1、 INTERNATIONAL TELECOMMUNICATION UNION ITU-T E.360.6TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (05/2002) SERIES E: OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS International routing plan QoS routing and related traffic engineering methods Capacity management
2、 methods ITU-T Recommendation E.360.6 ITU-T E-SERIES RECOMMENDATIONS OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS INTERNATIONAL OPERATION Definitions E.100E.103 General provisions concerning Administrations E.104E.119 General provisions concerning users E.120E.13
3、9 Operation of international telephone services E.140E.159 Numbering plan of the international telephone service E.160E.169 International routing plan E.170E.179 Tones in national signalling systems E.180E.189 Numbering plan of the international telephone service E.190E.199 Maritime mobile service a
4、nd public land mobile service E.200E.229 OPERATIONAL PROVISIONS RELATING TO CHARGING AND ACCOUNTING IN THE INTERNATIONAL TELEPHONE SERVICE Charging in the international telephone service E.230E.249 Measuring and recording call durations for accounting purposes E.260E.269 UTILIZATION OF THE INTERNATI
5、ONAL TELEPHONE NETWORK FOR NON-TELEPHONY APPLICATIONS General E.300E.319 Phototelegraphy E.320E.329 ISDN PROVISIONS CONCERNING USERS E.330E.349 INTERNATIONAL ROUTING PLAN E.350E.399 NETWORK MANAGEMENT International service statistics E.400E.409 International network management E.410E.419 Checking th
6、e quality of the international telephone service E.420E.489 TRAFFIC ENGINEERING Measurement and recording of traffic E.490E.505 Forecasting of traffic E.506E.509 Determination of the number of circuits in manual operation E.510E.519 Determination of the number of circuits in automatic and semi-autom
7、atic operation E.520E.539 Grade of service E.540E.599 Definitions E.600E.649 Traffic engineering for IP-networks E.650E.699 ISDN traffic engineering E.700E.749 Mobile network traffic engineering E.750E.799 QUALITY OF TELECOMMUNICATION SERVICES: CONCEPTS, MODELS, OBJECTIVES AND DEPENDABILITY PLANNING
8、 Terms and definitions related to the quality of telecommunication services E.800E.809 Models for telecommunication services E.810E.844 Objectives for quality of service and related concepts of telecommunication services E.845E.859 Use of quality of service objectives for planning of telecommunicati
9、on networks E.860E.879 Field data collection and evaluation on the performance of equipment, networks and services E.880E.899 For further details, please refer to the list of ITU-T Recommendations. ITU-T Rec. E.360.6 (05/2002) i ITU-T Recommendation E.360.6 QoS routing and related traffic engineerin
10、g methods Capacity management methods Summary The E.360.x series of Recommendations describes, analyses, and recommends methods which control a networks response to traffic demands and other stimuli, such as link failures or node failures. The functions discussed and recommendations made related to
11、traffic engineering (TE) are consistent with the definition given in the Framework document of the Traffic Engineering Working Group (TEWG) within the Internet Engineering Task Force (IETF): Internet Traffic Engineering is concerned with the performance optimization of operational networks. It encom
12、passes the measurement, modelling, characterization, and control of Internet traffic, and the application of techniques to achieve specific performance objectives, including the reliable and expeditious movement of traffic through the network, the efficient utilization of network resources, and the
13、planning of network capacity. The methods addressed in the E.360.x series include call and connection routing, QoS resource management, routing table management, dynamic transport routing, capacity management, and operational requirements. Some of the methods proposed herein are also addressed in, o
14、r are closely related to those proposed in ITU-T Recs E.170 to E.179 and E.350 to E.353 for routing, E.410 to E.419 for network management and E.490 to E.780 for other traffic engineering issues. The recommended methods are meant to apply to IP-based, ATM-based, and TDM-based networks, as well as th
15、e interworking between these network technologies. Essentially, all of the methods recommended are already widely applied in operational networks worldwide, particularly in PSTN networks employing TDM-based technology. However, these methods are shown to be extensible to packet-based technologies, t
16、hat is, to IP-based and ATM-based technologies, and it is important that networks which evolve to employ these packet technologies have a sound foundation of methods to apply. Hence, it is the intent that the methods recommended in this series of Recommendations be used as a basis for requirements f
