In-Band Synchronization for Distributed SDN Control Planes

Control planes of forthcoming Software-Defined Networks (SDNs) will be distributed: to ensure availability and faulttolerance, to improve load-balancing, and to reduce overheads, modules of the control plane should be physically distributed. However, in order to guarantee consistency of network operation, actions performed on the data plane by different controllers may need to be synchronized, which is a nontrivial task. In this paper, we propose a synchronization framework for control planes based on atomic transactions, implemented in-band, on the data-plane switches. We argue that this in-band approach is attractive as it keeps the failure scope local and does not require additional out-of-band coordination mechanisms. It allows us to realize fundamental consensus primitives in the presence of controller failures, and we discuss their applications for consistent policy composition and fault-tolerant control-planes. Interestingly, by using part of the data plane configuration spa...

• Type: Journal
• Year: 2016
• Where: CCR
• Authors: Liron Schiff, Stefan Schmid, Petr Kuznetsov
• Keywords: CCR 2016, Software Engineering