ABSTRACT
This research is aimed at the development of a modified East-West Interface for distributed control plane in Software Defined Network (SDN) for Wide Area Network (WAN). The East-West Interface is important in achieving communication across a Software Defined WAN, to enable scalability and distribution of the control plane. The Communication Interface for Distributed Control Plane (CIDC) was developed to ensure communication in WANs. However, the interface does not address the synchronization of different modules in the controller. This synchronization enables a consistent high availability, policy updating and efficient communication among controllers, needed for SDN to scale in a WAN environment. The modified-CIDC (mCIDC) is therefore developed using the ISyncService that ensures synchronization of state across the different modules in the controller, and among controllers in the WAN. The performance of the mCIDC and CIDC was compared using captured TCP (Transmission Control Protocol) packets, TCP errors and inter-controller communication overload (ICO). The results indicated that for Claranet_2, mCIDC showed a better performance in minimizing the number of Captured TCP Packets, TCP Errors and ICO by 26.55%, 17.89%, and 19.35% respectively when compared with CIDC. While for Claranet_3; 15.82%, 21.60% and 29.25% for Captured TCP Packets, TCP Errors and ICO respectively. For network policies with Claranet_2, mCIDC indicated a better performance in minimize Captured TCP Packets, TCP Errors and ICO by 16.34%, 17.77% and 44.99% respectively. While network policies with Claranet_3; 15.51%, 29.85% and 22.98% for Captured TCP Packets, TCP Errors and ICO respectively. This shows that the mCIDC ensures communication by transmitting the necessary required packets (information) among controllers with reduced TCP errors and fewer overloads.