17、or specific methods, and, as needed, for protocol development in IP-based, ATM-based, and TDM-based networks to implement the methods. The methods encompassed in this Recommendation include traffic management through control of routing functions, which include QoS resource management. Results of ana
18、lysis models are presented which illustrate the tradeoffs between various approaches. Based on the results of these studies, as well as established practice and experience, methods are recommended for consideration in network evolution to IP-based, ATM-based, and/or TDM-based technologies. Source IT
19、U-T Recommendation E.360.6 was prepared by ITU-T Study Group 2 (2001-2004) and approved under the WTSA Resolution 1 procedure on 16 May 2002. ii ITU-T Rec. E.360.6 (05/2002) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunic
20、ations. The ITU Telecommunication Standardization Sector (ITU-T) is a 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 Telecommunicat
21、ion Standardization Assembly (WTSA), which meets every four years, establishes 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 in
22、formation technology which fall within ITU-Ts purview, the necessary standards 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 a
23、gency. 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, validity or applicability of claimed Intellectual Propert
24、y 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 required to implement this Recommendation. However, imple
25、mentors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the 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.
26、E.360.6 (05/2002) iii CONTENTS Page 1 Scope 1 2 References. 1 3 Definitions 2 4 Abbreviations 2 5 Link capacity design models 2 6 Shortest path selection models . 3 7 Multihour network design models 3 7.1 Discrete Event Flow Optimization (DEFO) models 5 7.2 Traffic Load Flow Optimization (TLFO) mode
27、ls 8 7.3 Virtual Trunking Flow Optimization (VTFO) models. 10 8 Day-to-day load variation design models. 10 9 Forecast uncertainty/reserve capacity design models. 11 10 Meshed, sparse, and dynamic-transport design models 12 11 Conclusions/recommendations. 14 Annex A Modelling of traffic engineering
28、methods. 15 A.1 Per-virtual-network vs. per-flow network design. 15 A.2 Integrated vs. separate voice/ISDN and data network designs. 16 A.3 Multilink vs. 2-link network design . 21 A.4 Single-area flat vs. 2-level hierarchical network design 21 A.5 EDR vs. SDR network design 23 A.6 Dynamic transport
29、 routing vs. fixed transport routing network design 25 iv ITU-T Rec. E.360.6 (05/2002) Introduction In this Recommendation we discuss capacity management principles, as follows: Link Capacity Design Models. These models find the optimum tradeoff between traffic carried on a shortest network path (pe
30、rhaps a direct link) versus traffic carried on alternate network paths. Shortest Path Selection Models. These models enable the determination of shortest paths in order to provide a more efficient and flexible routing plan. Multihour Network Design Models. Three models are described including: i) di
31、screte event flow optimization (DEFO) models; ii) traffic load flow optimization (TLFO) models; and iii) virtual trunking flow optimization (VTFO) models. Day-to-day Load Variation Design Models. These models describe techniques for handling day-to-day variations in capacity design. Forecast Uncerta
32、inty/Reserve Capacity Design Models. These models describe the means for accounting for errors in projecting design traffic loads in the capacity design of the network. See ITU-T Recs E.520 to E.529 and E.731 on dimensioning of TDM networks; E.735 and E.737 on dimensioning of ATM networks; E.733 on
33、dimensioning of SS7 signalling networks and E.734 on dimensioning of IN network resources. ITU-T Rec. E.360.6 (05/2002) 1 ITU-T Recommendation E.360.6 QoS routing and related traffic engineering methods Capacity management methods 1 Scope The E.360.x series of Recommendations describes, analyses, an
34、d recommends methods which control a networks response to traffic demands and other stimuli, such as link failures or node failures. The functions discussed and recommendations made related to traffic engineering (TE) are consistent with the definitions given in the Framework document of the Traffic
