Performance comparison of node-redundant multicast distribution trees in SDN networks

Some of the industrial processes with hard real-time constraints, such as those commonly found in the context of smart grids, require very reliable packet delivery and multicast. Solutions such as PRP assume deployments over redundant and dedicated networks. SDN gives us an unprecedented opportunity to obtain the same result by using a shared telecom infrastructure instead of privately owned networks. Nevertheless, there is a challenging question of how to provide node-redundant multicast-distribution-trees. We review existing graph-theoretical algorithms that were proposed for similar problems and propose three algorithms that are suitable for our smart-grid setting. Then, we evaluate their performance in the context of SDN networks. We use as metrics the number of forwarding rules that need to be installed on SDN switches, the number of hops between source-destination pairs given the installed forwarding rules, and the number of sources that can be placed in the network given the capacity constraints.