1、STD.ITU-T RECMN E.527-ENGL 1997 = qb257L b38800 b27 m INTERNATIONAL TELECOMMUNICATION UN I ON ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU E529 (05197) SERIES E: OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS Quality of service, network management and traf
2、fic engineering - Trafic engineering - Determination of the number of circuits in automatic and semi-automatic operation Network dimensioning using end-to-end GOS objectives ITU-T Recommendation E.529 (Previously CCITT Recommendation) STDeITU-T RECMN E-527-ENGL 1997 D Li8b2591 Ob38801 5b3 D ITU-T E-
3、SERIES RECOMMENDATIONS OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS IPERATION, NUMBERING, ROUTING AND MOBILE SERVICES INTERNATIONAL OPERATION OPERATIONAL PROVISIONS RELATING TO CHARGING AND ACCOUNTING IN THE INTERNATIONAL TELEPHONE SERVICE UTILIZATION OF THE INTE
4、RNATIONAL TELEPHONE NETWORK FOR NON- TELEPHONY APPLICATIONS ISDN PROVISIONS CONCEWG USERS ZUAWT OF SERVICE, NETWORK MANAGEMENT AND TRAFFIC ENGINEERING NETWORK MANAGEMENT International service statistics International network management Checking the quality of the international telephone service TRAF
5、FIC ENGINEERING Measurement and recording of traffic Forecasting of traffic Determination of the number of circuits in manual oDeration E. 1 OO-E.229 E.230-E.299 E.300-E.329 E.330-E.399 E.400-E.489 E.400-E.409 E.410-E.419 E.420-E.489 E.490-E.799 E.490-ES05 E.506-ES09 E.510-ES19 Grade of service Defi
6、nitions ISDN traffic engineering Mobile network traffic engineering QUALITY OF TELECOMMUNICATION SERVICES: CONCEPTS, MODELS, OBJECTIVES AND DEPENDABILITY PLANNING Terms and definitions related to the quality of telecommunication services Models for telecommunication services Objectives for quality o
7、f service and related concepts of telecommunication services Use of quality of service objectives for planning of telecommunication networks Field data collection and evaluation on the performance of equipment, networks and services E.540-ES99 E.600-E.699 E.700-E.749 E.750-E.799 E.800-E. 899 E. 800-
8、E. 809 E. 8 1 0-E. 844 E.845-E.859 E. 860-E. 879 E.880-E.899 For further details, please refer to ITU-T List of Recommendations. STD-ITU-T RECMN E-527-ENGL 1977 D 48b257L Ob38802 4TT ITU-T RECOMMENDATION E.529 NETWORK DIMENSIONING USING END-TO-END GOS OBJECTIVES Summary This Recommendation contains
9、the network dimensioning guidelines for circuit-switched networks using end-to-end GOS objectives. The dimensioning methods for networks with fixed traffic routing, time-dependent traffic routing, state- dependent trafc routing and event-dependent traffic routing are described. Source IT-T Recommend
10、ation ES29 was prepared by IT-T Study Group 2 (1997-2000) and was approved under the WTSC Resolution No. 1 procedure on the 26th of May 1997. Recommendation E.529 (0997) 1 STD-ITU-T RECMN E.529-ENGL 1777 D 4862571 0638803 33b FOREWORD ITU (International Telecommunication Union) is the United Nations
11、 Specialized Agency in the field of telecommuni- cations. The IT Telecommunication Standardization Sector (ITU-T) is a permanent organ of the IT. The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommu
12、nications on a worldwide basis. The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics. The approval of Recommendations by the Members of the
13、 IT-T is covered by the procedure laid down in WTSC Resolution No. 1. 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. NOTE In this Recommendation, the expression “Administration“ is used for con
14、ciseness to indicate both a telecommunication administration and a recognized operating agency. INTELLECTUAL PROPERTY RIGHTS The IT draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. The ITU take
15、s no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by IT members or others outside of the Recommendation development process. As of the date of approval of this Recommendation, the ITU hadhad not received notice of intellectual
16、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 the TSB patent database. O IT 1997 All rights reserved. No part of this publicati
17、on may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the IT. 11 Recommendation ES29 (0997) STD-ITU-T RECMN E.529-ENGL 1997 D 4b2591 Ob3880Li 272 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 CONTENTS
18、 Scope of this Recommendation References Terms and definitions . Abbreviations . Introduction 5.1 5.2 Overview of network operation Outline of this Recommendation Categories of routing methods . 6.2 Time-dependent routing methods . 6.3 State-dependent routing methods 6.4 Event-dependent routing meth
