never die network towards disaster-resistant … · invited paper never die network towards...

Invited Paper

NEVER DIE NETWORK TOWARDS DISASTER-RESISTANT INFORMATION

COMMUNICATION SYSTEMS Norio Shiratori1, 2, Noriki Uchida3, Yoshitaka Shibata4, and Satoru Izumi2

1Graduate School of Global Information and Telecommunication Studies, Waseda University, Bldg. No. 29-7, 1-3-10 Nishi-Waseda, Shinjuku-ku Tokyo 169-0051 Japan, [email protected]

2 Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira Aobaku, Sendai, Miyagi 980-8577 Japan, [email protected]

3 Graduate School of Human and Social Study, Saitama Institute of Technology, 1690 Fusaiji, Fukaya, Saitama 369-0293, Japan, [email protected]

4 Faculty of Software and Information science, Iwate Prefectural University 152-52 Sugo, Takizawa, Iwate 020-0193 Japan, [email protected]

Received Date: September 19, 2012

Abstract The Great East Japan Earthquake on March 11, 2011 that left 20,000 people dead or missing have brought strong emotional impact of earthquake and tsunami throughout the whole world. Recently, Japanese government reported that an M9 Nankai Trough earthquake may result in as high as 323,000 deaths and devastate wide area of the coastline in Japan. In the March earthquake, the damages such as death, missing persons, and collapse became serious because of the disruption in information communication systems such as telephone network, local area network, cellular phone, etc. Therefore, disaster-resistant information communication systems have become one of the major challenges for the researchers and engineers. In this paper, we discuss our proposed “Never Die Network” which is one of the disaster-resistant information communication systems and site examples based on our painful experiences of the Great East Japan Earthquake that had a great impact not only on ways of our lives but also on the future of science and technology.

Keywords: Disaster-resistant Information Communication System, Never Die Network, The Great East Japan Earthquake.

Introduction In science and technology of the 21st century, how to face global environmental change such as global warming and natural disasters has come into question. Regarding natural disasters, the Great East Japan Earthquake on March 11, 2011 that left 20,000 people dead or missing have brought strong emotional impact of earthquake and tsunami throughout the whole world. In addition, recently, Japanese government reported that an M9 Nankai Trough earthquake would trigger big tsunami that may result in as high as 323,000 deaths and devastate wide area of the coastline in Japan [1]. Figures 1, 2, and 3 show the serious damages caused by the Great East Japan Earthquake and Tsunami. The damages such as death, missing, and collapse became serious because of the disruption in information communication systems such as telephone network, local area network, cellular phone, etc. as shown in Table 3. Therefore, disaster-resistant information communication systems became one of the major challenges for the researchers and engineers. In this paper, we discuss “Never Die Network” which is one of the disaster-resistant information communication systems related to the natural disasters such as big earthquakes and tsunami, and provide examples based on our painful experiences of the Great East Japan Earthquake.

ASEAN Engineering Journal, Vol 2 No 1, ISSN 2229-127X, e-ISSN 2586-9159 p.1

Before going into the detail discussion of Never Die Network, we briefly introduce an overview of the great earthquakes and tsunamis in Japan and the world and their histories. In Japan and outside Japan, we have had very great earthquake and great earthquake as is respectively shown in Table 1 and Table 2. As shown in these tables, over the years, many people died or went missing by the earthquakes and tsunamis. To decrease the number of dead and missing, it is strongly expected to develop disaster-resistant information communication systems worldwide. Authors had painful experiences of Great East Japan Earthquake on March 11, 2011. Based on the knowledge of our experiences, we have been promoting research activities towards realization of Never Die Network.

