1、Report No. 24A A Technical ReportonAugust 1997 Network SurvivabilityPerformance(Supplement to TechnicalReport No. 24)Prepared byT1A1.2Working GrouponNetwork SurvivabilityPerformanceCommittee T1 is sponsored by the Alliance for Telecommunications Industry SolutionsAccredited by the American National
2、Standards InstituteCopyright 1997 by Alliance for Telecommunications IndustrySolutionsAll rights reserved.No part of this publication may be reproduced in any form,in an electronic retrieval system or otherwise, without theprior written permission of the publisher.A Technical ReportonNetwork Surviva
3、bility Performance(Supplement to Technical Report No. 24)AbstractThis supplement to Committee T1 Technical Report No. 24 (TR No. 24) onNetwork Survivability Performance addresses the need for a commonunderstanding and for techniques assessing network survivability. ThisTechnical Report resolves some
4、 of the issues and questions left for further study,and clarifies several TR No. 24 definitions. TR No. 24 emphasizes theclassification of network failures (i.e., identifying whether or not a serviceoutage has occurred) and addresses the quantification of failure events, andtechniques to measure the
5、 severity of the failure. This report also providesimproved measures of failures with respect to service outage severity. Itclassifies the architectures and services of industry segments other than wireline(i.e., wireless, cable TV, and satellite) and provides methods in thecorresponding appendices
6、to calculate outage index values for voicebandtelephony service outages.Document T1A1.2/97-001R3Prepared by T1A1.2Working Group on Network Survivability PerformanceForewordThis supplement to Committee T1 Technical Report No. 24 (TR No. 24) on NetworkSurvivability Performance addresses the concerns f
7、rom the telecommunicationscommunity about the survivability of telecommunications networks and providedservices. It provides a framework that can be used with existing measurements toevaluate outages for a variety of networks (wireline, wireless, cable TV, andsatellite).This Technical Report is inte
8、nded for providers of telecommunications networks andservices, and telecommunications equipment suppliers.Suggestions for enhancement of this report are welcome. These should be sent tothe Alliance for Telecommunications Industry Solutions, Suite 500, 1200 G StreetN.W., Washington, D.C. 20005.Workin
9、g Group T1A1.2 on Network Survivability Performance, which developedthis report, has the following officers and participants:Chair: F. KaudelVice-Chair: S. MakrisEditors:F. Kaudel S. Makris J. BennettActive Participants:J. BennettL. BrownR. CanadayM. DaneshmandV. EmersonR. HaferlR. JensenG. Johnston
10、K. JonesM. KocaturkF. KaudelJ. LordS. MakrisA. McCainA. PupekD. SetzkeL. SzerenyiS. VinayagamurthyR. WalleriTable of Contents0. EXECUTIVE SUMMARY 11. PURPOSE, SCOPE, APPLICATION, AND OUTLINE . 11.1 PURPOSE. 11.2 SCOPE . 11.3 APPLICATION . 11.4 OUTLINE. 12. RELATED WORK . 22.1 COMMITTEE T1 STANDARDS
11、WORK. 22.2 INTERNATIONAL STANDARDS WORK 22.3 OTHER DOMESTIC FORUMS AND COMMITTEES. 23. INTRODUCTION. 34. GOALS AND USES OF QUANTIFICATION TECHNIQUES 44.1 TYPE OF OUTAGE INDEX . 44.1.1 Universal Outage Index . 44.1.2 Service-based Outage Index 54.1.3 Decision on the Type of Outage Index 55. INTERRELA
12、TIONSHIPS OF SERVICES AND ARCHITECTURES. 55.1 DEFINITION OF SERVICE GROUP. 55.2 DEFINITION OF ARCHITECTURE CONCEPT. 55.2.1 Technologies and Platforms 55.3 SERVICE GROUPS AND ARCHITECTURES 55.4 INTERRELATIONSHIPS OF VOICEBAND SERVICES IN THE PSTN 65.4.1 Major Components of the PSTN . 65.4.2 A LOGICAL
