Large SDN networks will be partitioned in multiple controller domains; each controller is responsible for one domain, and the controllers of adjacent domains may need to communicate to enforce global policies. This paper studies the implications of the local network view of the controllers. In particular, we establish a connection to the field of local algorithms and distributed computing, and discuss lessons for the design of a distributed control plane. In particular, we show that existing local algorithms can be used to develop efficient coordination protocols in which each controller only needs to respond to events that take place in its local neighborhood. However, while existing algorithms can be used, SDN networks also suggest a new approach to the study of locality in distributed computing. We introduce the so-called supported locality model of distributed computing. The new model is more expressive than the classical models, and it is a better match with the features of SDN networks.
Rob Sherwood and Nate Foster (Eds.): HotSDN’13, Proceedings of the 2013 ACM SIGCOMM Workshop on Hot Topics in Software Defined Networking, August 16, 2013, Hong Kong, China, pages 121–126, ACM Press, New York, 2013