在有基礎架構之車載網路中利用Chord機制改善P2P效能的研究

• Main Authors: 許孜銚, Hsu, Tzu Yao
• Language: 中文
• Published: 國立政治大學
• Subjects: 點對點; 車載網路; p2p; vehicular network; chord
• Online Access: http://thesis.lib.nccu.edu.tw/cgi-bin/cdrfb3/gsweb.cgi?o=dstdcdr&i=sid=%22G0095753026%22.

在vehicular network中應用Peer to peer (p2p)是目前尚在研究的一項領域。不同於一般wired network的環境，vehicular network環境中變動性相當高，且車輛移動速度快，車輛間無法長時間維持連線，所以若要在vehicular network上分享檔案資源，會遭遇到許多問題，像是如何在網路上有效率地搜尋所需要的檔案、相距甚遠的車輛如何分享彼此的資源、在有限的頻寬中如何發揮最大的分享效益，皆是十分重要的課題。本研究提出Urban Multi Layered Chord (UML-Chord)架構，在市區環境的vehicular network中，引入infrastructure-based的架構，以解決ad-hoc環境中只能靠車輛機會相遇時交換訊息，僅能做範圍內搜尋的缺點。另外我們使用multi-layered chord來管理網路上分享的檔案資源，此種結構化的p2p架構可以有比較好的搜尋效率。在檔案傳輸上，我們加入交通號誌的狀況後，讓車輛間連線預估時間(connection lifetime)更加精確，得以選出最適合的節點下載檔案，增加檔案的傳輸效率，提昇整體p2p應用的效能。 === Peer-to-peer (p2p) applications on vehicular network is a significant research topic today .Vehicular network is different from traditional wired network environment in some characteristics. Topology is very dynamic and vehicles driving in high speed, the connection between vehicles can’t maintain in a long time in vehicular network. If we want to share file resources on vehicular network, there are some problems to confronted, like the efficiency of query operations, sharing files with distance vehicles and fully utilizing the limited bandwidth. Our paper proposes an Urban Multi-layered Chord (UML-Chord) method in urban Vehicular network. Introducing infrastructure based architecture to deal with the problem that cars can exchange their files only when they meet each other in ad-hoc mode. In addition, we use multi layered chord to manage file resources which should be shared on Internet. This kind of structured p2p architecture has better efficiency in searching files. For file transfer part, we take stop light into account. We modify connection lifetime, let it be used in choosing appropriated download peers, enhancing the efficiency of p2p application.