FitSDN: Flexible Integrated Transactional SDN

Extremely popular with the research community, the SDN has indeed matured and mostly resolved the original performance doubts. The next frontier is to make it popular with the end users, i.e. the administrators and the developers, without sacrificing the performance. Recent distributed SDN proposals still come with a number of design decisions that appear limiting with respect to the ease of administration, application development, and performance. For instance, opting for strong consistency in the controller design results in a complex network administration and can severely impact the performance; choosing the eventual consistency delegates the real problems to application developers: while this design makes the administration lighter, to get the expected behaviour and performance, it requires developers to have profound distributed systems understanding. We argue that this is a bad tradeoff. Consequently, we design, implement and evaluate a novel Flexible Integrated Transactional SDN (FitSDN) that achieves the ease of development and administration, as well as good performances. In a nutshell, FitSDN eliminates the replication of critical network state in the controller instances and taps switch flow tables under a transactional semantics instead. FitSDN enables simple and intuitive APIs that permit SDN application developers to focus on the actual application logic. Comparing FitSDN to a popular distributed controller, FitSDN achieves around 4 times faster responses to network events.