13、 VIEW OF USER ACCESS TO PSTN VOICEBAND SERVICES . 66. SERVICES 76.1 PARTIAL LIST OF CANDIDATE SERVICES 77. ARCHITECTURES 87.1 WIRELINE. 87.2 WIRELESS. 87.3 PCS NETWORK BASIC ARCHITECTURE. 97.4 VOICEBAND TELEPHONY VIA CABLE TV 97.4.1 Background 97.4.2 Architectures 107.4.2.1 Cable Television Network
14、Evolution 107.4.2.2 New Wireline Access Networks. 107.4.3 Failure Modes, Effects, and Mitigation 117.4.3.1 Digital Switch. 117.4.3.2 Headend 117.4.3.3 Access Network Failure Modes. 117.4.3.4 Power 117.4.3.5 Hybrid Fiber/Coax Technology Failure Modes. 117.4.3.6 Fiber/Cable Cuts 127.4.4 Cable TV Netwo
15、rk Interconnections . 127.4.4.1 Description and Diagram. 12ii7.5 VOICEBAND TELEPHONY VIA SATELLITE. 137.5.1 Background 137.5.2 Services. 147.5.3 Architectures 147.5.4 Failure Modes, Effects, and Mitigation 167.5.4.1 Satellite Failure Modes 167.5.4.2 Earth Terminal Failure Modes . 167.5.4.3 Propagati
16、on Outages 177.5.4.4 Controller and Switching Center Failures . 177.5.5 PSTN Interconnection . 177.5.5.1 Critical Interconnections . 198. CUSTOMER-ORIENTED CLASSIFICATION AND QUANTIFICATION OF SERVICE OUTAGES 208.1 DEFINITION OF CUSTOMER . 208.2 DEFINITION OF EVENT TIMES . 218.2.1 Service Outage His
17、tory 218.3 SERVICE OUTAGE CLASSIFICATION 228.3.1 (U, D, E) Triples and Their Use. 238.3.1.1 (U, D, E) Definition 238.3.1.2 Example 1: Local Switch Failures 258.3.1.3 Example 2: Loss of Dial-Tone . 268.3.1.4 Example 3: Continual Data Collection. 269. SUGGESTIONS TO GENERAL INDUSTRY .2810. RECOMMENDAT
18、IONS TO STANDARDS ORGANIZATIONS. 2810.1 RECOMMENDATIONS FOR COMMITTEE T1. 2810.2 RECOMMENDATIONS FOR FUTURE T1A1.2 WORK 2811. SUMMARY. 2912. BIBLIOGRAPHY. 3013. DEFINITIONS 3114. ABBREVIATIONS AND ACRONYMS . 33APPENDIX A. AN OUTAGE INDEX FOR WIRELINE INDUSTRY SEGMENTS PROVIDING FIXEDVOICEBAND TELEPH
19、ONY SERVICE . 35A.1 INTRODUCTION. 35A.2 DATA ITEMS . 35A.2.1 Data Items for Dedicated Outages. 35A.2.2 Data Items for Diversified Outages . 36A.3 OUTAGE INDEX. 36A.3.1 Outage Index for Isolation from IntraLATA Intraoffice Service. 37A.3.2 Outage Index for Isolation from IntraLATA Interoffice Service
20、. 37A.3.3 Outage Index for Isolation from InterLATA Interoffice Service . 37A.3.4 Outage Index for Blocked Call Attempts. 38A.3.5 Outage Index for 911 Service 38A.4 COMMON TECHNIQUES 38A.4.1 Duration Weight. 38A.4.2 Magnitude Weight 39A.4.3 Time Factor 41A.4.4 Normalization. 41A.5 OUTAGE INDEX WORKS
21、HEETS 41iiiAPPENDIX B. AN OUTAGE INDEX FOR THE MOBILE WIRELESS INDUSTRY SEGMENT. 46B.1 INTRODUCTION. 46B.2 DATA ITEMS . 46B.3 OUTAGE INDEX. 46B.3.1 Index For Wireless Mobile Customers Blocked From Initial Registration . 47B.3.2 Index For Wireless Mobile Registered Customers Whose Call Attempts Are B
22、locked 47B.4 COMMON TECHNIQUES 48B.4.1 Duration Weight. 48B.4.2 Magnitude Weight 49B.4.3 Normalization. 50B.5 OUTAGE INDEX WORKSHEET 51APPENDIX C. OUTAGE INDEX FOR THE CABLE TV INDUSTRY SEGMENT . 53C.1 INTRODUCTION. 53C.2 DATA ITEMS . 53C.2.1 Data Items for Dedicated Outages. 53C.2.2 Data Items for
23、Diversified Outages . 54C.3 OUTAGE INDEX. 54C.3.1 Outage Index for Isolation from IntraLATA Intraoffice Service. 54C.3.2 Outage Index for Isolation from IntraLATA Interoffice Service. 55C.3.3 Outage Index for Isolation from InterLATA Interoffice Service . 55C.3.4 Outage Index for Blocked Call Attemp
24、ts. 55C.3.5 Outage Index for 911 Service 56C.4 COMMON TECHNIQUES 56C.4.1 Duration Weight. 56C.4.2 Magnitude Weight 57C.4.3 Time Factor 59C.4.4 Normalization. 59C.5 OUTAGE INDEX WORKSHEETS 59APPENDIX D. OUTAGE INDEX FOR THE MOBILE SATELLITE INDUSTRY SEGMENT 64D.1 INTRODUCTION. 64D.2 DATA ITEMS . 64D.
25、3 OUTAGE INDEX. 64D.3.1 Index for Satellite Mobile Customers Blocked from Registration 65D.3.2 Index for Satellite Mobile Registered Customers Whose Call Attempts are Blocked 65D.4 COMMON TECHNIQUES 65D.4.1 Duration Weight. 65D.4.2 Magnitude Weight 66D.4.3 Normalization. 68D.5 OUTAGE INDEX WORKSHEET
