A Contact-History Based Routing for Publish-Subscribe Scheme in Hierarchical Opportunistic Networks

Opportunistic networks is aimed to provide a solution for communication in disrupt tolerate networks, which has attracted lots of researches. However, for reasons such as finite buffer size and energy of nodes in opportunistic networks, the further improvement of network performance is limited. Therefore, we set powerful cluster nodes in the network to form hierarchical opportunistic networks. In this paper, a publish/subscribe scheme in hierarchical opportunistic networks is put forward. The object of publish/subscribe scheme is to realize the sharing of resources between nodes. In our scheme, nodes disseminate their data requests with a TTL value to limit their flooding and after receiving the subscribed data items, an ACK will be flooded to delete the useless data packets in the network. To choose appropriate relays for data packets, a utility function to estimate the relay ability of nodes is designed, what’s more, cluster nodes are brought in as relay nodes too. Simulations are given to demonstrate the performance improvement of our scheme.