35、 Engineering Working Group (TEWG) within the Internet Engineering Task Force (IETF): Internet Traffic Engineering is concerned with the performance optimization of operational networks. It encompasses the measurement, modelling, characterization, and control of Internet traffic, and the application
36、of techniques to achieve specific performance objectives, including the reliable and expeditious movement of traffic through the network, the efficient utilization of network resources, and the planning of network capacity. The methods addressed in the E.360.x series include call and connection rout
37、ing, QoS resource management, routing table management, dynamic transport routing, capacity management, and operational requirements. Some of the methods proposed herein are also addressed in, or are closely related to, those proposed in ITU-T Recs E.170 to E.179 and E.350 to E.353 for routing, E.41
38、0 to E.419 for network management and E.490 to E.780 for other traffic engineering issues. The recommended methods are meant to apply to IP-based, ATM-based, and TDM-based networks, as well as the interworking between these network technologies. Essentially, all of the methods recommended are alread
39、y widely applied in operational networks worldwide, particularly in PSTN networks employing TDM-based technology. However, these methods are shown to be extensible to packet-based technologies, that is, to IP-based and ATM-based technologies, and it is important that networks which evolve to employ
40、these packet technologies have a sound foundation of methods to apply. Hence, it is the intent that the methods recommended in this series of Recommendations be used as a basis for requirements for specific methods, and, as needed, for protocol development in IP-based, ATM-based, and TDM-based netwo
41、rks to implement the methods. Hence the methods encompassed in this series of Recommendations include: traffic management through control of routing functions, which include call routing (number/name translation to routing address), connection routing, QoS resource management, routing table manageme
42、nt, and dynamic transport routing. capacity management through control of network design, including routing design. operational requirements for traffic management and capacity management, including forecasting, performance monitoring, and short-term network adjustment. Results of analysis models ar
43、e presented which illustrate the tradeoffs between various approaches. Based on the results of these studies, as well as established practice and experience, TE methods are recommended for consideration in network evolution to IP-based, ATM-based, and/or TDM-based technologies. 2 References See clau
44、se 2 of ITU-T Rec. E.360.1. 2 ITU-T Rec. E.360.6 (05/2002) 3 Definitions See clause 3 of ITU-T Rec. E.360.1. 4 Abbreviations See clause 4 of ITU-T Rec. E.360.1. 5 Link capacity design models As illustrated in Figure 1, link capacity design requires a tradeoff of the traffic load carried on the link
45、and traffic that must route on alternate paths. E.360.6_F1Direct A-B link capacityAlternate path costNetworkcostTotal network costdirect path costOverflowtrafficA-B Direct traffic CABn*Figure 1/E.360.6 Tradeoff between direct link capacity and alternate path capacity High link occupancy implies more
46、 efficient capacity utilization, however high occupancy leads to link congestion and the resulting need for some traffic not to be routed on the direct link but on alternate paths. Alternate paths may entail longer, less efficient paths. A good balance can be struck between link capacity design and
47、alternate path utilization. For example, consider Figure 1 which illustrates a network where traffic is offered on link A-B connecting node A and node B. Some of the traffic can be carried on link A-B, however, when the capacity of link A-B is exceeded, some of the traffic must be carried on alterna
48、te paths or be lost. The objective is to determine the direct A-B link capacity and alternate routing path flow such that all the traffic is carried at minimum cost. A simple optimization procedure is used to determine the best proportion of traffic to carry on the direct A-B link and how much traff
49、ic to alternate route to other paths in the network. As the direct link capacity is increased, the direct link cost increases while the alternate path cost decreases as more direct capacity is added, because the overflow load decreases and therefore the cost of carrying the overflow load decreases. An optimum, or minimum, cost condition is achieved when the direct A-B link capacity is increased to the point where the cost per incremental unit of bandwidth capacity to carry traffic on the direct link is just equal to the cost per unit of band
