魏宏宇臺灣大學:電機工程學研究所劉哲良Liu, Che-LiangChe-LiangLiu2010-07-012018-07-062010-07-012018-07-062009U0001-1408200912005000http://ntur.lib.ntu.edu.tw//handle/246246/188126Efficient content distribution is one of the emerging applications in vehicular networks. To provide scalable content distribution in vehicular networks, Chord peer-to-peer overlay could be applied. Most P2P protocols, including Chord, are designed for wired-line network, and might perform poorly in mobile networks. Mobile Chord (MChord) is proposed to enhance the P2P performance over vehicular ad hoc network (VANET). In addition, cross-layer design to improve MChord performance in VANET is also investigated. Extensive NS-2 simulations with vehicular mobility traces are conducted to evaluate the P2P overlay performance in VANET. Mobile Chord and its cross-layer design outperforms the original Chord in various aspects, including application layer forwarding steps, query response ratio, correct query response ratio, and application delay.Abstract iist of Figures iiiist of Tables v Introduction 1 RelatedWork 4.1 Characteristics of P2P Networks . . . . . . . . . . . . . . . . . . . . . . 4.2 Chord and Application-Layer DHT . . . . . . . . . . . . . . . . . . . . . 5.3 P2P Protocol Enhancement . . . . . . . . . . . . . . . . . . . . . . . . . 7.4 Cross-layer design for P2P overlay . . . . . . . . . . . . . . . . . . . . . 8 Mobile Chord Protocol Design 10.1 Aggressive Table Update . . . . . . . . . . . . . . . . . . . . . . . . . . 11.2 Overlay Table Broadcasting . . . . . . . . . . . . . . . . . . . . . . . . . 11.3 Greedy forwarding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.4 Passive bootstrapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Cross-layer enhancement for Mobile Chord 16.1 Cross-layer Knowledge Harvesting . . . . . . . . . . . . . . . . . . . . . 16.2 Knowledge Piggyback In Overlay Signaling . . . . . . . . . . . . . . . . 18 Performance evaluation 20.1 Mobility Model Characteristics . . . . . . . . . . . . . . . . . . . . . . . 25.2 Static Grid Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28.3 Bootstrapping Performance . . . . . . . . . . . . . . . . . . . . . . . . . 31.4 Traffic Reduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32.5 Vehicular Network P2P Performance . . . . . . . . . . . . . . . . . . . 34.6 Overlay Table Broadcasting Interval . . . . . . . . . . . . . . . . . . . . 43.7 Comparative Performance in Different Mobility Schemes . . . . . . . . . 44.8 Overlay Table Size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 Conclusion 49ibliography 501152761 bytesapplication/pdfen-US同儕網路車用無線網路peer to peer networkvehicular ad hoc networkthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/188126/1/ntu-98-R96921030-1.pdf