Modified Token Based Congestion Control Scheme for Opportunistic Networks

Abstract

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 a 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 the opportunistic network environment (ONE) simulator, we illustrate the performance of a modified token-based congestion control algorithm, which results in reduction of dropped 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 the greatest connected component values of 50%, 60%, 70% and 80%, the 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 and time.