Tackling Multiple Byzantine Failures in Optical Networks Routed by means of Ant Colony Optimization

Byzantine failures in the routing protocol may disrupt the normal operation of the network, where authenticated nodes exhibit arbitrary or defective behavior. Ant Colony Optimization (ACO)-based routing algorithms are especially susceptible to those kinds of failures. By incorporating crankback re-routing extensions into the ACO algorithm, resilience against byzantine failures can be achieved. In this work, we evaluate the crankback mechanism and its overhead in the presence of many nodes of a wavelength-switched network engaging in three different types of byzantine behavior: misdirection of forward ants, dropping of forward ants, and dropping of backward ants. Simulations have demonstrated that the crankback mechanism can effectively mitigate the impact of multiple byzantine failures on the blocking probability without requiring an important increase of the path length or the setup time of the established lightpaths.