Cross-layer routing for peer database querying over mobile ad hoc networks

The widespread of mobile ad hoc networking calls for a careful design of network functions in order to meet the application requirements and economize on the limited resources. In this paper we address the problem of distributing query messages among peers in mobile ad hoc networks. We assume that peers are organized in classes. Each peer possesses a local database and can answer queries posed by other peers. Each peer can also pose queries to all the peers belonging to a certain class or classes. Contrary to traditional p2p lookup queries, we are interested in collecting answers from as many peers as possible. We propose a query routing protocol, called CL-QF, which is based on a novel cross-layer design. The purpose of this design is to incorporate application layer specifics (e.g., class information) into the network layer in order to reduce transmissions therefore economize on resources. CL-QF coexists with traditional routing. This synergy minimizes the complexity and signaling of CL-QF while the network is able to seamlessly provide legacy unicast communication. CL-QF manages a reduction of up to ∼78% compared to non-cross-layer approaches, such as probabilistic forwarding, without compromising the ability to effectively collect replies.