19、ods Network dimensioning elements End-to-end GOS objectives 6.1 Fixed routing methods Modelling of offered traffic . 9.1 Traffic variables 9.2 Models for variations in trafc load . Principles of network dimensioning methods 10.1 Basic iterative procedure Principle of the fixed point model 10.2 10.3
20、Use of implied cost and shadow price for network dimensioning Network dimensioning methods for fixed routing networks 11.1 Blocking calculation methods . Determination of design variables 12.1 Blocking calculation methods . Determination of design variables 13.1 Blocking calculation methods . Determ
21、ination of design variables 14.1 Blocking calculation methods . Determination of design variables . 11.2 Network dimensioning methods for time-dependent routing networks . 12.2 Network dimensioning methods for state-dependent routing networks . 13.2 Network dimensioning methods for event-dependent r
22、outing networks . 14.2 History Bibliography . Annex A . Network forecasting and network servicing methods for dynamic routing networks A.l Introduction A.2 Forecasting methods for time-dependent routing networks A.3 A.4 Servicing methods Forecasting methods for state-dependent and event-dependent ro
23、uting networks . Recommendation E.529 (05197) Page 1 1 1 2 3 3 5 5 5 6 6 7 7 8 9 9 9 11 11 12 12 13 14 16 16 16 16 16 16 17 17 17 17 17 17 20 20 22 23 23 . 111 STDmITU-T RECMN E-529-ENGL 1997 W 48b2591 Ub38805 109 Annex B . Example methods for time-dependent routing networks . Annex C . Example meth
24、od for state-dependent routing networks C.l Network model considered . C.2 Blocking probabilities evaluation . C.3 Dimensioning C.4 Extension to event-dependent routing networks . Annex D - Example method for event-dependent routing networks D.l Network model considered . D.2 Implied costs method D.
25、3 Multi-hour network dimensioning using shadow prices . Page 24 29 29 29 31 33 33 33 34 35 iv Recommendation E.529 (0997) STD-ITU-T RECMN E-529-ENGL 1977 m 48b2591 Ob3880b 045 9 Recommendation E.529 NETWORK DIMENSIONING USING END-TO-END GO$ OBJECTIVES (Geneva, 1997) 1 Scope of this Recommendation Th
26、is Recommendation is intended to provide network dimensioning guidelines for circuit-switched networks enabling the network operator to meet end-to-end GOS objectives from the user-plane perspective. Traffic engineering methods for network dimensioning will be presented in this Recommendation. Netwo
27、rk dimensioning guidelines fiom the control-plane perspective are treated in other E-Series Recommendations. Transmission network design is beyond the scope of this Recommendation. 2 References The following IT-T Recommendations and references contain provisions which, through reference in this text
28、, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; all users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent editio
29、n of the Recommendations and other references listed below. A list of the currently valid IT-T Recommendations is regularly published. - - - - - - - - - CCITT Recommendation E. 170 (1992), Trafic routing. IT-T Recommendation E.301 (1993), Impact of non-voice applications on the telephone network. IT
30、-T Recommendation E.412 (1996), Network management controls. CCITT Recommendation ES00 (1 992), Trafic intensity measurement principles. IT-T Recommendation ES01 (1997), Estimation of trafic offered in the network. CCITT Recommendation ES23 (1988), Standard trafic projles for international trafic st
31、reams. CCITT Recommendation ES24 (1 992), Overflow approximations for non-random inputs. CCITT Recommendation ES25 (1992), Designing networks to control grade of service. ITU-T Recommendation ES26 (1993), Dimensioning a circuit group with multi-slot bearer services and no overflow inputs. IT-T Recom
32、mendation ES27 (1995), Dimensioning at a circuit group with multi-slot bearer services and overflow trafic. CCITT Recommendation E.721 (1991), Network grade of service parameters and target values for circuit-switched services in the evolving ISDN. - - 3 Terms and definitions This Recommendation def
33、ines the following terms. 3.1 node: A switching centre or a hypothetical switching centre representing a network. 3.2 circuit group: A group of circuits which is engineered as a unit. See Figure 3-1. 3.3 traffic stream: A class of calls with the same traffic characteristics. 3.4 0-D pair: An origina
34、ting node to destination node pair for a given traffic stream. Recommendation E.529 (0997) 1 STD.ITU-T RECMN E.529-ENGL 1997 m clb259L b38807 T8L 3.5 concerned. end-to-end GOS: Overall GOS of a traffic stream quantified between its O-D pair defined in the network 3.6 route: A concatenation of circui
