Performance of SDN Routing in Comparison with Legacy Routing Protocols

Legacy routing protocols such as OSPF and BGP have been developed very comprehensive, but its rigid complex system has been difficult to adapt to the fast growing Internet. The emergence of Software Defined Network (SDN) has brought hope for the solution of this problem. Benefit from the advantage of the centralized control, SDN can achieve efficiency in routing computation and fine-grained control for packets. However, is the performance of SDN routing really better than legacy routing when networks in churn? This paper studies the convergence performance of legacy routing mechanisms and SDN routing. We measure the performance in term of packet forwarding delay and convergence time after link/node failure. The experimental results show that the recovery of routing in SDN network has advantage in large-scale network topology. Compared with SDN routing, the routing convergence in legacy network is much more influenced by link delay. When the link delay of network is high and the network is large, the routing convergence time in SDN network is less than legacy network.