1、 INTERNATIONAL TELECOMMUNICATION UNION ITU-T E.361TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (05/2003) SERIES E: OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS International routing plan QoS routing support for interworking of QoS service classes across routin
2、g technologies ITU-T Recommendation E.361 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.361 (05/2003) i ITU-T Recommendation E.361 QoS routing support for interworking of Qo
10、S service classes across routing technologies Summary ITU-T Rec. E.360.1, “Framework for QoS routing and related traffic engineering methods for IP-, ATM-, and TDM-based multiservice networks“, provides a framework for QoS Service Classes (QSCs), called virtual networks (VNETs) in the E.360.x series
11、. QSCs are defined as aggregations of individual service classes. Instead of having per-class parameters being configured and propagated on each network interface, classes are aggregated into QSCs having common per-QSC parameters (e.g., maximum bandwidth) to satisfy required performance levels. QSCs
12、 are known as VNETs in TDM networks, class types in IP/MPLS/DiffServ networks, and QoS classes in ATM networks. In this Recommendation we identify QoS routing functions and associated parameters, which include: a) bandwidth allocation/protection, with traffic and QoS parameters; b) routing priority;
13、 c) queuing priority; and d) class-of-service identification, with service identity and QSC/VNET parameters. We propose means of signalling these QoS routing parameters across networks employing different routing technologies, including IP-, ATM-, and TDM-based routing technologies. We propose exten
14、sions to signalling protocols such as SIP and RSVP-TE to support signalling of QSCs within and across networks. Source ITU-T Recommendation E.361 was prepared by ITU-T Study Group 2 (2001-2004) and approved under the WTSA Resolution 1 procedure on 2 May 2003. ii ITU-T Rec. E.361 (05/2003) FOREWORD T
15、he 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 studying technical, operating and tariff questions and issuing Re
16、commendations 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 groups which, in turn, produce Recommendations on these topics. T
17、he 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 with ISO and IEC. NOTE In this Recommendation, the expression “Admi
18、nistration“ 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 Recommendation may involve the use of a claimed Intellectual Prop
19、erty 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 of approval of this Recommendation, ITU had not received notice of
20、 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 the TSB patent database. ITU 2003 All rights reserved. No part of t
21、his publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. ITU-T Rec. E.361 (05/2003) iii CONTENTS Page 1 Introduction 1 2 Scope 2 3 Definitions 2 4 References. 5 5 Abbreviations 6 6 QoS routing functions and parameters associated with QoS service classe
22、s . 8 7 Signalling of QoS routing information within and across networks 9 7.1 Application/Call control . 9 7.2 Vertical control. 9 7.3 Bearer control . 10 7.4 Proposed signalling protocol extensions 10 8 Example of internetwork QoS routing and signalling 12 Bibliography. 15 ITU-T Rec. E.361 (05/200
23、3) 1 ITU-T Recommendation E.361 QoS routing support for interworking of QoS service classes across routing technologies 1 Introduction Current and future networks are rapidly evolving to carry a multitude of voice/ISDN services and packet data services on Internet Protocol (IP), asynchronous transfe
24、r mode (ATM), and time division multiplexing (TDM) networks. QoS routing is an indispensable network function which controls a networks response to traffic demands and other stimuli, such as network failures. QoS routing encompasses traffic management through control of routing functions, which incl
25、ude number/name translation to routing address, connection routing, routing table management, and QoS resource management. To support the ability to carry all types of telecommunications traffic (voice, data, video, etc.) over a single network, networks are evolving beyond best effort capabilities t
26、o provide a variety of performance and reliability options. Transport backbones are incorporating new optical technologies enabling flexible and cost-effective solutions for carrying various grades of telecommunications traffic. It is important for service providers to satisfy customer expectations
27、for end-to-end reliability and QoS, for all types of transactions and services. QoS requirements include performance parameters such as delay, jitter, packet loss, etc, and are related to the type of transaction (e.g., voice, data, video). Reliability on the other hand represents expectations on ade
28、quate service availability over a specified period for the desired transaction types, and these expectations are typically negotiated in Service Level Agreements (SLA). Further, services may have different reliability expectations depending on the type of service. For example, a voice over IP (VoIP)
29、 packet stream for emergency services calls would require high priority reliability treatment. Other VoIP services may have lower reliability expectations and hence their network reliability treatment may be less stringent. To satisfy reliability and QoS considerations for all transaction and servic
30、e types, a service provider needs to ensure that all network protocol layers are equipped to recognize and satisfy the QoS and reliability requirements for the service classes. ITU-T Rec. E.360.1, “Framework for QoS routing and related traffic engineering methods for IP-, ATM-, and TDM-based multise