35、t groups providing a connection between an O-D pair. See Figure 3-1. 3.7 route set: A set of routes connecting the same O-D pair. See Figure 3-1. 3.8 routing pattern: A route set and rules to select one route out of the set for a trafc stream. A B Circuit group a O Route A C B O - rn Route set T0206
36、340-97/d01 A Figure 3-1m.529 - Terminology 4 Abbreviations This Recommendation uses the following abbreviations: m ARR ECCS EDR GOS LLR N-ISDN PSTN SDR TDR 2 Automatic Alternative Routing Automatic Rerouting Economic Hundred Call Seconds Event-Dependent Routing Grade of Service Least Loaded Routing
37、Narrow-band Integrated Services Digital Network Public Switched Telephone Network State-Dependent Routing Time-Dependent Routing Recommendation ES29 (05/97) STD.ITU-T RECMN E.529-ENGL 1997 m qAb2591 Ob3B08 918 D 5 Introduction PSTN and N-ISDN support switched point-to-point bearer connections and pr
38、ovide on-demand bearer services. in such a circuit-switched network, a call is routed, according to traffic routing rules used in the network, from its originating node to destination node in the network. Routing structures, routing schemes, and route selection for traffic routing are described in R
39、ecommendation E.170. There are various traffic routing methods available, from fixed to flexible methods. The traffic routing methods, together with network capacity and other traffic control mechanisms, such as service protection methods, provide an end-to-end GOS for each traffic stream in the net
40、work. Recommendation ES25 describes available service protection methods and provides guidelines for applications of the methods. The purpose of this Recommendation is to present network dimensioning methods that are applicable to networks with routing and traffic control methods. This Recommendatio
41、n focuses on end-to-end call blocking probability as the GOS parameter that is taken into account in the network dimensioning process, and on traffic modelling techniques and methods available for computing end-to-end call blocking probabilities. Further, this Recommendation focuses on non- hierarch
42、ical routing, considering that end-to-end GOS criteria are usually applied in non-hierarchical routing, irrespective of network architectures. The definition of hierarchical and non-hierarchical routing is given in 2.1E.170. This issue of this Recommendation gives example dimensioning methods for a
43、network in which a single routing scheme is used. Dimensioning methods for a network in which multiple routing schemes are interworked are for further study. 5.1 Overview of network operation For network engineering purposes, a network that provides a circuit-switched service is often represented by
44、 a network model which comprises switching nodes interconnected by circuit groups. A circuit group is of either the one-way or both-way type. Figure 5-1 gives an example of a network. Figure 5-2 illustrates a model for the overall architecture of network operations. The central box represents a netw
45、ork, which can have various configurations, and the traffic routing tables within the network. Network configurations include metropolitan area networks, national intercity networks, and global international networks, which support both hierarchical and non-hierarchical routing and mixes of the two.
46、 Routing and network management ensure that performance objectives are met under all conditions including load shifts and failures, and network servicing and network forecasting ensure that network dimensioning meets performance objectives at minimum cost. Figure 5-2 illustrates network management,
47、network servicing and network forecasting as interacting feedback loops around the network. The input driving the network is a stochastic traffic load, consisting of predictable average demand components added to unknown forecast error and load variation components. The feedback controls regulate th
48、e grade of service provided by the network through capacity and routing adjustments. Network management provides for real-time monitoring of network performance through collection and display of real- time traffic and performance data, and allows traffic controls, such as code blocking, call gapping
49、, and re-route controls, to be inserted when circumstances warrant. Network management also allows routing management which takes account of the capacity provided by network servicing and network forecasting, and on a real-time basis adjusts routing patterns as necessary to correct service problems. The updated routing patterns are sent to the switching nodes either directly or via an automated routing management system. Network forecasting accounts for both the current network and the forecast loads in planning network changes, and then network servicing make
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