On offloading programmable SDN controller tasks to the embedded microcontroller of stateful SDN dataplanes

This paper presents a method to implement complex tasks into stateful SDN programmable dataplanes. In particular, the presented method proposes to use the internal microcontroller typically used to configure the programmable dataplane also to perform some complex operations that do not require to be executed on each packet. These operations can be executed on a set of data gathered by the dataplane and processed in a time scale that is much higher than the time window of a packet, but is much less than time scale needed for an external SDN controller. Moreover, the use of the configuration microcontroller instead of an external SDN controller to avoid the exchange of data on the control links permits a fine grain tuning of the operations to perform from the timing point of view (precise timestamping, low latency etc.). A set of measurements showing the feasibility of the method are presented, and a simple use case is described to show the effectiveness of this method to enhance the capability of stateful programmable dataplanes.