1、 INTERNATIONAL TELECOMMUNICATION UNION ITU-T X.111TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (02/2003) SERIES X: DATA NETWORKS AND OPEN SYSTEM COMMUNICATIONS Public data networks Network aspects Principles for the routing of international frame relay traffic ITU-T Recommendation X.111 ITU-T X-S
2、ERIES 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 INTERCONNEC
3、TION 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 Conf
4、ormance 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 se
5、rvice 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 f
6、unctions 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 Recommendations. IT
7、U-T Rec. X.111 (02/2003) i ITU-T Recommendation X.111 Principles for the routing of international frame relay traffic Summary The purpose of this Recommendation is to provide network operators with the information necessary to ensure that Frame Relay data traffic can be routed effectively and effici
8、ently across the International Public Data Network. Guidelines and general principles for the planning of Public Frame Relay Data networks and the routing of International Frame Relay Traffic are provided. In particular guidance on the incorporation of service requirements into the network routing p
9、rocess is provided. Principles for routing in the case of Frame Relay/ATM interworking are also provided. Source ITU-T Recommendation X.111 was prepared by ITU-T Study Group 17 (2001-2004) and approved under the WTSA Resolution 1 procedure on 13 February 2003. Keywords Frame Relay, Public Frame Rela
10、y Data Network, Routing. ii ITU-T Rec. X.111 (02/2003) 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
11、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, establishes the topics for study by the ITU-T study
12、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 standards are prepared on a collaborative basis wi
13、th 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 possibility that the practice or implementation of this
14、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 Recommendation development process. As of the date o
15、f 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 information and are therefore strongly urged to consult th
16、e TSB patent database. ITU 2003 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.111 (02/2003) iii CONTENTS Page 1 Introduction 1 2 Scope 1 3 References. 1 4 Definitions 2 5 Abbreviations 3 6 Refere
17、nce configurations 3 6.1 Scenario 1: Routing between PFRDNs 3 6.2 Scenario 2: Interworking with ATM networks 4 7 Basic principles in routing frame relay traffic 4 8 Implications of service defined network connections for FR routing 5 9 Overview of the routing process. 5 9.1 General . 5 9.2 DTE-DCE i
18、nterface 6 9.3 Originating local switch . 6 9.4 Transit networks and switches (national and international). 7 10 Structure/topology of the international frame relay network . 7 10.1 National network parts . 7 10.2 International Network parts 8 11 Network numbering and identification and the relation
19、 to routing 8 11.1 Networks numbered under X.121. 9 11.2 Networks numbered under E.164. 9 11.3 Number plan interworking . 9 11.4 Identification of transit networks 9 Annex A International Routing plan for PFRDNs Examples of typical FR routes . 10 A.1 Introduction 10 A.2 Examples of typical routes .
20、10 A.2.1 Direct route (high usage route). 10 A.2.2 Routes via intermediate transit networks . 11 A.2.3 Use of Alternative routes 11 A.2.4 Routing plan in cases where direct routes are provisioned 11 A.2.5 Routing plan in cases where direct routes are not provisioned 12 A.3 Rerouting due to call set-
21、up failure 13 iv ITU-T Rec. X.111 (02/2003) Page Annex B Frame relay routing in the case of interworking with ATM networks 14 B.1 Introduction 14 B.2 Bilateral agreements/interworking units. 14 B.3 Number-plan Interworking. 14 B.4 Use of transit networks/location of interworking units 14 B.5 Signall
22、ing procedures . 14 B.6 Interworking scenarios . 14 B.6.1 Network interworking 15 B.6.2 Network Interworking between two PFRDNs using an ATM Network as a transit . 15 B.6.3 Service interworking 16 Annex C Analysis of information required for routing. 16 C.1 Calling party number 16 C.2 Incoming route
23、 DLCI . 16 C.3 Called party number . 16 C.4 Bearer capability: Link Layer core parameters 16 C.5 Priority and service class parameters . 17 C.6 Maximum end-to-end transit delay 17 C.7 Transit network selection . 17 C.8 Network management conditions. 18 C.9 Time, event and state conditions 18 ITU-T R
24、ec. X.111 (02/2003) 1 ITU-T Recommendation X.111 Principles for the routing of international frame relay traffic 1 Introduction 1.1 This Recommendation provides general principles and guidelines for the routing of international frame relay data traffic. The Frame Relay Data Transmission Service as d
25、efined by ITU-T Recs X.36 and X.76 provides a wide range of services such as closed user group, reverse charging, transit network selection, transfer and discard priorities and selection of service classes. Each service must be supported by a minimum level of network capability. For each connection
26、requested by a user, the network must provide the appropriate switching, signalling and transmission capabilities required to successfully route the call to the required destination. 1.2 The purpose of this Recommendation is to provide network operators with the information necessary to ensure that
27、Frame Relay data traffic can be routed effectively and efficiently across the International Public Data Network. In particular guidance on the incorporation of service requirements into the network routing process is provided. 1.3 This Recommendation establishes basic principles on which to base net
28、work design and routing decisions. It provides detailed information on the mapping between Frame Relay Data Transmission services, and the network capabilities (e.g., transmission links, signalling systems, etc.) required to support and route a call. Guidance on the conveyance and use of routing inf