This paper is organized as follows. In Section 2, we explain the history of disaster-resistant information communication systems. Especially, we introduce Never Die Network which is one of the disaster-resistant information communication systems, its characteristics and comparison with related research works. In Section 3, we discuss serious problems caused by the Great East Japan Earthquake. Based on our painful experiences, we point out problems which became obstacles for rescue activities and problems of ICT caused by limited network conditions. Required information for disaster response based on our knowledge gained from our experiences of past disasters is summarized in Section 4. In Section 5, two examples of Never Die Network are given. One is an example of system behavior of Never Die Network, and another one is an example of system construction of Never Die Network. Conclusion is presented in Section 6.

Figure 1. Prefectural road recovered by removing tsunami rubble in Miyagi Prefecture

2011/05/05


Figure 2. Boat swept by tsunami about 2 km away from the sea in Miyagi Prefecture

Figure 3. Damaged gas station by tsunami located about 1 km away from coast in Miyagi Prefecture


Table 1. Very Great Earthquakes and the Effects Name Year Magnitude Earthquake

Intensity Tsunami Number

Of Dead And

Missing Cascadia earthquake

1700 8.7-9.2 - yes -

Arica earthquake

1868 8.5-9.0 - yes 25,000

Kamchatka earthquakes

1952 9.0 - yes 2,336

Great Chilean Earthquake

1960 9.5 6 yes 2,231-6,000

Great Alaskan Earthquake

1964 9.2 - yes 131

Indian Ocean Earthquake

2004 9.1 - yes 227,898

Chile earthquake

2010 8.8 - yes 802

Great East Japan Earthquake

2011 9.0 7 yes 18,723

Table 2. Great Earthquakes and the Effects Name Year Magnitude Earthquake

Intensity Tsunami Number Of

Dead And Missing

Yaeyama Great Earthquake

1771 7.4-8.0 4 yes 12,000

Lisbon earthquake

1755 8.5-9.0 - yes 55,000-62,000

Ansei-Tokai earthquake

1854 8.4 7 yes 2,000-3,000

Mexico City earthquake

1985 8.0 - yes 9,500

Kikaijima earthquake

1911 8.0 6 yes 12

Kanto Great Disaster

1923 7.9 6 no 105,385

Sanriku earthquake

1933 8.1-8.4 5 yes 3,064

Nankaido earthquake

1946 8.0 6 yes 1,333

Hokkaido Tohooki Earthquake

1994 8.2 6 yes 11

Tokachioki 2003 8.0 6 yes 2


Earthquake Kuril Islands earthquake

2006 8.3 2 yes 0

Peru earthquake

2007 8.0 - yes 514

Great Sichuan Earthquake

2008 7.9 - no 61,197

Samoa earthquake

2009 8.1 - yes 189

History of Disaster-resistant Information Communication Systems Historically, there is no existence of disaster information network which is dedicated to general purpose for disasters except for the special closed and physical networks for such as military or police uses. On the other hand, there are mainly two types of packet based networks which consider the network failure on lines, network nodes. One is Network Fault Tolerance System [2] and the other is Resilient Overlay network [3]. As such, we summarize research on disaster-resistant information communication systems including our proposed Never Die Network as follows.

(1) Network Tolerance System [2]In Network Tolerance System, the network failure caused by physical component

failure of LAN or interconnected LAN environment, such as cable, network interface card, switch and router are considered. In order to recover from network component failure, at least, a pair of network sets including, cable and router is installed in parallel. If one of the network sets fails, the failure is detected by the network management protocol such as SNMP and the other network is selected to cover the failure. Thus, Network Tolerance System deals with hardware based recovery by dual network component set.

(2) Resilient Overlay Network [3]On the other hand, Resilient Overlay network is an application-layer overlay on top of

the existing Internet routing substrate. The Resilient Overlay network nodes monitor the functioning and quality of the Internet paths among themselves, and use this information to decide whether to route packets directly over the Internet or through other Resilient Overlay network nodes, optimizing application-specific routing metrics even in case some of the network nodes become non-functional.

As common characteristics of those networks, both networks consider only stable wired configuration, not wireless or adhoc networks. Both do not include autonomous network reconfiguration ability through multiple layers, multiple links and multiple channel environments. Furthermore, there is no guarantee of connection between any network nodes. Therefore, those are not always used as disaster information network.