31、rvice networks,“ provides a framework for QoS Service Classes (QSCs), called virtual networks (VNETs) in the E.360.x series. QSCs are defined as aggregations of individual service classes. Instead of having per-class parameters being configured and propagated on each network interface, classes are a
32、ggregated into QSCs having common per-QSC parameters (e.g., maximum bandwidth) to satisfy required performance levels. There is no maximum or minimum bandwidth requirement to be enforced at the level of individual class in the QSC. QSCs are known as VNETs in TDM networks, class types in IP/MPLS/Diff
33、Serv networks, and QoS classes in ATM networks. In this Recommendation we identify QoS routing functions and associated parameters, which include: a) bandwidth allocation/protection, with traffic and QoS parameters; b) routing priority; c) queuing priority; and d) class-of-service identification, wi
34、th service identity and QSC/VNET parameters. 2 ITU-T Rec. E.361 (05/2003) We propose means of signalling these QoS routing parameters across networks employing different routing technologies, including IP-, ATM-, and TDM-based routing technologies. We propose extensions to signalling protocols such
35、as SIP and RSVP-TE to support signalling of QoS routing parameters within and across networks. Clause 6 summarizes the QoS routing functions and associated parameters. Clause 7 describes proposed means for signalling QoS routing information within protocols such as SIP and RSVP-TE. We discuss necess
36、ary signalling and information exchange requirements to enable the QoS routing functions, and to ensure compatibility and inter-working across different types of networks. Clause 8 gives an example of internetwork QoS routing and signalling. 2 Scope This Recommendation identifies QoS routing functio
37、ns and associated parameters associated with QSCs, and proposes means of signalling these parameters across networks employing different routing technologies, including IP-, ATM-, and TDM-based routing technologies, as well as the inter-working between these network technologies. Multi-layer QoS rou
38、ting control functions are identified including: a) application or call control; b) vertical control; and c) bearer control. We also propose extensions to signalling protocols such as SIP and RSVP-TE to support signalling of QSCs within and across networks. The guidance of this Recommendation applie
39、s to QoS routing for individual microflows or for aggregated flows. For QSCs or aggregated flows, this Recommendation applies within networks where an operator can aggregate individual service classes or flows however they wish. However, inter-network aggregation is for further study 3 Definitions T
40、his Recommendation defines the following terms: 3.1 alternate path routing: a routing technique where multiple paths, rather than just the shortest path, between a source node and a destination node are utilized to route traffic, which is used to distribute load among multiple paths in the network.
41、3.2 blocking: refers to the denial or non-admission of a call or connection-request, based for example on the lack of available resources on a particular link (e.g., link bandwidth or queuing resources). 3.3 call: generic term to describe the establishment, utilization, and release of a connection (
42、bearer path) or data flow. 3.4 call routing: number (or name) translation to routing address(es), perhaps involving use of network servers or intelligent network (IN) databases for service processing. 3.5 circuit switching: denotes the transfer of an individual set of bits within a TDM time-slot ove
43、r a connection between an input port and an output port within a given circuit-switching node through the circuit-switching fabric (see “switching“). 3.6 class of service: characteristics of a service such as described by service identity, virtual network, link capability requirements, QoS and traff
44、ic threshold parameters. 3.7 class type: the set of Traffic Trunks crossing a link that is governed by a specific set of bandwidth constraints. Class type is used for the purposes of link bandwidth allocation, constraint based routing, and admission control. A given Traffic Trunk belongs to the same
45、 class type on all links. ITU-T Rec. E.361 (05/2003) 3 3.8 connection: bearer path, label switched path, virtual circuit, and/or virtual path established by call routing and connection routing. 3.9 connection admission control: a process by which it is determined whether a link or a node has suffici
46、ent resources to satisfy the QoS required for a connection or flow. CAC is typically applied by each node in the path of a connection or flow during set-up to check local resource availability. 3.10 connection routing: connection establishment through selection of one path from path choices governed
47、 by the routing table. 3.11 crankback: a technique where a connection or flow set-up is backtracked along the call/connection/flow path up to the first node that can determine an alternative path to the destination node. 3.12 destination node: terminating node within a given network. 3.13 flow: bear
48、er traffic associated with a given connection or connectionless stream having the same originating node, destination node, class of service, and session identification. 3.14 GoS (grade of service): a number of network design variables used to provide a measure of adequacy of a group of resources und
49、er specified conditions (e.g., GoS variables may be probability of loss, dial tone delay, etc.). 3.15 GoS standards: parameter values assigned as objectives for GoS variables. 3.16 integrated services: a model which allows for integration of services with various QoS classes, such as key-priority, normal-priority, and best-effort priority services. 3.17 link: a bandwidth transmission medium between nodes that is engineered as a unit. 3.18 logical link: a bandwidth transmission medium of fixed bandwidth (e.g., T1, DS3, OC3, etc.) at the link layer (layer 2)
