Referen
17、ces. 3 4 Definitions 4 5 Abbreviations 4 6 Description of an international route 5 7 General routing principles 5 8 Specific routing possibilities through the International PDN. 6 8.1 Routing possibilities required for maintaining the quality of service 6 8.2 Service characteristics associated with
18、a route. 6 8.3 Specific conditions associated with a route 6 9 Routing procedures applicable to international interworking between PDNs of the same type, between PSPDNs and ISDNs/PSTN and also between PFRDNs and ATM networks 7 9.1 Use of DNICs . 7 9.2 Number plan interworking . 7 9.2.1 Use of escape
19、 codes to facilitate number plan interworking 7 9.2.2 Significance of escape codes for routing 8 9.3 Number plan interworking for frame relay and ATM Networks . 8 10 Identification of IDSEs and ISDNs involved in an international call 8 11 Multiple IDSEs provided within one Country or Administration
20、9 11.1 In the originating or destination country 9 11.2 In a transit country 9 12 International routing plan . 9 13 Network information required to enable optimum routings to be planned 10 Annex A Terms and definitions related to routing in the PDN 10 Annex B The use of satellite links in overall PD
21、N routes 11 B.1 General considerations . 11 B.2 Principles in each PDN. 12 B.2.1 Originating national PDN. 12 B.2.2 Originating/transit IDSEs . 12 B.2.3 Destination IDSE 12 iv ITU-T Rec. X.110 (04/2002) Page B.2.4 Destination national PDN. 12 Annex C Routing information 12 Annex D International rout
22、ing plan Examples of routes . 13 D.1 Introduction 13 D.2 Examples of typical routes . 13 D.2.1 Direct route (high usage route). 13 D.2.2 Routes via intermediate countries (low volumes of traffic) . 13 D.2.3 Alternative route. 14 D.2.4 Routing plan in cases where direct routes are provisioned 14 D.2.
23、5 Routing plan in cases where direct routes are not provisioned 15 D.3 Rerouting 16 ITU-T Rec. X.110 (04/2002) 1 ITU-T Recommendation X.110 International routing principles and routing plan for Public Data Networks 1 Introduction This Recommendation specifies the high level routing principles and gu
24、idelines that should be applied for the establishment of calls across interconnecting public data networks. Although this Recommendation is focused towards packet switched data networks (such as X.25 and Frame Relay), the principles are applicable to both circuit-switched and packet-switched public
25、data networks. 2 Scope 2.1 The scope of this Recommendation is the provision of general principles and guidelines that should be applied by Network Operators for the routing of international data traffic across interconnected public data networks. The aim of this Recommendation is to provide network
26、 operators with the necessary information to ensure that data traffic can be effectively and economically routed across interconnected public data networks utilizing the available network resources. It is recognized that the guidelines will need to be reviewed periodically to ensure that it is in st
27、ep with actual practice taking place within the international public data networks. A model of the international public data network is illustrated in Figure 1. This model consists of a set of national public networks and shows the interconnection of national public data networks and International D
28、ata Switching Exchanges (IDSEs) and reflects the manner in which public data networks have evolved in different ways in many countries. The model shown illustrates six types of networks that have evolved as follows: a) Some countries may have more than one PDN and also more than one IDSE. See countr
29、y A in Figure 1. b) Some countries may have one IDSE which stands alone from that countrys PDN. See country B in Figure 1. c) Some countries may have one PDN and gain international access through one IDSE. See country C in Figure 1. d) Some countries may not have a PDN but utilize an IDSE for intern
30、ational connections. See country D in Figure 1. e) Some countries may have more than one PDN each with its own IDSE. See country E in Figure 1. f) Some countries may have more than one PDN each sharing one or more IDSE. See country F in Figure 1. 2.2 Circuits between IDSEs in the same country are no
31、t classed as international links. 2.3 A list of the terms and definitions used in this Recommendation are recorded in Annex A. 2 ITU-T Rec. X.110 (04/2002) OPQWVRSUTT0724690-02Plan 2 International Public Data Network (IPDN) National PDNCountry B Country C Country DCountry A Country E Country FPlan 1
32、 National PDNsRefer to 2.1, items b) and d)Indicates a country or a geographical areaPossible data links which may be classified as part of an international data connectionNational PDNNational PDNNational PDNNational PDNNational PDNNational PDNNational PDNNational PDNFigure 1/X.110 International pub
