A critical review of OpenFlow/SDN-based networks

The separation of the data and control planes simplify the implementation of SDN applications. The centralised architecture of a controller based on the OpenFlow protocol is appealing to the network operators. We have reviewed the concept of SDNs and its extension to optical networks, and constrained and unconstrained wireless access networks. The current status of the proposed and implemented SDN architectures is such that the fulfilment of a SLA is an open issue. This aspect is left to be tackled by the SDN applications and the proposed architectures do not provide means to describe the interplay between different technology domains. In this paper we make an in depth analysis of the current proposed architectures and identify important challenges to be addressed by a novel integrated SDN architecture.