Institutionen för datavetenskap Department of Computer and Information Science Final thesis Implementation of a manycast protocol for intermittently connected mobile ad hoc networks in disaster areas by Ekhiotz Jon Vergara Alonso LIU-IDA/LITH-IDA/ERASMUS-A—10/01—SE 2010-06-26 !"#$%&"#'()*#"+,-(".,. !"#$%&"#'()*#"+,-(".,. /01234)35)!"#$%&"#'6)/7,8,# 234)35)!"#$%&"#' !"#$%&"#'()*#"+,-(".,. /#(.".*."0#,#)1%-)23.3+,.,#($3& 4536,#(3-7,., !"#$%"%&'(')*&+*,+(+"(&-.(/'+#0*'*.*$+,*0+ )&'%0")''%&'$-+.*&&%.'%1+"*2)$%+(1+3*.+ &%'4*05/+)&+1)/(/'%0+(0%(/ (6 753)*'8+9*&+:%0;(0(+<$*&/* !/89/:;<!/=>9/:;<4?;@A8@9;BCD<DCB@4 EDCD9DF9EF >3#2G,23-,H)A"$3,G);(&G*#2 4536"#3.0-H):-I)@"6"#)J32K69=,L-3#" På svenska Detta dokument hålls tillgängligt på Internet – eller dess framtida ersättare – under en längre tid från publiceringsdatum under förutsättning att inga extra- ordinära omständigheter uppstår. 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For additional information about the Linköping University Electronic Press and its procedures for publication and for assurance of document integrity, please refer to its WWW home page: http://www.ep.liu.se/ © [Författarens för- och efternamn] Abstract Nowadays, the use of mobile phones and other wireless devices has become an in- dispensable part of daily life. However, the focus of wireless communication is on infrastructure-based networks, making them prone to service outage if for any reason the infrastructure is overloaded or there is no network coverage. This is the case in a dis- aster area, where the infrastructure that supports the communication may be destroyed or could become useless. Different approaches to complement the exchange of information in these scenarios are emerging as research results. This thesis concerns Random-Walk Gossip (RWG), which is a protocol to disseminate information in disaster areas. RWG is a many- cast protocol for intermittently connected mobile ad hoc networks. The more people can communicate, the more chances of success there are. Therefore, it is useful to investigate the possibility of implementing such protocols on commodity devices. Since Symbian is currently the most widespread mobile phone operating system, this master’s thesis presents the implementation of the protocol in that platform. The protocol is also implemented in Linux and Mac OS X in order to provide heterogeneity. Finally, some aspects of the performance of the protocol in different devices are analyzed, studying the CPU load, memory consumption, radio range, energy consumption and response time of different devices using the protocol. The studies show that the use of the RWG protocol in both laptops and handheld devices is viable. Acknowledgements I would firstly like to thank Dr. Simin Nadjm-Tehrani, Dr. Urko Zurutuza and Mikael Asplund for their guidance, interest, expertise and kindness. My gratitude also goes to all the members of the Real-time Systems Laboratory (RTSLAB). It has been a pleasure to be part of the group during this period. Finally, I would also like to thank my family, girlfriend and friends for their invaluable support. Contents 1 Introduction 3 1.1 Background . 3 1.2 Motivation . 4 1.3 Goals ...................................... 4 1.4 Intended audience . 5 1.5 Structure .................................... 5 1.6 Related work . 5 2 Random-Walk Gossip protocol 7 2.1 Characteristics . 7 2.2 Type of packets . 8 2.3 Header . 9 2.4 Event-based . 10 2.5 Partition tolerance mechanisms . 11 2.6 Energy efficiency . 12 3 Symbian Operating System 14 3.1 Symbian evolution . 14 3.1.1 Characteristics . 15 3.1.2 Symbian Platform . 16 3.2 Developing for Symbian . 17 3.2.1 Symbian C++ . 17 3.2.2 Python . 19 3.2.3 Open C/C++ (P.I.P.S.) . 20 3.2.4 The Qt framework . 22 3.2.5 MoSync . 23 4 Implementation 24 4.1 RWG implementation . 24 4.1.1 Language Choice . 24 4.1.2 User space vs. Kernel space . 25 4.1.3 Wireless communication . 25 4.1.4 Architecture design . 26 1 CONTENTS 2 4.1.5 Data Storage . 27 4.1.6 Task Storage . 28 4.1.7 Network . 28 4.1.8 Core and Dispatcher . 29 4.1.9 Modifications to the original algorithm . 31 4.2 RWGAPI.................................... 