29、ormation within network components is also included. NOTE Within this Recommendation the term Public Frame Relay Data Network can be used interchangeably with the term Public Data Network providing the Frame Relay Data Transmission Service. The term ATM Network can be used interchangeably with the t
30、erm B-ISDN. 2 Scope 2.1 The scope of this Recommendation is the routing of international frame relay data traffic supported by the service capabilities defined in ITU-T Rec. X.76, “Network-to-network interface between public networks providing PVC and/or SVC frame relay data transmission service“, i
31、.e., routing principles for PVC or SVC frame relay connections. The scope of this Recommendation is limited to Public Data Networks providing the Frame Relay Data Transmission Service. Contents of this Recommendation will be reviewed/extended in order to satisfy operational needs which will arise ac
32、cording to the evolution of public frame relay data networks. 2.2 This Recommendation is intended to provide a single definitive reference for Frame Relay routing. It is a companion document to ITU-T Rec. X.110, “International routing principles and routing plan for the Public Data Network“. 2.3 Arr
33、angements for the routing of international frame relay data traffic between PFRDNs and the Frame Mode Bearer Service provided by N-ISDNs is outside the scope of this Recommendation. 3 References The following ITU-T Recommendations and other references contain provisions which, through reference in t
34、his text, constitute provisions of this Recommendation. At the time of publication, 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 ed
35、ition of the Recommendations and other references listed below. A list of the 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. 2 ITU-T Rec. X.111 (02/2003)
36、 This Recommendation is related to and is compatible with the following Recommendations: ITU-T Recommendation E.164 (1997), The international public telecommunication numbering plan. ITU-T Recommendation E.177 (1996), B-ISDN routing. ITU-T Recommendation I.555 (1997), Frame Relaying Bearer Service i
37、nterworking. ITU-T Recommendation X.36 (2000), 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.46 (1998), Access to FRDTS via B-ISDN. ITU
38、-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.78 (1999), Interworking procedures between networks providing frame relay data transmission services via B-ISDN. ITU-T Recommenda
39、tion X.110 (2002), International routing principles and routing plan for public data networks. ITU-T Recommendation X.121 (2000), International numbering plan for public data networks. ITU-T Recommendation X.124 (1999), Arrangements for the interworking of the E.164 and X.121 numbering plans for fra
40、me relay and ATM networks. ITU-T Recommendation X.125 (1998), Procedure for the notification of the assignment of international network identification codes for public frame relay data networks and ATM networks numbered under the E.164 numbering plan. ITU-T Recommendation X.144 (2000), User informat
41、ion transfer performance parameters for data networks providing international frame relay PVC service. ITU-T Recommendation X.145 (1996), Performance for data networks providing international frame relay SVC service. ITU-T Recommendation X.146 (2000), Performance objectives and quality of service cl
42、asses applicable to frame relay. ITU-T Recommendation X.300 (1996), General principles for interworking between public networks and between public networks and other networks for the provision of data transmission services. ITU-T Recommendation X.301 (1996), Description of the general arrangements f
43、or call control within a subnetwork and between subnetworks for the provision of data transmission services. ITU-T Recommendation X.329 (2000), General arrangements for interworking between networks providing frame relay data transmission services and B-ISDN. 4 Definitions This terms and their defin
44、itions used in this Recommendation are consistent with those defined in ITU-T Recs E.164, E.177, I.155, X.36, X.46, X.76, X.78, X.110, X.121, X.124 and X.125. ITU-T Rec. X.111 (02/2003) 3 5 Abbreviations This Recommendation uses the following abbreviations: ATM Asynchronous Transfer Mode B-ISDN Broa
45、dband Integrated Services Digital Network DCE Data Circuit-terminating Equipment DLCI Data Link Connection Identifier DNIC Data Network Identification Code DTE Data Terminal Equipment FR Frame Relay FRDTS Frame Relay Data Transmission Service IDSE International Data Switching Exchange ISDN Integrate
46、d Services Digital Network IWF Interworking Function ND Number Digits NPI Numbering Plan Identification NSAP Network Service Access Point (address) PDN Public Data Network PFRDN Public Frame Relay Data Network PVC Permanent Virtual Circuit STE Signalling Terminal Equipment SVC Switched Virtual Circu
47、it TON Type of Number VC Virtual circuit 6 Reference configurations 6.1 Scenario 1: Routing between PFRDNs Figure 1 provides a reference model for the most common environment in which the routing principles defined in this Recommendation apply. That is the routing of international frame relay data t
48、raffic between public data networks proving the FRDTS. Public Frame Relay Data Networks will be interconnected utilizing the network-to-network interface defined in ITU-T Rec. X.76. 4 ITU-T Rec. X.111 (02/2003) X.111_F01Public datanetwork Aproviding FRDTSSTE STESTESTEX.76 X.76X.76DTEDCEDCEPublic dat
49、anetwork Bproviding FRDTSPublic datanetwork Cproviding FRDTSDTESTESTEFigure 1/X.111 General environment in which X.111 applies 6.2 Scenario 2: Interworking with ATM networks Figure 2 is a representation of the possible interworking scenarios which may require frame relay traffic to be routed between networks. Interconnection of PFRDN and ATM networks may require an interworking function. Refer to ITU-T Rec. X.46 for detailed procedures for access to FRDTS via B-ISDN. Refer to ITU-T Rec. X.78 for detailed proce
