Reducing SDN/openflow control plane overhead with blackhole mechanism

Software Defined Networking is getting a lot of attention in recent years especially with OpenFlow implementation. Although the Controller centered paradigm brings great advantage to management and visibility, it also may cause some scalability and performance issues on Switch-Controller interface. We propose the "blackhole mechanism" as an alternative to reduce the communication overhead of OpenFlow operation in reactive mode. We also discuss the effect of UDP traffic over the control plane communication. In addition, we describe the problem of matching-rule expiration due to hard timeout regardless the traffic type. Finally, we evaluate the communication overhead through an experimental setup using Pantou OpenFlow switch and POX Controller running L2_learning application.