33、lic data network model ITU-T Rec. X.110 (04/2002) 3 3 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 publication, the editions indicated were valid. All Recomme
34、ndations 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 currently valid ITU-T Recommendations is regularly p
35、ublished. ITU-T Recommendation X.1 (2000), International user classes of service in, and categories of access to, public data networks and Integrated Services Digital Networks (ISDNs). ITU-T Recommendation X.7 (2000), Technical characteristics of data transmission services. ITU-T Recommendation X.60
36、 (1988), Common channel signalling for circuit-switched data applications. ITU-T Recommendation X.61 (1988), Signalling System No. 7 Data user part. ITU-T Recommendation X.70 (1988), Terminal and transit control signalling system for start-stop services on international circuits between anisochronou
37、s data networks. ITU-T Recommendation X.71 (1988), Decentralized terminal and transit control signalling system on international circuits between synchronous data networks. ITU-T Recommendation X.75 (1996), Packet-switched signalling system between public networks providing data transmission service
38、s. ITU-T Recommendation X.75 Corrigendum 1 (1998). ITU-T Recommendation X.76 (2000), Network-to-network interface between public networks providing PVC and/or SVC frame relay data transmission service. ITU-T Recommendation X.92 (1988), Hypothetical reference connections for public synchronous data n
39、etworks. ITU-T Recommendation X.115 (1995), Definition of address translation capability in public data networks. ITU-T Recommendation X.116 (1996), Address translation registration and resolution protocol. ITU-T Recommendation X.121 (2000), International numbering plan for public data networks. ITU
40、-T Recommendation E.166/X.122 (1998), Numbering plan interworking for the E.164 and X.121 numbering plans. ITU-T Recommendation X.123 (1996), Mapping between escape codes and TOA/NPI for E.164/X.121 numbering plan interworking during the transition period. ITU-T Recommendation X.124 (1999), Arrangem
41、ents for the interworking of the E.164 and X.121 numbering plans for frame relay and ATM Networks. ITU-T Recommendation X.125 (1998), Procedures for the notification of the assignment of international network identification codes for public frame relay data networks and ATM networks numbered under t
42、he E.164 numbering plan. ITU-T Recommendation X.130 (1988), Call processing delays in public data networks when providing international synchnronous circuit-switched data services. 4 ITU-T Rec. X.110 (04/2002) ITU-T Recommendation X.131 (1988), Call blocking in public data networks when providing in
43、ternational synchronous circuit-switched data services. ITU-T Recommendation X.135 (1997), Speed of service (delay and throughput) performance values for public data networks when providing international packet-switched services. ITU-T Recommendation X.136 (1997), Accuracy and dependability performa
44、nce values for public data networks when providing international packet-switched services. ITU-T Recommendation X.144 (2000), User information transfer performance parameters for data networks providing international frame relay PVC service. ITU-T Recommendation X.145 (1996), Performance for data ne
45、tworks providing international frame relay SVC service. ITU-T Recommendation X.146 (2000), Performance objectives and quality of service classes applicable to frame relay. ITU-T Recommendation X.353 (1988), Routing principles for interconnecting public maritime mobile satellite data transmission sys
46、tems with public data networks. 4 Definitions Within the public switched telephone and public data network environment, the terms used for all networks and services must be compatible and consistent. Therefore this Recommendation, in addition to the terms defined herein, relies on a list of terms an
47、d definitions contained in ITU-T Recs. E.164, X.121, X.122, X.25, X.75, X.36 and X.76. A list of terms and definitions is given in Annex A. 5 Abbreviations This Recommendation uses the following abbreviations. ATM Asynchronous Transfer Mode CC Country Code DCC Data Country Code DCE Data Circuit-term
48、inating Equipment DNIC Data Network Identification Code DTE Data Terminal Equipment FR Frame Relay IDSE International Data Switching Exchange ISDN Integrated Services Digital Network ITU-T International Telecommunication Union Telecommunication Standardization Sector NN National Number NPI Numbering
49、 Plan Identifier NTN Network Terminal Number PDN Public Data Network PFRDN Public Frame Relay Data Network PNIC Private data Network Identification Code ITU-T Rec. X.110 (04/2002) 5 PSPDN Packet Switched Public Data Network PSTN Public Switched Telephone Network ROA Recognized Operating Agency ToA Type of Address ToN Type of Number 6 Description of an international route 6.1 The basic function of routing a call (or selecting a route for a call) consists of selecting, at each switching
