Towards SDN Fault Tolerance using Petri-Nets
Wael Hosny Fouad Aly, Yehia Kotb · 2018
Software defined networking (SDN) depends on separating control and data planes. Vendors seek flexible and ease-for-use networks. SDN has introduced two main functions; centralized control and programmability which have become the pillars of SDN. In this paper we use SDN as a centralized architecture which is composed of a master-controller connected to a set of slave-controllers. Switches connect to slave-controllers forming clusters. In this paper, we introduce a new petri-net based mathematical framework for SDN fault tolerance. The proposed model is called Fault Tolerance using Petri-nets for SDN networks (FTPNSDN). Simulation results show a significant improvement in the availability of the network when compared to a reference model. The model shows stability after controller failures. Petri net capability functions are used to sort the backup controllers to take over in case of failure in descending order. This helps the switch to be aware of the next controller to take over next and avoid interruption of service. Results show an improvement of above 10% improvement in terms of transition time before another controller takes over which leads to an improved fault tolerance of the network. Packet delays are reduced by 12% when compared to Hyperflow reference model.