EnTER: an encounter based trowbox deployment strategy for enhancing network reliability in post-disaster scenarios over DTN

Delay-tolerant network (DTN) has been employed as a viable option for exchanging situational information during post-disaster communication. In contrast to stable network, network reliability in DTN depends on the contact opportunities among the nodes (both mobile and static). Higher degree of contact opportunity implies improved message delivery with reduced delivery latency, which results in enhanced network reliability. In order to improve the degree of contact opportunity among the nodes the deployment of static relay nodes (Throwboxes) has been widely adopted. In order to deploy Throwboxes effectively, prior knowledge regarding network parameters like scale of the network, network topology and mobility pattern of nodes etc. is essential. However, availability of such parameters in post disaster scenarios becomes challenging. Therefore, in this work, we propose an encounter based Throwbox deployment strategy EnTER. The proposed strategy attempts to formulate an empirical relationship between the degree of contact opportunity and extent of network reliability in DTN. The extent of network reliability is measured in terms of Knowledge Sharing Ratio and Average Delivery Latency. This relationship helps in formulating a suitable strategy for deploying Throwboxes in a post-disaster scenario. Extensive simulation by implementing a realistic post-disaster scenario reveals that our proposed Throwbox deployment strategy outperforms one of the state-of-the-art Throwbox deployment strategies in terms of network reliability.