Personal Networks An Architecture for Self-Organized Personal Wireless Communications Proefschrift ter verkrijging van de graad van doctor aan de Technische Universiteit Delft, op gezag van de Rector Magnificus Prof.dr.ir. J.T. Fokkema, voorzitter van het College voor Promoties, in het openbaar te verdedigen op dinsdag 17 juni 2008 om 10.00 uur door Martin Edvard JACOBSSON Magister i Datavetenskap van Link¨opings Universitet, Zweden geboren te Boo, Zweden. Dit proefschrift is goedgekeurd door de promotor: Prof.dr.ir. I.G.M.M. Niemegeers Samenstelling promotiecommissie: Rector Magnificus, Voorzitter Prof.dr.ir. I.G.M.M. Niemegeers, Technische Universiteit Delft, promotor Prof.dr.ir. S.M. Heemstra de Groot Technische Universiteit Delft Prof.dr.ir. L.P. Ligthart Technische Universiteit Delft Prof.dr.ir. H.J. Sips, Technische Universiteit Delft Prof.dr.ir. E.R. Fledderus, Technische Universiteit Eindhoven Prof.dr.ir. I. Moerman, Universiteit Gent Prof.dr. R. Prasad, Aalborg Universitet ISBN 978-90-9023196-9 Keywords: Wireless communication, Ad hoc networking, Self-organization This research was partially supported by the European Commission under the research projects IST NEXWAY, IST MAGNET, and IST MAGNET Beyond and the Dutch Ministry of Economic Affairs through the project PNP2008 under the Freeband Communication Impulse of the technology programme. Copyright c 2008 by M. Jacobsson All rights reserved. No part of the material protected by this copyright notice may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording or by any information storage and retrieval system, without written permission from the author. Printed in The Netherlands Acknowledgements This thesis describes work that I performed at Wireless and Mobile Com- munications group at Delft University of Technology under Prof. Ignas Nie- megeers. It was his thoughtful guidance that gave me the opportunity to understand the research process and the scientific community, first during my M.Sc. thesis work and then during my Ph.D. thesis work. His encourage- ments, enthusiasm, support, and insights have been invaluable. Further, I would like to thank the committee members for spending time and providing feedback to this thesis. Thanks also to all my colleagues with whom I have had many fruitful and/or joyful discussions. In relation to this thesis, I am especially grateful for the cooperation with Cheng Guo, Jinglong Zhou, Venkatesha Prasad, Anthony Lo, Novi Ineke CempakaWangi, Weidong Lu, and Ertan Onur. I am also grateful to Przemyslaw Pawelczak and Bao Linh Dang for for helping me out taking the photos for this thesis. In addition, there are also a couple of M.Sc. students who contributed to this work by doing their final projects with me. I would like to acknowledge them here: Yan Gao, Xiang Han, Cheng Guo (again), and Ting Liu. Thanks to IST MAGNET, MAGNET Beyond, Freeband PNP2008, IST NEXWAY, and IOP GenCom QoS for PN@Home, I had the privilege to work with many excellent researchers. They provided me with plenty of opportunities to discuss and enhance the concepts and ideas that lie behind this thesis. By getting to know you, I am sure that we will find ways to mutually enhance each other’s work also in the future! Finally, I want to thank my family. This is of course not only limited to my parents, my brother, and my wife, but also uncles, aunts, cousins, and all my Indonesian and Dutch in-laws. Special thanks to my brother-in-law for translating the summary and propositions to Dutch. Without my wife, I would never have become a PhD student in Delft! Tack, Terima Kasih, Bedankt, Thank You! Martin Jacobsson Delft To My Wife. Contents 1 Introduction 1 1.1 Past, Present, and Future Telecommunication . 1 1.2 PersonalNetworks .. ..... ..... ..... ..... .. 4 1.2.1 TravelingSaleswomanScenario . 6 1.2.2 CarefortheElderly .. ..... ..... ..... .. 8 1.3 Research Motivations, Targets, and Scope . 9 1.4 ResearchMethodology . 10 1.5 ThesisOverview.... ..... ..... ..... ..... .. 10 1.6 ContributionsofthisThesis . 11 2 RequirementsandRelatedWork 13 2.1 Requirements for Personal Networks . 13 2.1.1 Ubiquitousnetworking . 14 2.1.2 Respecting heterogeneous hardware constraints . 14 2.1.3 QoSandreliability . 15 2.1.4 Naming and service management . 16 2.1.5 Contextawareness . 17 2.1.6 Securityandtrust. 17 2.1.7 Privacy .......................... 18 2.1.8 Usability.......................... 18 2.1.9 Otherrequirements . 19 2.2 RelatedWork ........................... 20 2.2.1 Adhocnetworking . 20 2.2.2 WWRFBookofVisions . 21 2.2.3 Ubiquitous and pervasive computing and communication 23 2.2.4 AmbientNetworks . 24 2.2.5 IST PACWOMAN and SHAMAN . 25 2.2.6 Personal DistributedEnvironment. 26 2.2.7 MyNet........................... 27 2.2.8 P2P Universal Computing Consortium . 