Using Path Label Routing in Wide Area Software-Defined Networks with OpenFlow

Separating the control and data planes has brought many advantages such as greater control plane programmability, more vendor independence, and lower operational expenses in Software-Defined Networking (SDN). SDN deployments are possible in a variety of contexts including Wide Area Networks (WANs). However, the large propagation delays between the controller and switches raise several concerns for WANs such as performance limitations, longer routing time for flows and sensitivity of the controller placement. To address this issue, we propose a path label routing approach in SDN-based WANs using OpenFlow. Through hybridizing traditional hop-by-hop routing with path label routing, we reduce flow routing time and controller state distributions. In addition, we present an implement method without modifications to OpenFlow. Finally a prototype is implemented as a proof of the method in OPNET simulator. Experimental results demonstrate that the approach can bring significant performance gains such as the reduction of state distribution and the sensitivity of controller placement in SDN-based WANs.