This chapter introduces OpenFlow and its role in the SDN ecosystem and how it works in a computer network. It shapes the required knowledge prior to the actual setup of an experimental environment. The notion of flow forwarding, OpenFlow functions, what OpenFlow tables can do, and features and limitations of OpenFlow are recovered in this chapter.

We will cover the following topics:

• Activities around SDN/OpenFlow
• Building blocks of an SDN deployment
• OpenFlow messages
• The Northbound interface