Trusted spanning trees for Delay Tolerant Mobile Ad Hoc Networks

摘要

Delay tolerant networks (DTNs) are an extension of mobile ad-hoc networks (MANETs). Global knowledge in DTNs cannot be obtained or guaranteed due to their dynamicity, decentralized nature and non-permanent structure. Managing such networks optimally is very difficult, if not impossible. Trust management in such networks receives much attention recently due to their potential application. One solution for managing information within DTNs lies in constructing and maintaining spanning forests. DA-GRS is a local computation based model for the description of decentralized algorithms designed for dynamically distributed environments like delay-tolerant MANETs (DTMs). DA-GRS proposes a framework for constructing and maintaining a spanning forest in such an environment. This work introduces the notion of trust into DA-GRS resulting in T-DA-GRS algorithm. The goal of the proposed algorithms is to construct and maintain robust trusted spanning tree where less trustable nodes are leaves. Three cost functions are suggested as means to assess the robustness of trusted spanning trees. T-DA-GRS is also further improved by incorporating greedy algorithm to become T-GDA-GRS. These algorithms were tested with four different networks generated by a DTM simulator known as Madhoc. Efficiency of these algorithms is compared with optimal values.