1、 ETSI TR 102 445 V1.1.1 (2006-10)Technical Report Emergency Communications (EMTEL);Overview of Emergency CommunicationsNetwork Resilience and PreparednessETSI ETSI TR 102 445 V1.1.1 (2006-10) 2 Reference DTR/EMTEL-00005 Keywords diversity, emergency ETSI 650 Route des Lucioles F-06921 Sophia Antipol
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6、extend to reproduction in all media. European Telecommunications Standards Institute 2006. All rights reserved. DECTTM, PLUGTESTSTM and UMTSTM are Trade Marks of ETSI registered for the benefit of its Members. TIPHONTMand the TIPHON logo are Trade Marks currently being registered by ETSI for the ben
7、efit of its Members. 3GPPTM is a Trade Mark of ETSI registered for the benefit of its Members and of the 3GPP Organizational Partners. ETSI ETSI TR 102 445 V1.1.1 (2006-10) 3 Contents Intellectual Property Rights4 Foreword.4 Introduction 4 1 Scope 5 2 References 5 3 Definitions and abbreviations.5 3
8、.1 Definitions5 3.2 Abbreviations .5 4 Resilience concepts 6 4.1 Overview 6 4.2 Component level resilience concept.6 4.3 Multiple component operation concept 6 4.4 Circuit diversity and separacy concepts in line transmission systems6 4.5 Diverse routing concepts 7 4.6 Fault-tolerant concepts .7 4.7
9、Disaster Recovery (DR) concepts 7 4.8 Service diversity.7 5 Emergency communications network resilience7 5.1 Overview 7 5.2 Local exchange/mobile switch to PSAP.8 5.3 PSAP 8 5.4 ECC 8 5.5 PSAP/ECC integration/separation9 5.5.1 Integrated PSAP and ECC 9 5.5.2 Separated PSAP and ECC.9 5.6 ECC to emerg
10、ency service personnel.9 5.6.1 Mobile radio systems 9 5.6.1.1 Redundancy in the Radio Access Network (RAN) .10 5.6.1.2 Resilience in the Radio Access Network (RAN) 10 5.6.1.3 Resilience in the transmission network.11 5.6.1.4 Resilience in the switching network11 5.6.1.5 Resilience outside the networ
11、k infrastructure .11 5.6.2 Private Networks 11 5.7 Planning/enhancing resilience 12 6 Emergency communications network preparedness 12 6.1 Overview 12 6.2 General Requirements 12 6.3 Communication from individuals to authorities/organizations 13 6.4 Communication between authorities/organizations13
12、6.4.1 Commercial cellular networks 13 6.4.2 Conditions for implementation will be subject to national and regional technical and commercial agreements between Emergency Services Organizations, network operators and other relevant parties.(Future) digital mobile broadband technology 13 6.5 Communicat
13、ion from authorities/organizations to individuals, groups or the general public 13 6.6 Communication amongst individuals during emergencies.14 Annex A: Basic architecture15 History 16 ETSI ETSI TR 102 445 V1.1.1 (2006-10) 4 Intellectual Property Rights IPRs essential or potentially essential to the
14、present document may have been declared to ETSI. The information pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found in ETSI SR 000 314: “Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI i
15、n respect of ETSI standards“, which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web server (http:/webapp.etsi.org/IPR/home.asp). Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee can be given as
16、to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web server) which are, or may be, or may become, essential to the present document. Foreword This Technical Report (TR) has been produced by ETSI Special Committee Emergency Communications (EMTEL). Introduct
17、ion The concept of Emergency Telecommunications (EMTEL) addresses a broad spectrum of aspects related to the provisioning of telecommunications services in emergency situations. In emergency situations, efficient and effective communications is critical. The enabling telecommunications technology ne
18、eds to perform in a robust and reliable manner, providing the requisite functionality to guaranteed service levels. Network resilience and preparedness are critical. The present document provides an overview of several key technical concepts that can be employed to enhance network resilience. The do
19、cument then considers the application of these concepts within the different systems that typically integrate to facilitate emergency communications between the public and emergency personnel. The present document concludes by considering network preparedness and the requirement for specialized syst
20、ems and capabilities in exceptional situations. ETSI ETSI TR 102 445 V1.1.1 (2006-10) 5 1 Scope The present document presents resilience concepts and considers their application within technical systems enabling emergency communications and also considers network preparedness and requirements for sp
21、ecialized systems and capabilities. 2 References For the purposes of this Technical Report (TR), the following references apply: NOTE: While any hyperlinks included in this clause were valid at the time of publication ETSI cannot guarantee their long term validity. 1 ETSI SR 002 180: “Requirements f
22、or communication of citizens with authorities/organizations in case of distress (emergency call handling)“. 2 ETSI TS 102 181: “Requirements for communication between authorities/organizations during emergencies“. 3 ETSI TS 102 182: “Requirements for communications from authorities/organizations to
23、individuals, groups or the general public during emergencies“. 4 National Infrastructure Security Co-Ordination Centre (UK): “Telecommunications Resilience“. NOTE: Available at: http:/www.niscc.gov.uk/niscc/bestPractice-en.html?yr=2004Available at: http:/www.unisdr.org/ resilience: concept associate
24、d with resisting to the loss of capacity of a failure or foreseen overload, optimizing the availability and quality of service of telecommunications systems and support resources enabling a system to return to a previous normal condition 3.2 Abbreviations For the purposes of the present document, th
25、e following abbreviations apply: DMO Direct Mode Operation DR Disaster Recovery ECC Emergency Control Centre PSAP Public Safety Answering Point PSRN Public Safety Radio Network RAN Radio Access Network ETSI ETSI TR 102 445 V1.1.1 (2006-10) 6 4 Resilience concepts 4.1 Overview Resilience is a concept
26、 associated with optimizing the availability and quality of service of telecommunications systems and support resources. The objectives are to maximize Mean Time Between Failure and to minimize Mean Time To Repair. Resilience applies at all levels in the system hierarchy: at component level and at s
27、ystem level, and within switching systems, transmission systems and end devices. A short overview of key concepts is provided in the following clauses. 4.2 Component level resilience concept Component level resilience is the concept of incorporating features into the design of an individual componen
