Algorithms for constructing haplotypes

Abstract

Software Defined Network (SDN) has attracted a significant attention due to its notable advantages including centralized control, simplified algorithms and efficient load balancing. It has been recognized that SDN can be widely applied in various network environments including enterprise networks, home and small businesses and data centers. OpenFlow, which is an implementation for the ow control in SDN, allows the centralized controllers to poll the traffic on each network link of the data plane network and make decisions to redirect the packets to the uncongested links. In order to deploy a scalable SDN in wide area networks, a number of controllers must be deployed in a logically centralized control plane. This controller placement issue has aroused much attention as it will significantly affect the SDN's performance in wide area networks. The controller placement problem tries to place k controllers in a given network to optimize performance metrics such as propagation latency, load distribution, network reliability and failure resilience. However, the quality of service (QoS) is always a primary concern of the network operators in the placement of SDN controllers. Since the SDN controllers are responsible to provide services for routers, the response time of controllers is an important QoS parameter of network operators. In this paper, we introduce the QoS-Guaranteed Controller Placement problem: Given a network topology and a response time bound, how many controllers are needed, where to place them, and which routers are assigned to each of the controller. We propose three heuristic algorithms: incremental greedy algorithm, primal-dual-based algorithm and network-partition-based algorithm. The proposed algorithms are tested and compared on the Internet Topology Zoo, a dataset of public available network topologies. Simulation results show that the proposed three methods have the similar performance on all input topologies.