(3) Never Die Network [4,5]<Original Concept>

The original concept of Never Die Network (NDN) was proposed by the authors [4, 5] in 2003. The originality of NDN is an autonomous network control method (communication method and protocol) and management method to assist the NDN system for continuing to work even in case of emergency such as disaster. This is achieved by the use of technologies to collect and analyze network information (communication connectivity, traffic congestion, etc.) for expressing network status in real time. Thus,


NDN aspires for provision of uninterrupted communication even in case of emergency such as disaster. The authors’ group has succeeded in standardizing one of such technologies in IETF as a basic technology [6]. <Concept of NDN>

We have been investigating concepts, their models, and applications based on the original concept of NDN [7,8,9,10] and revised it in a step-by-step manner. The concept of NDN is summarized as the following 5 points. 1) Even if a part of the system is damaged due to external factors, such as a disaster, NDNwill continue to work without halting the whole system by autonomously finding analternative route or a node, and establishing communication link. Thus, NDN aspires forprovision of uninterrupted communication.2) In order to improve the “never die” characteristics, NDN tries to control divisions andmultiplexing of the available bandwidth.3) Moreover, by introducing a layered structure such as wired and wireless, NDN aspiresfor provision of uninterrupted communication services even if the degree of systemdamages spreads.4) Comparing to Network Tolerance System and Resilient Overlay network mentionedabove (1) and (2), the concept of NDN includes not only hardware, but also software,communication methods and its protocols such as wired, wireless, satellite, balloon,mobile, etc. Therefore, the concept of NDN includes the concepts of both NetworkTolerance System and Resilient Overlay network.5) Performance characteristics such as connectivity, throughput, etc. of NDN are as shownin Figure 4.

Figure 4. Performance characteristics (connectivity, throughput, etc.) of Never Die Network

(4) Research activities in Japan after March 11, 2011

The Great East Japan Earthquake had a great impact not only on ways of our lives butalso future of science and technology. Just after the earthquake, government, companies, and universities in Japan started various types of research and developments for disaster reconstruction. For example, Japanese government launched the Reconstruction Agency.


Regarding information and communication system, IPSJ solicited and published journal special issues on information and communication technologies for disaster reconstruction [20]. IEICE is also preparing their journals for special issues on disaster [21]. Furthermore, government agencies, companies and universities started research projects. For example, National Institute of Information and Communication Technology (NICT) started research projects on disaster information network with groups of domestic communication enterprises such as NTT, NTT docomo, KDDI, NEC, NHK etc. in collaboration with Tohoku University and supported by the government [22]. Kyushu University started research with national disaster information system particularly for the disaster by heavy rain in Kyushu in collaboration with the Ministry of Land, Infrastructure, Transport and Tourism [23]. Hokkaido University started wireless ballooned communication networks in collaboration with Softbank for serious disaster cases when the communication infrastructure on ground area is completely damaged [24].

Regarding Never Die Network, Iwate Prefectural University is developing a new one which is organized by multilayered and multilinked architecture with heterogeneous wireless networks including the small mobile satellite IP networks, millimeter-wave wide-band networks and wireless ballooned ad hoc networks in addition to the conventional Wi-Fi and Wi-Max. All of those network components are operated and controlled by Software Defined Network framework (SDN) to perform self-power supplied function, self-cognitive and diagonal function for network quality and failure detection function, dynamical reconstruction function from the failure to always work even though the worst case where all of the network components on the ground are completely damaged and destroyed by huge disaster more than the scale of Eastern Japan Great Earthquake. Currently, the project team, led by Prof. Yoshitaka Shibata, is constructing a prototype and evaluating functional and performance of a new NDN which covers the several areas in the Sanriku coast seriously damaged by Eastern Japan Great Earthquake.

