  To effectively tackle the security threats towards the Internet of things, we
propose a SOM-based DDoS defense mechanism using software-defined networking
(SDN) in this paper. The main idea of the mechanism is to deploy a SDN-based
gateway to protect the device services in the Internet of things. The gateway
provides DDoS defense mechanism based on SOM neural network. By means of
SOM-based DDoS defense mechanism, the gateway can effectively identify the
malicious sensing devices in the IoT, and automatically block those malicious
devices after detecting them, so that it can effectively enforce the security
and robustness of the system when it is under DDoS attacks. In order to
validate the feasibility and effectiveness of the mechanism, we leverage POX
controller and Mininet emulator to implement an experimental system, and
further implement the aforementioned security enforcement mechanisms with
Python. The final experimental results illustrate that the mechanism is truly
effective under the different test scenarios.
