Can open flow make transport networks smarter and dynamic? An overview on transport SDN

The growth of intra data center communications, cloud computing and multimedia content applications force transport network providers to allocate resources faster, smarter and dynamically. Software-defined Networking (SDN), has been proposed to create a unified control plane for transport networks (Transport SDN). This article presents an overview on Transport SDN proposals based on OpenFlow, the de facto SDN protocol. OpenFlow is at the forefront of the Transport SDN models and several testbeds have proved the implementation of a unified control plane for multi-domain and multi-technology optical transport networks. We show how OpenFlow can be enabled in current and future network devices through agents and new hardware respectively. Transport SDN can boost the programmability and scalability of the network., increase the network intelligence and allow for dynamic resource allocation and restoration. The review highlights a rapid development of Transport SDN, which seems to tackle the problems that GMPLS encountered for commercial deployment. Finally a comparison between the main research efforts towards a multi-domain transport SDN is given.