Impact of Trust-based Security Association and Mobility on the Delay Metric in MANET

Trust models in the literature of MANETs commonly assume that packets have different security requirements. Before a node forwards a packet, if the recipient's trust level does not meet the packet's requirement level, then the recipient must perform certain security association procedures, such as re-authentication. We present in this paper an analysis of the epidemic broadcast delay in such context. The network, mobility and trust models presented in this paper are quite generic and allow us to obtain the delay component induced only by the security associations along a path. Numerical results obtained by simulations also confirm the accuracy of the analysis. In particular, we can observe from both simulation's and analysis results that, for large and sparsely connected networks, the delay caused by security associations is very small compared to the total delay of a packet. This also means that parameters like network density and nodes' velocity, rather than any trust model parameter, have more impact on the overall delay.