Forming structured P2P overlays over disjoint MANET clusters.

Generally, WiFi is used to provide connectivity to mobile device users at public places like airports, railway stations, etc. Mobile devices can utilize WiFi as underlying substrate to run structured Peer-to-Peer (P2P) overlay applications for content sharing. The density of mobile users at these places is unpredictable, and often many users may not get WiFi facility. This is due to the fact that at any instance, WiFi access points can provide services to a limited number of users. Another alternative is to form a Mobile Ad hoc Network (MANET) of these mobile devices for running structured P2P overlay applications. However, due to non-uniform distribution of users different disjoint clusters of MANET may be formed. This results in formation of different disjoint Distributed Hash Tables (DHTs) at the application level, leading to inefficient lookup performance. In this paper, we suggest two possible approaches for connecting these disjoint DHTs. In the first approach, existing WiFi infrastructure can be utilized to act as a bridge between the disjoint partitions; whereas in the second approach, strategically deployed fixed relay nodes can be used for merging the partitions. The first approach is more challenging, as it requires dynamic switching between the two modes (infrastructure/ad hoc) of wireless network interface cards of mobile devices. The second approach is naive, but may act as good proof of concept to justify connecting disjoint DHTs.