Broadcasting is a commonly used operation in mobile ad hoc networks (MANETs), where a source node diffuses a message to all other nodes in the network. Flooding, a process in which each node retransmits every uniquely received packet exactly once is the simplest mechanism used for broadcasting in MANETs. Despite its simplicity, it can result in high redundant retransmission, contention and collision, a phenomenon collectively referred to as the broadcast storm problem. Counter-based broadcast scheme has been proposed to mitigate this inherent problem and it relies on counter threshold value for rebroadcast decision. Thus, the selection of an appropriate counter threshold-value is crucial to the performance of the scheme. However, previous studies have focused on determining an optimal counter threshold-value using a network setting with very low traffic load. In this paper, we investigate the effects of the counter threshold value on the performance of counterbased scheme in terms of number of retransmitting nodes, reachability and collision rate, using Ns-2 simulation under varying network density and traffic load. Simulation results have revealed that an optimal counter threshold for sparse networks is smaller than that of dense networks. Thus, while most previous studies have often used a single fixed value for the counter, this paper argues that the optimal counter threshold is network density dependent.
Broadcasting, Flooding, Broadcast Storm Problem, Counter-based, Collision rate, Reachability