1、 International Telecommunication Union ITU-T E.412.1TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (12/2007) SERIES E: OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS Network management International network management Assessing the impact of resource discontinuity
2、 in transport networks on service availability ITU-T Recommendation E.412.1 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
3、 provisions concerning users E.120E.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 servic
4、e E.190E.199 Maritime mobile service 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
5、.260E.269 UTILIZATION OF THE INTERNATIONAL 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.404 International net
6、work management E.405E.419 Checking 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 o
7、f circuits in automatic and semi-automatic 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,
8、 OBJECTIVES AND DEPENDABILITY PLANNING 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 obje
9、ctives for planning of telecommunication networks E.860E.879 Field data collection and evaluation on the performance of equipment, networks and services E.880E.899 OTHER E.900E.999 For further details, please refer to the list of ITU-T Recommendations. ITU-T Rec. E.412.1 (12/2007) i ITU-T Recommenda
10、tion E.412.1 Assessing the impact of resource discontinuity in transport networks on service availability Summary ITU-T Recommendation E.412.1 provides two indexes for assessing the impact of resource discontinuities in transport networks. These two indexes are called the “service outage index (SOI)
11、“ and the “service affected index (SAI)“ on the availability of services for users. They can be used to guide a network operator to arrange the OAM resources so that better services can be provided. (The word “service“ is used in its normal sense and not as a defined term or defined ITU service). So
12、urce ITU-T Recommendation E.412.1 was approved on 14 December 2007 by ITU-T Study Group 2 (2005-2008) under the ITU-T Recommendation A.8 procedure. Keywords Service affected index, service outage index. ii ITU-T Rec. E.412.1 (12/2007) FOREWORD The International Telecommunication Union (ITU) is the U
13、nited Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). 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 Recomm
14、endations 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. The a
15、pproval 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 “Administ
16、ration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure e.g. interoperability or applicability) and complia
17、nce with the Recommendation is achieved when all of these mandatory provisions are met. The words “shall“ or some other obligatory language such as “must“ and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is
18、required of any party. 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 Inte
19、llectual 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 intellectual property, protected by patents, which may be required to implement this Recommendation
20、. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2008 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without
21、the prior written permission of ITU. ITU-T Rec. E.412.1 (12/2007) iii CONTENTS Page 1 Scope 1 2 References. 1 3 Definitions 1 3.1 Terms defined elsewhere 1 3.2 Terms defined in this Recommendation. 2 4 Abbreviations and acronyms 2 5 Conventions 2 6 Overview of service environments of transport netwo
22、rks 2 6.1 Evolution of transport networks . 2 6.2 Services environment of transport networks 3 7 Assessment indexes for the operational status of transport networks 3 7.1 Conventions for the concept of circuit operational state of a transport network. 3 7.2 Service outage index (SOI) 3 7.3 Service a
23、ffected index 5 8 Failure measuring approach of (O, A, P, R) quaternion . 6 Appendix I Usage examples for assessment indexes 8 I.1 Examples for SOI and SAI applications. 8 I.2 Example of early warning for circuit lines using SOI and SAI 11 iv ITU-T Rec. E.412.1 (12/2007) Introduction The service out
24、age index (SOI) and service affected index (SAI) are defined based on service lost or potential service lost, and these two indexes together can be used to assess the operational status of a transport network from the viewpoint of service lost, where SOI indicates the percentage of service lost comp
25、ared to the total service; while SAI indicates the percentage of affected service (due to protection degradation) compared to the total service. These two indexes can be used when an operator wants to know the overall operational quality of a transport network, and these two indexes together can qua
26、ntitatively express the healthy condition of the transport network. Based on the values of these two indexes, the operator can take measures to provide more reasonable transport resources to provide better services. These two indexes can also be used for early warnings. When there are limited backup
27、 resources for a transport network, by calculating these two indexes with the assumption of each line failure, the operator can find out which line(s) will cause more service loss than others. If some lines with the values exceed a predefined threshold, an early warning message will be sent to the o
28、perator so that they will have a higher priority to be provided with backup measures. These two indexes are mainly calculated based on a network management system, from which the network topology, fault information and service information can be obtained. These two indexes are applicable for all kin
29、ds of network topologies, but the SAI index is not applicable for those transport networks that do not provide protection mechanisms. In other words, a transport network without any protection schemes will have a constant value of SAI. ITU-T Rec. E.412.1 (12/2007) 1 ITU-T Recommendation E.412.1 Asse
30、ssing the impact of resource discontinuity in transport networks on service availability 1 Scope This Recommendation provides an overview of the assessment indicators for the operational status of transport networks with protection schemes. It is the scope of this Recommendation to provide an overvi
31、ew of: The service environments of transport networks for network operational assessment. The assessment of operational status of the transport network for a specific time point, which is used to indicate the robustness of a transport network. The assessment of potential risks for outage of a transp
32、ort network for a specific time point, which is used to indicate the extent of the services affected in a transport network. The quantitive failure measuring approach using the above indexes. 2 References The following ITU-T Recommendations and other references contain provisions which, through refe
33、rence in this 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
34、 recent edition 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. ITU-T G.805 ITU-T
35、Recommendation G.805 (2000), Generic functional architecture of transport networks. ITU-T M.3320 ITU-T Recommendation M.3320 (1997), Management requirements framework for the TMN X-Interface. 3 Definitions 3.1 Terms defined elsewhere This Recommendation uses the following terms defined elsewhere: 3.
