Multi-level Hierarchical Controller Placement in Software Defined Networking

Abstract

AbstractSoftware Defined Networking (SDN) is a widely used network architecture. It separates the controller logic (or control plane) from forwarding plane (or data plane) to manage the whole network and it enables the network scalability and programmability. One of the most significant challenges in Software Defined Networking (SDN) is the Controller Placement Problem (CPP), which tries to specify the minimum number of controllers and their optimal location.In our study, we extend the methodology based on K-means and K-center algorithms to solve the Controller Placement problem (CPP) into a Multi-level Hierarchical Controller Placement Problem (HCPP), where the Super Controller (SC) is in the top-level, some Master Controllers (MCs) are in the intermediate level and the Domain Controllers (DCs) are at the bottom level. The optimization metric is the latency between controller and switches assigned to it and the latency for controller to controller communication.The proposed architecture and methodology is applied on Western European NRENs topology taken from Internet Topology Zoo. The entire network topology is divided into small scale networks (Clusters) and for each cluster, the optimal number of controllers (Domain Controllers) and their placement is found. A second optimization identifies the optimal number of Master Controllers and their optimal placement.The results validate the methodology and show its feasibility on large networks and different domains. A useful use case may be the deployment of hierarchical levels of controllers for the enforcement of very precise routing policies through different domains.KeywordsSoftware Defined NetworkControllers placementLatency optimizationHierarchical Control PlaneMultistage optimization