Master of Science (MS)
Delay Tolerant Networks are wireless networks that have sporadic network connectivity, thus rendering the existence of instantaneous end-to-end paths from a source to a destination difficult or impossible. Hence, in such networks, message delivery relies heavily on the store-and-forward paradigm to route messages. However, limited knowledge of the contact times between the nodes poses a big challenge to effective forwarding of messages. In this thesis, we discuss several aspects of routing in DTNs and present one algorithm and three variants for addressing the routing problem in DTNs: (i) the Look-ahead Protocol, in which the forwarding decision at each node to its immediate or one-hop neighbor is based on the position of the packet / message in the queue of the neighboring node(ii) Backpressure based lookahead, where a lookahead factor is introduced with the basic backpressure equation. This factor takes into account the difference of queue lengths from the neighbors, (iii) a two-step lookahead protocol, where the forwarding decision is sometimes based on the instantaneous one-hop neighbors of the neighboring node. We also present simulation results of these protocols and compare these results to the existing standard routing protocols for DTNs. In all the algorithms, we look to optimize the amount of network bandwidth used by looking one step ahead before making a forwarding decision. By considering the queue in the neighboring nodes, the amount of network resources consumed decreases. The protocols that we propose may come with a slightly higher hop-count per packet than most protocols, but we have tried to maintain a comparable delivery ratio with the existing standard protocols
Document Availability at the Time of Submission
Release the entire work immediately for access worldwide.
Rotti, Priyanka, "Opportunistic lookahead routing procedure for delay tolerant networks" (2012). LSU Master's Theses. 3153.