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.