What is SDN Network Element

The connection of billions of devices to the internet poses numerous challenges to the networking infrastructure. The traditional networking paradigm is anticipated to be unable to cope with a scenario of myriad heterogenous devices connected through both wireless and wired links. The mobility and instability of a significant portion of the devices of the IoT demand a flexible and agile response of the network to adapt and keep the appropriate policies in effect. Software-defined networking (SDN) moves the intelligence of the network to a central controller with a global vision of the network capable of issuing timely instructions to the network nodes to accommodate the constant changes. This chapter presents the SDN paradigm, covering its architecture, functional blocks, interfaces, and protocols. The focus is put on the application of SDN to IoT environments supporting different applications, each with its specific difficulties, exploring current trends to tackle the identified challenges.