1、 INTERNATIONAL TELECOMMUNICATION UNION ITU-T E.360.3TELECOMMUNICATION 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 QoS resource manage
2、ment methods ITU-T Recommendation E.360.3 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.120
3、E.139 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 servi
4、ce and 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 INTER
5、NATIONAL 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 Checkin
6、g the 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-a
7、utomatic 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 PLAN
8、NING 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 telecommuni
9、cation 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.360.3 (05/2002) i ITU-T Recommendation E.360.3 QoS routing and related traffic engine
10、ering methods QoS resource management methods Summary The E.360.x series of Recommendations describes, analyzes, 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 rel
11、ated to 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.
12、It encompasses 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,
13、and the 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 address
14、ed 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.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 wel
15、l as the 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 technolog
16、ies, that 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 requirem
17、ents for 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
18、of analysis 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. Sour
19、ce ITU-T Recommendation E.360.3 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.360.3 (05/2002) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecom
20、munications. 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 Telecommu
21、nication 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
22、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 Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operat
23、ing agency. 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 Pr
24、operty 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,
25、implementors 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
26、Rec. E.360.3 (05/2002) iii CONTENTS Page 1 Scope 1 2 References. 1 3 Definitions 2 4 Abbreviations 2 5 Class-of-service identification, policy-based routing table derivation and QoS resource management steps 2 5.1 Class-of-Service identification . 2 5.2 Policy-based routing table derivation. 2 5.3 Q
27、oS resource management steps 4 6 Dynamic bandwidth allocation, protection, and reservation principles . 5 7 Per-virtual-network bandwidth allocation, protection, and reservation . 7 7.1 Per-VNET bandwidth allocation/reservation Meshed network case. 10 7.2 Per-VNET bandwidth allocation/reservation Sp
28、arse network case. 13 8 Per-flow bandwidth allocation, protection, and reservation. 15 8.1 Per-flow bandwidth allocation/reservation Meshed network case 15 8.2 Per-Flow bandwidth allocation/reservation Sparse network case. 17 9 Packet-level traffic control . 18 10 Other QoS resource management const
29、raints. 20 11 Interdomain QoS resource management. 20 12 Conclusions/recommendations. 22 Annex A Modelling of traffic engineering methods. 22 A.1 Performance of bandwidth reservation methods 22 A.2 Multiservice network performance: Per-VNET vs. Per-flow bandwidth allocation 24 A.3 Multiservice netwo
30、rk performance: single-area flat topology vs. Multi-area 2-level hierarchical flat topology 26 A.4 Multiservice network performance: Need for MPLS and DiffServ . 28 iv ITU-T Rec. E.360.3 (05/2002) Introduction QoS resource management (sometimes called QoS routing) functions include class-of-service
31、identification, routing table derivation, connection admission, bandwidth allocation, bandwidth protection, bandwidth reservation, priority routing, priority queuing, and other related resource management functions. A broad classification of these functions is as follows: 1) connection-level control
32、s: provide the required connection-level GoS objectives in an economical way; 2) packet-level controls: ensure the required packet-level GoS objectives. Connection-level controls are discussed in clauses 5 to 8, and packet level controls are discussed in clause 9. QoS resource management methods hav
33、e been applied successfully in TDM-based networks A98, and are being extended to IP-based and ATM-based networks. In an illustrative QoS resource management method, bandwidth is allocated in discrete changes to each of several virtual networks (VNETs), which are each assigned a priority correspondin
34、g to either high-priority key services, normal-priority services, or best-effort low-priority services. Examples of services within these VNET categories include: high-priority key services such as defense voice communication; normal-priority services such as constant rate, interactive, delay-sensit
35、ive voice; variable rate, interactive, delay-sensitive IP-telephony; and variable rate, non-interactive, non-delay-sensitive WWW file transfer; and low-priority best-effort services such as variable rate, non-interactive, non-delay-sensitive voice mail, email, and file transfer. Bandwidth changes in
36、 VNET bandwidth capacity can be determined by edge nodes on a per-flow (per-connection) basis, or based on an overall aggregated bandwidth demand for VNET capacity (not on a per-connection demand basis). In the latter case of per-VNET bandwidth allocation, based on the aggregated bandwidth demand, e
37、dge nodes make periodic discrete changes in bandwidth allocation, that is, either increase or decrease bandwidth, such as on the constraint-based routing label switched paths (CRLSPs) constituting the VNET bandwidth capacity. In the illustrative QoS resource management method, which we assume is MPL
38、S-based, the bandwidth allocation control for each VNET CRLSP is based on estimated bandwidth needs, bandwidth use, and status of links in the CRLSP. The edge node, or originating node (ON), determines when VNET bandwidth needs to be increased or decreased on a CRLSP, and uses an illustrative MPLS C
39、RLSP bandwidth modification procedure to execute needed bandwidth allocation changes on VNET CRLSPs. In the bandwidth allocation procedure the constraint-based routing label distribution protocol (CRLDP) J00 or the resource reservation protocol (RSVP-TE) AGBLSS00 could be used, for example, to speci
40、fy appropriate parameters in the label request message: a) to request bandwidth allocation changes on each link in the CRLSP; and b) to determine if link bandwidth can be allocated on each link in the CRLSP. If a link bandwidth allocation is not allowed, a notification message with an illustrative c
41、rankback parameter allows the ON to search out possible bandwidth allocation on another CRLSP. In particular, we illustrate an optional depth-of-search (DoS) parameter in the label request message to control the bandwidth allocation on individual links in a CRLSP. In addition, we illustrate an optio
42、nal modify parameter in the label request message to allow dynamic modification of the assigned traffic parameters (such as peak data rate, committed data rate, etc.) of an already existing CRLSP. Finally, we illustrate a crankback parameter in the notification message to allow an edge node to searc
43、h out additional alternate CRLSPs when a given CRLSP cannot accommodate a bandwidth request. ITU-T Rec. E.360.3 (05/2002) v QoS resource management therefore can be applied on a per-flow (or per-call or per-connection-request) basis, or can be beneficially applied to traffic trunks (also known as “b
44、andwidth pipes“ or “virtual trunking“) in the form of CRLSPs in IP-based networks or SVPs in ATM-based networks. QoS resource management provides integration of services on a shared network, for many classes-of-service such as: CBR services including voice, 64-, 384-, and 1536-kbit/s N-ISDN switched
45、 digital data, international switched transit, priority defense communication, virtual private network, 800/free-phone, fiber preferred, and other services. Real-time VBR services including IP-telephony, compressed video, and other services. Non-real-time VBR services including WWW file transfer, cr
46、edit card check, and other services. UBR services including voice mail, email, file transfer, and other services. We now illustrate the principles of QoS resource management, which includes integration of many traffic classes, as discussed above. ITU-T Rec. E.360.3 (05/2002) 1 ITU-T Recommendation E
47、.360.3 QoS routing and related traffic engineering methods QoS resource management methods 1 Scope The E.360.x series of Recommendations describes, analyzes, and recommends methods which control a networks response to traffic demands and other stimuli, such as link failures or node failures. The fun
48、ctions discussed and recommendations made related to traffic engineering (TE) are consistent with the definitions given in the Framework document of the Traffic Engineering Working Group (TWG) within the Internet Engineering Task Force (IETF): Internet Traffic Engineering is concerned with the perfo
49、rmance optimization of operational networks. It encompasses 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 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 tran