32 4.3 User application . 33 4.4 Heterogeneity . 35 5 Evaluation 37 5.1 Functionality tests . 38 5.1.1 Uninterrupted connectivity . 39 5.1.2 Multihop . 41 5.1.3 Partition tolerance . 41 5.2 Device-dependent tests . 45 5.2.1 CPU load . 45 5.2.2 Memory use . 47 5.2.3 Time measurements . 49 5.2.4 Power consumption . 53 6 Conclusions 58 6.1 Implementation-specific observations . 58 6.2 Protocol-specific discussion . 59 6.3 Summary and future work . 60 A Implementation tools 62 B RWG API messages 63 C Devices 65 D Radio range 67 E Network trace 69 F Multihop network trace 72 G Hop field discussion 77 H Instructions to run the protocol and the application 79 Bibliography 82 Chapter 1 Introduction This report describes the results of a Master’s Thesis project (30 ECTS) as partial fullfil- ment of a degree in Telecommunications Engineering and was performed at Department of Computer and Information Science at Link¨oping University, as a visiting student from Mondragon Unibertsitatea. The document begins by describing the background and motivation for the work in this section. Advances in technology have created new forms of communication, where one of the most common is the wireless communication. Nowadays, the use of mobile phones has become an indispensable part of daily life. For example, in countries like USA or Ghana, there are more mobile subscribers than telephone main lines [1]. A mobile phone can be all you need in order to communicate in a certain moment, with the advantage of being in any place at the communication time. This need of exchanging information is even more crucial in areas where disasters have taken place, due to tornadoes, earthquakes, terrorism acts or wars. In such a scenario, a simple text message could help to find someone or to inform rescue teams. 1.1 Background Wireless communication has grown significantly in the last years. It allows communica- tion among many different devices without any mobility restriction. Different technolo- gies have been developed in order to exchange information, such as cellular networks (GSM, UMTS), cordless telephony (DECT), wireless networks (WLAN, WiMAX) or short-range wireless communication (IrDA, Bluetooth). Generally, the focus of wireless communication is on infrastructure-based networks, making them prone to service outage if for any reason the infrastructure is not available or there is no network coverage. This is the case of a disaster area, where the infrastructure that supports the com- munication could become useless. When a disaster takes place, the infrastructure can be seriously damaged or overloaded. As a consequence, several special telecommunication equipments are used (e.g. satellite phones). However, as these equipments are scarce and expensive, other approaches to complement the exchange of information are appearing [22], in order to establish communication and increase the chance of success. These kind 3 CHAPTER 1. INTRODUCTION 4 of scenarios offer challenges which are similar to the main research topics of the following networks: Mobile Ad hoc Networks (MANET): these are networks that do not rely on any infrastructure. Each device in the network can be auto-configured in order to create links among other devices [6]. MANET are ad hoc networks, where each node can move freely changing and establishing interconnections with other nodes [8]. This network can be quickly created when the need exists. Delay Tolerant Networks (DTN): these networks, also referred to Disruption-Tolerant Networks, are networks that are able to support communication with intermittent connectivity. The message reliability is achieved using techniques like store-and- forward. Hence, the nodes have to store the data before transmitting it. DTN are used is in space networks [26], where the nodes have to deal with the asynchronous communication and delayed exchanges of information. Other applications include sensor networks or mobile devices. 1.2 Motivation A partition-tolerant manycast algorithm called Random-Walk Gossip (RWG) was pre- sented and evaluated [2] in order to disseminate information in disaster areas.