26、 68INDEX . 7110. Executive SummaryThis Technical Report supplements the Committee T1 Technical Report No. 24 (TR No. 24) on NetworkSurvivability Performance, which addresses the need for a common understanding and for techniques assessingnetwork survivability. This report resolves some of the issues
27、 and questions left for further study, as well asambiguities in TR No. 24 on the definitions of thresholds and on per-service definitions of unservability. TR No. 24emphasizes the classification of network failures (i.e., identifying whether or not a service outage has occurred) andaddresses the qua
28、ntification of failure events, and techniques to measure the severity of the failure. This report alsoprovides improved measures of failures with respect to service outage severity. Classification of the architecturesand services of industry segments other than the wireline (i.e., wireless, cable TV
29、, and satellite) is provided, andmethods are given in the corresponding appendixes to calculate outage index values for voiceband telephony serviceoutages.1. Purpose, Scope, Application, and Outline1.1 Purpose As a result of concerns from the telecommunications community, this report has beendevelop
30、ed to further address the survivability of telecommunications networks, including the services provided.This Technical Report supplements TR No. 24 on Network Survivability Performance 1. In particular, it increasesthe practicality of the methods in TR No. 24 and provides outage index methodologies
31、for the wireline (withoutFCC-reportable threshold criteria), wireless, cable TV, and satellite industry segments.1.2 Scope This report focuses on analyses related to network survivability performance. It does that withrespect to an end-users viewpoint of using voiceband services provided by a networ
32、k via a distribution technology(i.e., the means by which the services are provided). The end-users viewpoint is aligned with the Service layeridentified in Section 7.1 of TR No. 24. This report deals only with the Service layer.1.3 Application The intended audience of this report includes providers
33、of telecommunications networksand services, as well as suppliers of telecommunications equipment (see Section 3.1 of TR No. 24 for details).Network-provider personnel including designers, planners, traffic engineers, and individuals in charge ofoperations, administration, maintenance, and management
34、 can use this report to quantify and enhance thesurvivability of their networks. Telecommunications equipment suppliers can use this report to guide the designand building of equipment to improve network survivability. This report could assist regulators in understandinghow service providers may int
35、ernally monitor and evaluate the network service performance of their industrysegments. Each segment of the industry can use the corresponding appendix of this document to calculate theapplicable outage index methodology.1.4 Outline Section 2 provides information on other U.S. and international stan
36、dards bodies, forums andcommittees involved in work related to network survivability performance. Section 3 is an introduction for thisSupplement and the reason for its creation. Section 4 describes the functional application of this document.Section 5 relates services and architectures, and referen
37、ces where service outage index calculations are defined foreach industry segment. Section 6 lists and describes the services addressed in this report. Section 7 describesvarious network architectures covered by the outage index calculation methodologies of this report.Section 8 (similar to Section 4