Serious Problems Caused by the Great East Japan Earthquake

Problems which Became Obstacles to Rescue Activities The Great East Japan Earthquake on March 11, 2011 caused severe and tremendous damages over the wide area of Northern Japan. A massive 9.0 earthquake destroyed many buildings and equipment. Moreover, devastating waves of tsunami swept over cities and coastal residential areas. The earthquake and tsunami left 15,868 dead, 2,848 missing, and 6,109 injured persons [11]. In major earthquakes recorded in the world history, it was the fourth largest earthquake next to Great Chile Earthquake in 1960 (M9.5), Great Alaskan Earthquake in 1964 (M9.2), and Indian Ocean Earthquake and Tsunami in 2004 (M9.1) [12]. However, this tragedy gave a great shock to the world.


Figure 5. Lack of food in a convenience store in Iwate Prefecture

Problems of ICT caused by Limited Network Conditions Besides the causalities, the earthquake caused many secondary disasters such as blackouts, lack of food, and lack of fuel in the wide area of Japan as shown in Figure 5. Especially, disconnection of communication networks also brought severe damages over the nation. Disconnection of mobile phones and the Internet created great confusions in today’s highly developed IT society. It also caused the delay of various rescue and support activities. Shibata et al. reported about the problems from communication network disconnections by the earthquake and their network reactivating efforts on the coast side of Iwate Prefecture in their papers [13][14].

Their papers reported various problems that emerged during the activities after the occurrence of the disaster. First of all, the breakdown of exportation systems caused scarcity of fuel and food in the stores. The lack of fuel and food had spread in a vast area of Japan. It led to the delay of rescue and support activities. Most of food such as rice and breads disappeared from the cities, and many people could not go to coastal areas because of the lack of gas. Secondly, lack of information such as damages and evacuation affected rescue activities. Since the damages were spread over a vast area, it was very hard to obtain local disaster information around them.

The followings are additional major problems during their activities: (1) Fuel for cars was difficult to get.(2) Electricity and battery for information network systems was damaged(3) Network devices and servers were damaged(4) Wired networks were disconnected(5) Cellular phone systems were damaged and congested(6) Government Disaster Radio System had broken down(7) TV could not be watched


(8) In many evacuation shelters, handwriting papers were used to obtain disasterinformation and to search for missing persons.

The papers also reported damages of various communication systems. Table 3 is the summary of network conditions in Iwate Prefecture.

Table 3. Network Conditions of Various Communication Systems System Conditions Details

Radio ○ Small area service such as local FM radio was useful for evacuators.

TV × It did not work because of wide area’s blackout.

Fixed phone × Devices were damaged and blacked out Cellular phone (audio) △ Highly congested Internet (Cellular phone) △ Highly congested Iwate Information Highway (Government’s Information Network System)

× Broke down network and devices.

LAN in City Hall × Broke down network and devices. Disaster Government Radio System

△ Unable to hear inside the house or car.

Amateur Radio ○ Worked but only a few devices and licensed users

Wireless LAN ○ Worked but electricity was needed Satellite system (internet) ○ Worked

Especially, cellular phones and Internets could not work because of severe congestion and damages of the devices. It made great effects on various aspects. According to Ministry of Internal Affairs and Communication, just after the earthquake, numbers of telecommunication over cellular phones had increased about 10 times compared with its usual numbers. Furthermore, the maximum limitation of audio communication became up to 95% [15]. Then, they pointed out that only wireless network and satellite system are useful for their network recovery activities. Moreover, they also indicated that the network connectivity was very important for the early stage of the disaster because the early stage of disaster information mainly consists of life related information such as rescue and evacuation, and the information is preferred to be text contents such as web service. Therefore, they mentioned that in the early stage of the disaster, disaster-resistant information communication systems should be focused on the connectivity more than throughput or delay of data transmission, and then they introduced these concepts to the extensional designs of NDN.

Required Information for Disaster Response In designing NDN, Shibata et al. discussed from the studies of the previous large natural disasters [16] [17] that the required information changes with time, before and after the disaster. The required information through the time transition is shown in Table 4. This information and knowledge were gained from experiences of past disasters, especially from The Great East Japan Earthquake on March 11, 2011.

