METHOD AND APPARATUS FOR RESILIENT ROUTING OF CONTROL TRAFFIC IN A SPLIT-ARCHITECTURE SYSTEM

The invention is a routing algorithm characteristic that minimizes the weight, meaning that the probability that a node is disconnected from the controller in case of a failure in the network is minimized. The first algorithm used in the invention is an approximation algorithm for finding the controller routing tree that provides maximum resilience in the network. The algorithm is referred to herein as the Maximum Resilience (MR) algorithm. The heuristic MR algorithm selects a shortest-path tree as a starting point and modifies the tree in order to improve resilience. The output of the MR algorithm is not necessarily a shortest-path tree, but provides more resilience compared to the initial tree. The RASP algorithm provides a shortest-path tree with improved network resilience compared to other possible shortest-path trees.