28、t of equipment to enhance its overall availability. Such features include: Incorporation of multiple redundant modules within the component such as power supplies, processor units and data storage modules. Localized storage of information within the component to enable continued operation in the eve
29、nt of failure of higher-level information sources. 4.3 Multiple component operation concept Multiple Component Operation is the concept of deploying several components to fulfil a particular aspect of system functionality. Components are typically arranged in parallel. Multiple Component Operation c
30、an be arranged in several modes: Redundant Mode: In the event of failure of the active component, operation is switched to the standby component. The switchover operation can be range from manual intervention to fully automatic. Active Parallel Mode: In the event of failure operation continues but w
31、ith reduced capacity. The different modes have differing advantages and disadvantages. Regarding Redundant Mode, design of the application and design of the clustering is simpler and there should be little performance loss in the event of a failure. However the total cost of the system is likely to
32、be higher. Regarding Active Parallel Mode, the opposite arguments will apply: design is more complex and there is performance degradation in the event of a failure, but the total cost of the system will likely be lower in comparison to Redundant Mode. 4.4 Circuit diversity and separacy concepts in l
33、ine transmission systems Diversity is the concept of ensuring that specified circuits are not routed over the same transmission circuits. However there may be some common physical network sites and/or equipment within the circuit routings. Separacy is a more reliable means of ensuring that specified
34、 circuits are not routed over the same cables, equipment or transmission systems and also that there are no common physical sites within the circuit routings. Normally, separated routes will even enter a building through separated ports using different service facilities (power etc.). They will only
35、 physically combine at the circuit terminal equipment. It should be noted that separacy guarantees diversity, but diversity does not guarantee separacy. ETSI ETSI TR 102 445 V1.1.1 (2006-10) 7 In theory a single incident affecting one particular circuit should not affect transmission capacity in cir
36、cuits that are diverse or separate. However, the avoidance of a single point of failure can only be guaranteed in fully separated circuits. 4.5 Diverse routing concepts Diverse routing concepts relate to the ability to use, select or switch between different circuits to avoid congestion or network f
37、ailure. Diverse routing capability is built upon the provision of transmission diversity and separacy. Routing and transmission devices are capable of detecting a reduction in performance on a particular circuit and reroute traffic based on specific rules. 4.6 Fault-tolerant concepts Fault tolerant
38、systems are devices that are designed and built to correctly operate even in the presence of a software error or failed components. The term is most commonly used to describe computer systems designed to lose little or no time due to issues, either in the hardware or the software running on it. 4.7
39、Disaster Recovery (DR) concepts Disaster Recovery (DR) is a coordinated activity to enable the recovery of telecom/IT/business systems due to a disruption. DR can be achieved by restoring telecom/IT/business operations at an alternate location, recovering telecom/IT/business operations using alterna
40、te equipment, and/or performing some or all of the affected business processes using manual methods. 4.8 Service diversity Service diversity is a concept whereby if a particular communications service fails, information (or a subset of information) can be transferred by an alternate communications s
41、ervice. Examples include: If a Public TV service fails, Public Radio systems could still broadcast Emergency Messages. If a Commercial Cellular Telephone system fails, Commercial Paging systems could still be used for Emergency communications. 5 Emergency communications network resilience 5.1 Overvi
42、ew The telecommunications networks used to enable emergency communications span a very broad group of systems, technologies and interfaces. For the purposes of the present document, the arrangement illustrated in SR 002 180 1 is considered. This is reproduced in annex A. Consideration of the applica
43、tion of the key resilience concepts to emergency communications is provided in the following clauses. Avoidance of Single Points of Failure is a key concept throughout. Transparency on the end-to-end routing of emergency calls is also critical. ETSI ETSI TR 102 445 V1.1.1 (2006-10) 8 5.2 Local excha
44、nge/mobile switch to PSAP The set-up of the call to a Public Safety Answering Point (PSAP) may take a number of routes originating from a fixed or mobile network or possibly transiting a point of interconnect. In each case an emergency call is given a higher priority than other traffic. The initial
45、stage (customer to PSAP) achieves this based upon analysis of the call destination. Various resilience techniques are applicable to emergency calls. Typically emergency calls will have access to additional routes (although not exclusive). This occurs throughout the network, including access to multi
46、ple switches that support emergency communications services. It should be noted that the PSAPs themselves are connected to more than one switch. In times of overload, Restrictive Network Management controls can be applied. Normal calls can be restricted to use a smaller number of circuits than usual
47、ly available. However, priority calls are made exempt from such restrictions, effectively meaning that certain circuits are protected and made available for priority traffic only in times of overload. In times of normal load, all circuits are available and work normally. Hence this technique may be
48、carried out on newer “Next Generation Networks“ but may also be configured on current Circuit Switched networks. Telecom operators use a number of other techniques to protect the network from the impact of fault conditions and during periods of high traffic. Often public networks can be subject to a
49、 large number of short duration very high traffic periods as a result of “phone-ins“ to TV and Radio. The impact of these events are controlled by the use of call-gapping to protect the network. This will also restrict emergency calls if a user cannot access a dial tone. 5.3 PSAP PSAPs typically house “contact centre“ technology to enable the efficient and effective handling of emergency calls. In this environment, fault tolerant systems are appropriate to ensure very-high system availability. The concept of Multiple Component Operation can also be applie
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