ASEAN Engineering Journal, Vol 2 No 1, ISSN 2229--127X, e-ISSN 2586-9159 p.9

Table 4. Required Information through the Time Subject Required Information /

time t1 t2 tx t3 t4 t5 t6

Victim Disaster Prevention △ ○

Evacuation ○ ◎

Safety ◎ ◎ ○ △

Stricken Area ◎ ○

Traffic ○ ◎ ◎

Relief Supplies ◎ ○

Public Service ○ ◎

Lifeline ○ ◎

Local Government ○ ◎

Relatives Volunteer

Safety ◎ ◎ ○

Stricken Area ◎ ○ △

Relief Supplies ○ ◎

Condition Activities Period

t1 Normal --- ---

t2 Indication of Disaster

Indication, rumor etc 2 weeks before – Disaster

tx Occurrence of Disaster

--- During Disaster

t3 Just after Disaster

Rescue, evacuation, safety of life

Disaster – 2 days

t4 Calm down from Disaster

Relief materials, safety of life

3days – 2 weeks

t5 Restoration from Disaster

Restore lifeline, residences, and so on

3 weeks - several months

t6 Revival --- ---

According to Table 4, the forecast and evacuation information are required during the term t1; but evacuation information is not so much important at this stage. However, if there are some kinds of indications such as news or rumor about disaster during t2, evacuation and disaster prevention becomes more important than usual. Then, when disaster occurs, very significant activities relating to human lives such as rescue, evacuation, and safety status information come to be required. Since the information is


much related to human lives during the term of t3, NDN should be focused on the network connectivity more than throughput or latency. Also, text contents are mainly used for the disaster evacuation, resident safety and disaster status information.

In later phases, delay or throughput become important while the connectivity is less focused after recovery stages.

Examples of Never Die Network Based on our painful experiences of past disasters as is discussed in Section 4, we give two examples of Never Die Network (NDN). One is an example of system behavior of NDN, and another one is an example of system construction of NDN.

NDN is a robust network method proposed by Shiratori et al. [4,5], and it is aimed at ensuring effective network control method for disaster-resistant information communication system. The papers [4,5] mentions that NDN is defined as a robust network which will be unaffected by any changes in environment such as a sudden degradation or fluctuation of quality of network capability. To realize NDN, they proposed the network control method by infra-depend mode and autonomous mode. Once disaster is happened, network switches to autonomous mode. In autonomous mode, network condition is grasped, and a new administration node is selected for the route reconstruction. Shibata et al. extended their proposal and discussed NDN more preciously by comparing with current wired and wireless networks [8].

In case of their proposed NDN, data connection is robustly kept as shown in Figure 6. In the figure, wired network is easy to be influenced by disaster. The connectivity of wireless network or CWN (Cognitive Wireless Network) is stronger than wired network, but their connectivity may be disrupted by the scale of strong disaster. On the other hand, NDN keeps the data connection even if transmission quality comes to be lower as shown in Figure 7. This figure shows the data connectivity of various networks through elapsed time. NDN needs to guarantee minimal data connections such as Figure 7. After the occurrence of severe disaster at tx, network conditions rapidly degrades. However, with NDN it is possible to provide minimal data transmission unlike other traditional information communication systems.

Figure 6. System failure by scale of disaster

NDN


Figure 7. System failure through elapsed time

An Example of System Behavior of NDN There are some approaches trying to realize NDN today. First of all, Shibata et al. proposed the optimal network control methods of Cognitive Wireless Network (CWN) and satellite system [18][19]. They proposed the new cognition cycle, which consists of three stages; the observation stage, the decision stage, and the acting stage as shown in Figure 8. Each stage is continuously cycled in order to perform link or route configuration.