38、 of TR No. 24) describes a framework for quantifying service outages. The basic unitis the event. An event coincides with a failure of hardware or software elements in a network. In each event, one ormore services may be affected. This report provides an appendix for each segment of the telecommunic
39、ationsindustry (wireline, wireless, cable TV, and satellite). Each industry segment-specific appendix describes (i) the dataneeded to characterize an outage of the voiceband telephony service offered by the corresponding networkarchitecture, and (ii) a technique combining that data into a value (an
40、outage index) reflecting the impact of aservice outage.Section 9 provides suggestions to the general industry on how to apply the information in this report for outages thatimpact voiceband telephony services. Section 10 makes recommendations to Committee T1 and Working GroupTechnical Report No. 24A
41、2T1A1.2 regarding refinement of the methodologies and future enhancements of the outage analysis. Section 11gives a brief summary of this report.For consistency, Appendix A provides the methodology for wireline service outage calculations based on that ofTechnical Report No. 42 (TR No. 42) on Enhanc
42、ed Analysis of FCC-Reportable Service Outages 2 withoutFCC-reportable threshold criteria. Appendixes B, C, and D provide extensions of this methodology to the wireless,cable TV, and satellite industry segments respectively. For ease of use, each appendix was written as a standalonedocument.2. Relate
43、d Work2.1 Committee T1 Standards Work In addition to T1A1, the following four T1 technical subcommitteesare involved in work related to network survivability performance: T1E1, T1M1, T1S1, and T1X1. T1E1 is considering environmental standards. These standards also impact network survivabilityperform
44、ance. T1M1 Working Group 2 (SONET OA the interconnected networks may be accessnetworks, or other interconnection networks.Industry Segments: Interexchange Carriers (ICs) and LECs.5.4.2 A Logical View of User Access to PSTN Voiceband Services The following table summarizes therelationships between in
45、dustry segments and PSTN voiceband services, and also gives the appropriate reference forcalculating outage index values.Technical Report No. 24A7Table 2. A Logical View of User Access to PSTN Voiceband ServicesIndustry Segments LEC / IC CellularCAP SatellitePCSCATVAccess TypeWired / Wireless Wirele
46、ssDistribution Media TWP / Coax / Fiber / Radio RadioAnalog Digital Analog DigitalAMPSPOTS CDMAGSMISDN TDMAN/AMPSTransmissionPublic Switched Telephone Network (PSTN)911 Intraoffice Interoffice (IntraLATA or InterLATA)Voiceband ServicesCPE Terminal ProtocolOutage Index Ref. TR No. 42 App. BApp. A App
47、. DApp. BApp. CNetwork TypeAMPS - Advanced Mobile Phone Service LATA - Local Access Transport AreaCAP - Competitive Access Provider LEC - Local Exchange CarrierCATV - Cable Television N/AMPS - Narrowband AMPSCDMA - Code Division Multiple Access PCS - Personal Communications ServicesCPE - Customer Pr
48、emises Equipment POTS - Plain Old Telephone ServiceGSM - Global System for Mobiles TDMA - Time Division Multiple AccessIC - Interexchange Carrier TWP - Twisted PairISDN - Integrated Services Digital Network6. ServicesThis section lists and describes the services addressed by this Supplement to TR No
49、. 24. The selection anddelineation of services should be guided by users perspectives. For example, differentiating between “IntraLATAIntraoffice calling” service and “IntraLATA Interoffice calling” service may not be useful, while differentiating the911 Service from other services may be useful. Based on requests from the NRC, the list should include servicesfrom wireless, cable TV, and satellite service providers.6.1 Partial List of Candidate Services This section contains a list of services for analysis. Furtherinvestigation may indicate the need to m
