Summary: | 碩士 === 國立中正大學 === 資訊工程研究所 === 92 === In this thesis, we propose a Scalable, self-organizing, self-addressing, and Location-Aware Peer-to-Peer (P2P) system on mobile ad hoc networks (MANET), referred as SLAP. Many P2P systems have been proposed in wired networks, such as Gnutella, CAN, Chord and Pastry. However, they are not directly applicable to MANET due to node mobility. Mobility posts many challenges on P2P file sharing systems, especially on search accuracy. In the literature, several proposed solutions for P2P file sharing system on MANET use static and flat address, thus need to search files based on flooding. However, the flooding approach causes extremely high traffic overhead as network grows. In this thesis, our SLAP solves the high traffic overhead problem by building an application layer overlay network. Three important issues are discussed in SLAP, namely dynamical addressing, routing, and sharing mechanisms. The dynamical addressing mechanism self-organizes nodes into a tree-based overlay network for scalability. Through the novel addressing scheme, it enables nodes to be roughly aware of its physical location in the underlying network when they have joined SLAP. Next, the routing mechanism in SLAP is based on the longest-prefix matching method to avoid massive control overheads of flooding. Besides, a routing cache is used to reduce length of routing paths and load of high level nodes. On final issue, the sharing mechanism proposed in this thesis is based on distributed hash function, which is more systemic and efficient than the flooding approach. Therefore, SLAP achieves high throughput rate and low control overhead for large MANET with hundreds of nodes. Simulation and analysis are performed to evaluate the efficiency and scalability of the proposed system. Our numerical results show that SLAP outperforms the flooding approach significantly in searching overhead and system throughput. We have also implemented the proposed system on PDAs with IEEE 802.11 network interfaces.
|