36、1.1 customer ITU-T M.3320: An organization which has a business relationship with a service provider for the provision of network services. A customer may encompass one or more end users of telecommunications services. 3.1.2 service provider ITU-T M.3320: A general reference to an entity who provide
37、s telecommunication services to customers and other users either on a tariff or contract basis. A service provider may or may not operate a network. A service provider may or may not be a customer of another service provider. 3.1.3 transport network ITU-T G.805: The functional resources of the netwo
38、rk which conveys user information between locations. 2 ITU-T Rec. E.412.1 (12/2007) 3.2 Terms defined in this Recommendation This Recommendation defines the following terms: 3.2.1 (O, A, P, R) quaternion: SOI and SAI are time-variable, discrete values. Using straight lines to connect successive samp
39、le values, continuous functions of SOI(t) and SAI(t) can be created. Based on SOI(t) and SAI(t), failure measure approach, (O, A, P, R) quaternion are defined where, O: Outage component. It is the component to measure the failures total extent of service lost. A: Affected component. It is the compon
40、ent to measure the failures total extent of potential risk. P: Process component. It is the component to describe failure process. It consists of function curves of SOI(t) and SAI(t) which are drawn in one coordinate system. R: Remark component. It is the component for recording some important neces
41、sary information. 3.2.2 service affected index (SAI): Service affected index, which considers the extent of a transport network being affected, is a metric to measure potential service risks for a certain failure. SAI represents the weight ratio of affected services over total services. 3.2.3 servic
42、e outage index (SOI): Service outage index, which considers the extent of a transport network being destroyed, is a metric to measure actual service losses for a certain failure. SOI represents the weight ratio of lost services over total services. 4 Abbreviations and acronyms This Recommendation us
43、es the following abbreviations and acronyms: ASON Automatically Switched Optical Network DWDM Dense Wavelength Division Multiplexing IP Internet Protocol MAX Maximum MIN Minimum PDH Plesiochronous Digital Hierarchy SAI Service Affected Index SDH Synchronous Digital Hierarchy SOI Service Outage Index
44、 SP Service Provider VIP Very Important Person 5 Conventions None. 6 Overview of service environments of transport networks 6.1 Evolution of transport networks Transport networks are the bases of more and more services, and they provide reliable end-to-end connections (circuits) for service layer ne
45、tworks. Transport networks have been evolving from PDH, SDH to DWDM, and these networks still coexist in current networks. As ASON technology ITU-T Rec. E.412.1 (12/2007) 3 has been developed, more requirements for communication capacity of the transport networks are supposed to be provided. 6.2 Ser
46、vices environment of transport networks Transport networks can be divided into several layer networks, and end-to-end leased circuit services are the most popular services provided to customers, upon which multiple kinds of services can been supported, such as PCM, IP or other data services. With th
47、e evolution of transport networks and all the services that transport networks provide to customers, the relationship between transport networks and service layer networks has become closer. Therefore, the operational quality of transport networks has much more influence on the service-provisioning
48、capabilities of service layers. In order to improve the service level that service providers (SPs) provided to the customer and meet the increasing requirements for communication quality, the operational status should be assessed for SPs to know the extent of the services being, or to be, affected s
49、o that measures may be taken to reduce the service unavailability with a reasonable direction and order. The following clauses describe the detailed indicators for the assessment of the operational status of transport networks, which can be used for early warning for transport network operators. 7 Assessment indexes for the operational status of transport networks 7.1 Conventions for the concept of circuit operational state of a transport network Generally, it is assumed that circuits (in this Recommendation, the concept of c
