Abstract: In this paper analysis a DTNs backup network for infrastructure intensive areas or a low-cost communication structure in severe environments. This paper focus on distributed peer-to-peer file search in a delay tolerant network (DTN) formed by mobile devices, the holders of which exhibit certain social network properties. However, due to sparse node distribution and continuous node mobility, DTNs are featured by frequent network partition and intermittent connections. DTN Packet forwarding is often realized in a store-carry-forward manner in DTN routing algorithms, which means that a message is carried by current holder until meeting another forwarder. Furthermore, due to the distributed network structure, it is almost impossible to maintain global file distribution information in DTNs. In this existing we design three components in Contact and Content model: community creation, neighbor table construction and update and content and contact based file search. Common-interest communities benefit file searching from two aspects: (1) it increases the probability that a node finds its interested files in its own community since common-interest nodes tend to meet more frequently and (2) it can enable a request to learn the destination community directly. The neighbor table provides organized information regarding how to find the requested file efficiently and the propose system implement a advanced techniques that can further enhance file searching efficiency, thought at additional costs.

Keywords: DTN, store-carry forward, packet forwarding.