Modified Token Based Congestion Control Scheme for Opportunistic Networks

Sa？etak To address congestion issues in Opportunistic Networks (OppNets) a modified token-based congestion control with adaptive forwarding mechanism is proposed. The mechanism allows the network nodes holding a valid token to inject message into the network or other neighboring node. At the point of congestion, the algorithm has the potential to redirect the traffic from more congested node to congestion free node for the purpose of effective resource utilization and fairness in the network. Tokens are evenly distributed throughout the network. Using opportunistic network environment (ONE) simulator we illustrate the performance of modified token-based congestion control algorithm, which results in reduction for messages, and network transit time due to congestion across all the scenarios considered. At different queue sizes of (QS-10, QS-20, QS-30 and QS-40), modified token based congestion control algorithm has 13.91%, 10.71%, 5.46%, and 4.22% respectively reduction in dropped messages. In addition, at greatest connected component values of 50%, 60%, 70% and 80%, modified token-based congestion control has 8.34%, 2.19%, 4.61%, and 7.63% respectively decrease in network transit time. These results are substantial because they indicate a reduction in both network storage as well as time