Research On SDN Network Survivability

In recent years, SDN(Software Defined Network) has gradually became the research focus of network researchers. In SDN, the switch’s forwarding behavior is controlled by the software controller, rather than by the hardware itself in the traditional network. And network survivability is the ability to recover faster and better from failure event, such as link failure. And the research topic of this thesis is organically combine together two aspects, which is software defined network and network survivability, taking software defined network as research environment, and network survivability as research content. In SDN, it’s easy to write controller modules, implement network survivability, and do experiments to validate by simulation tool such as Mininet.In this thesis, the main purpose is to solve how to write controller modules to monitor the failure events, acquire the influenced business flow when SDN network suffers from network topological link failure events, and achieve the purpose of resuming the business flow in a short period of time.The thesis mainly studies two aspects of research on failure of network survivability problems based on SDN, one is the single link failure recovery and the other is massive failure recovery. It first starts from single link failure recovery problem, and analysis the survivability of SDN network itself, and link restoration recovery strategy, link protection strategy and fast reroute strategy respectively. Then it analysis recovery delay and traffice of business flow through network simulation, compare and verify the advantages and disadvantages of different strategies, come up with the conclusion which is by using fast reroute strategy, it can recovery business flow faster and better.The thesis also analysis the the possibility of massive link failure in SDN network, and study spanning tree strategy after the massive link failure based on this background. Through network simulation, by using spanning tree strategy, it can restore the influenced business flow faster.The main achievements of this paper mainly include the following two aspects. On the one hand, after the analysis of the advantages and disadvantages of link recovery and link protection strategy, the thesis creatively proposes to solve the problem of single link failure by using the fast re routing strategy. On the other hand, it uses spanning tree method to solve the problem of massive link failure in SDN network.