Bandwidth-delay constrained routing algorithms for backbone SDN networks

In this paper we analyzed suitability of different routing algorithms for establishing bandwidth-delay constrained traffic tunnels in SDN backbone networks. Bandwidth rejection ratio was used as indicator of algorithm´s ability to efficiently utilize network resources. Through set of simulations on two real backbone topologies we showed that network topology can affect algorithm´s performance, and can lead to biased results. Also, we pointed out problem of high complexity of existing traffic engineering (TE) solutions, which often cannot perform calculations in real-time. Since in SDN networks the controller processing latency can turn out to be a non-negligible factor in the total round-trip latency, we explained heuristic techniques for reducing computation time of bandwidth-delay constrained algorithms and provided illustrative results showing how they impact BRR performance.