Dynamic, ad-hoc source routing with connection-aware link-state exchange and differentiation

We propose an enhancement to DSR, called DSR with Connection-Aware Link-state Exchange aNd DiffERentiation (DSR-CALENDER). Specifically, to effectively collect and disseminate neighbor link states to nodes which may potentially use them, we devise a neighbor link-state information exchange mechanism: once a connection has been established, the neighbor link-state information is exchanged among nodes along the route from the source to the destination. As the information of the neighbor lists is piggybacked in data packets, the nodes on the source route are able to learn the partial topology around the neighborhood of the connection. In this manner, DSR-CALENDER balances the gain obtained from additional neighbor link states and the overhead incurred to distribute them. In the case that link failure occurs, an alternate route can be more effectively located in the route cache of the source or the intermediate nodes, and the number of times the route discovery phase is invoked can be reduced. To improve the quality of route caches, we investigate all possible sources from which a node may learn of its link states, and associate each of the sources with a different level of fidelity. In the case that a new/alternate route has to be computed, the level of fidelity is figured into the link cost so as to locate a route that likely exists. The simulation results show that with limited overhead incurred in neighbor list dissemination, DSR-CALENDER outperforms DSR with either path or link caches in terms of packet delivery ratio and route discovery overhead.