Software-defined networks (SDNs) have the potential to radically simplify the network management by providing a programmatic interface to a logically centralized controller. However, outsourcing the management to the software controller comes at a price, and good tradeoffs have to be found between the benefits of a fine-grained control and its costs. In this paper, we show that OpenFlow, the predominant SDN protocol, allows to implement powerful functions “in the south”, i.e., in the data plane. Our approach, called SmartSouth, can be used to reduce interactions with the control plane as well as to make the network more robust. Moreover, while rendering the data plane “smarter”, SmartSouth only relies on the standard OpenFlow matchaction paradigm; thus, the data plane functions remain formally verifiable—a key benefit of SDN. To demonstrate the potential of SmartSouth, we discuss four basic applications: (1) topology snapshot, (2) anycast, (3) blackhole- and (4) critical node detection.

Top