Figure 8. Proposed cognition cycle

At observation stage, user and wireless environments are observed by the change of required information that is mentioned in Section 4 and by the observation values such throughput or PER (Packet Error Rate). Then, these parameters are used for the calculation of link and route selection at decision stage. In this stage, they proposed to extend AHP (Analytic Hierarchy Process) method for the link selection in order to consider the user policies, and extend AODV (Ad hoc On-Demand Distance Vector) routing with Min-Max AHP value for the route selection in order to use the extended AHP results. At last, these computational results are used for the network reconstruction.

They also discussed the evaluation from the simulation results as shown in Figure 9, and the effectiveness of their proposed method made the network to become robust and to recover quickly. As the results of the simulation, it is considered that the proposal methodｓ realize the requirements of NDN as shown in Figure 6 and 7. That is because the result shows the robust connectivity and quick recovery in comparison with other networks.

NDN


Figure 9. Simulation results

An Example of System Construction of NDN In order to realize the never die property, we designed an NDN consisting of three-layered architecture by using wired and wireless network [9]. Figure 10 shows its overview of the system construction. The first layer is constructed by the Wi-Fi full-mesh public wireless network in accordance with IEEE 802.11s standard. The second layer is a core network which connects among the central areas of the distributed branches. This layer is constructed based on the 4.9 GHz long-distance wireless network. However, when the two branches are close, they will be connected by the Wi-Fi full-mesh network. By introducing this architecture, we can keep the connectivity to the Internet in the disaster, and ensure the never die property of the information communication systems.

Moreover, Never Die Messaging System as in Figure 11 performs a bulk delivery of the important information to a variety of media to protect the safety of people in the initial phase after the disaster. This system uses public information such as J-ALART warning system, public information commons, information from Japan Meteorological Agency, etc., as the input to the system. Then, this system outputs the information to users by using multiple media. After the Great East Japan Earthquake, accurate information could not be delivered to the residents due to the damage of the public disaster-prevention announcement system. Therefore, this system aims to deliver the serious lifesaving information tenaciously, via several devices which have been already retained by the residents.

Next, to realize fault-tolerant file systems at the time of disaster, the single point of failure should be eliminated. Therefore, we need the disaster-resistant file system that cannot be affected totally by the damages even in case that a part of file system in the file server is lost. We investigate Never Die File System as shown in Figure 12 as an infrastructure of the platform to achieve centralized management of information of safety and aid delivery, etc. We install storages in buildings of several branch offices based on the distributed storage architecture for disaster recovery. If perchance one of the branch offices is affected by the disaster, the rest of the system provides function of the total file system.

NDN


Figure 10. An example of Never Die Network with three-hierarchical network structure

Figure 11. An example of Never Die Messaging System


Figure 12. An example of Never Die File System

Conclusion In this paper, we have discussed Never Die Network which is one of the disaster-resistant information communication systems. The Great East Japan Earthquake brought into account strong impacts of natural disasters all over the world, and many problems are still remaining in the North and East Japan. The information communication systems became one of the significant issues to reduce the damage caused by natural disasters. According to authors’ painful experiences of the earthquake, uninterrupted communication was very important no matter how worse the throughput or delay in the network is. Hence, achieving disaster-resistant information communication systems such as Never Die Network has become one of the major challenges for the researchers and engineers.

As the future works, it is expected to promote research for fundamental technologies towards realization of Never Die Network to reduce the damages caused by the disaster such as big earthquake and tsunami.

Acknowledgement We have generous support from the staff of the Student Support Room in Iwate Prefectural University, Dr. Akihiro Yuze in Shizuoka Prefectural University, Dr. Kaoru Sugita in Fukuoka Institute of Technology, Mr. Yuji Ohashi in GFJ, Mr. Toshihiro Tamura in NetBridge, Saitama Institute of Technology, Japan Science and Technology Agency (JST), KDDI, and Coretec for our disaster activities. The authors are grateful to Dr. Tsutomu Inaba, NTT East-Miyagi, for his numerous discussions on the design of system construction of NDN.


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