28 2.2.9 Morerelatedwork . 29 2.3 RelatedWorkRequirementAnalysis . 30 2.4 Summary ............................. 31 vii viii CONTENTS 3 The Personal Network Architecture 33 3.1 TheThreeLevelArchitectureView . 34 3.2 MainConceptsandTerminology. 35 3.2.1 Connectivityabstractionlevel . 35 3.2.2 Network abstraction level . 36 3.2.3 Applicationand serviceabstraction level . 37 3.2.4 Otherconcepts .... ..... ..... ..... ... 38 3.3 TheThreeAbstractionLevels . 38 3.3.1 Connectivityabstractionlevel . 38 3.3.2 Network abstraction level . 39 3.3.3 Applicationand serviceabstraction level . 41 3.3.4 Interactionbetweenthelevels . 43 3.4 PersonalizationofNodes . 43 3.5 ClusterOrganization . 45 3.6 PNOrganization .. ..... ..... ..... ..... ... 47 3.7 ForeignCommunication . 49 3.8 PNArchitectureDiscussion . 49 3.8.1 Why a network layer overlay? . 50 3.8.2 HowprotectedisaPN? . 50 3.8.3 HowusableisthePNSecurity? . 52 3.8.4 DoweneedtomanageourPNs? . 52 3.8.5 Whataboutthesocialdimension?. 53 3.8.6 Moreissues?. ..... ..... ..... ..... ... 55 3.9 Summary ............................. 55 4 Cluster Formation and Maintenance 57 4.1 Definition,Scope,andRequirements . 58 4.2 RelatedWork ........................... 60 4.3 ClusterFormation. 61 4.3.1 Multi-hopClusters . 63 4.3.2 Linklayerdevicediscovery . 64 4.3.3 Discovery of Node arrivals and departures . 65 4.3.4 MergingandsplittingofClusters . 66 4.3.5 Clustermemberlist. 66 4.4 PersonalNodeAuthentication . 67 4.4.1 Neighbor Node authentication . 67 4.4.2 Anonymity ........................ 68 4.5 Establishmentof SecureCommunication . 70 4.5.1 Secureunicastcommunication . 70 4.5.2 Trust Relationship-awareness at the connectivity level . 71 4.5.3 Secure broadcast communication . 72 4.6 ThePrototype........................... 73 4.6.1 Hardware platform . 73 4.6.2 Linux ........................... 74 CONTENTS ix 4.6.3 OLSRd .......................... 75 4.6.4 Implementation architecture . 75 4.6.5 Sendingintra-Clustertraffic . 77 4.6.6 Interfaceoutputqueue . 79 4.6.7 Receivingintra-Clustertraffic . 79 4.6.8 Lessonslearned . 79 4.7 Summary ............................. 80 5 Cluster-Wide Broadcasting 81 5.1 Cluster-WideBroadcasting Requirements . 82 5.2 RelatedWork ........................... 83 5.2.1 Counter-Based Broadcasting . 83 5.2.2 FloodingwithSelf-Pruning. 84 5.2.3 Scalable Broadcasting Algorithm . 84 5.2.4 AdHocBroadcastingProtocol. 85 5.2.5 Otherfloodingprotocols . 85 5.2.6 Realnetworksexperiments . 86 5.3 Prioritized FloodingwithSelf-Pruning . 87 5.3.1 Self-PruningAspects . 87 5.3.2 ThedesignofRAD ... ..... ..... ..... .. 88 5.3.3 Earlyretransmissions. 92 5.4 TheTestBedEnvironment. 96 5.4.1 The hardware and software platform . 96 5.4.2 Experimentsetup. 98 5.5 ExperimentalResults. 100 5.5.1 Optimizing the protocol parameters (phase one) . 101 5.5.2 Flooding protocol comparison (phase two) . 105 5.5.3 Measurementconclusions. 107 5.6 SimulationResults . .108 5.7 ThePrototype..... ..... ..... ..... ..... ..112 5.8 Summary .............................113 6 UnicastRoutinginClusters 115 6.1 RequirementsforRoutinginClusters . 116 6.2 RelatedWork ..... ..... ..... ..... ..... ..117 6.2.1 Routingprotocols. 117 6.2.2 Routingmetrics. .119 6.3 LinkQualityAssessment . 121 6.3.1 Hellopackets . ..... ..... ..... ..... ..122 6.3.2 Signalstrength . .123 6.3.3 Datapacketretranmissions . 125 6.3.4 Othermeasures . .126 6.3.5 Bi-directionalLQA . 127 6.3.6 Heterogeneousairinterfaces . 128 x CONTENTS 6.4 ExperimentalResults . 128 6.4.1 LQAexperiments. .129 6.4.2 LQAandpathselection . 131 6.4.3 LQA with rate adaptation . 134 6.4.4 LQA with and without data traffic . 135 6.5 RoutingProtocolsforClusters . 135 6.5.1 LQAupdating .... ..... ..... ..... ...135 6.5.2 Differentpacketsizes . 136 6.5.3 End-to-end quality of intra-Cluster paths . 138 6.6 ThePrototype.... ..... ..... ..... ..... ...139 6.6.1 Madwifidriver .... ..... ..... ..... ...139 6.6.2 Modificationstoppand. 140 6.6.3 Modifications to the routing daemon . 140 6.6.4 Lessonslearned . .141 6.7 Summary .............................141 7 PN Organization 143 7.1 Inter-ClusterTunnelingRequirements. 145 7.2 RelatedWork .... ..... ..... ..... ..... ...146 7.3 PNAddressing ... ..... ..... ..... ..... ...149 7.4 InfrastructureSupport . 150 7.4.1 PNAgent .........................150 7.4.2 EdgeRouters ..... ..... ..... ..... ...152 7.4.3 PN networking without infrastructure support . 154 7.5 Inter-ClusterTunneling. 155 7.5.1 Mobilityanddynamictunneling . 155 7.5.2 Always-up and on-demand tunneling . 157 7.5.3 Gateway Node coordination . 159 7.5.4 NATtraversal. .159 7.5.5 Tunnelingandsignalingsecurity. 160 7.6 Inter-ClusterRouting. 161 7.6.1 PNAgent-basedrouting . 162 7.6.2 Tunnelqualityassessment . 163 7.6.3 PN-widebroadcasting