Ferry Replacement Protocols In Sparse Manet Message Ferrying Systems

The Message Ferrying (MF) scheme has been proposed as a strategy for providing connectivity in sparse partitioned ad hoc networks. A set of nodes called ferries are responsible for carrying messages for all nodes in the networks. A ferry periodically moves around the deployed area along a pre-determined route and relays messages between mobile nodes which otherwise cannot communicate with each other directly. The MF scheme relies on the ferry to provide connectivity and is vulnerable to a single point of failure. Also, mobile nodes might take turns to be a ferry since they normally have limited resources. Therefore, ferry replacement is important for robustness in the MF deployment. In this paper, we propose two ferry replacement protocols. The ferry designates its successor in the designation scheme while nodes collaborate and elect one node among themselves as the ferry replacement in the distributed election approach. We evaluate the performance of these two replacement protocols through comprehensive simulation.