Link-Prioritized Network State Information Collection in SDN.

Routing in Software Defined Networking (SDN) requires the SDN controllers to obtain the current dynamic network state information (NSI) as accurately as possible while reducing protocol overhead. To balance the trade-offs between the accuracy and protocol overhead, the SDN controllers usually implement a periodic NSI collection design where they obtain the dynamic link-state information from each switch at a predetermined rate. To improve the accuracy of NSI while minimizing the protocol overhead and providing better load balancing among multi-controllers, we propose a link-prioritized NSI collection design and compare it against the existing periodic NSI collection design. Using a dynamic routing algorithm on RYU SDN controller and the Mininet emulator, we compare our design against existing periodic NSI collection design. We observe that the proposed link-prioritized NSI collection design significantly reduces the protocol overhead without sacrificing the routing performance in terms of throughput or accepted bandwidth request. Moreover, our design results in better packet loss because it can quickly and accurately obtain NSI.