Overview

OpenFlow separates the data forwarding and routing decision functions. It keeps the flow-based forwarding function and employs a separate controller to make routing decisions. A switch communicates with the controller through an OpenFlow channel. An OpenFlow channel can be encrypted by using TLS or run directly over TCP. An OpenFlow switch exchanges control messages with the controller through an OpenFlow channel to perform the following tasks:

• Receive flow table entries or data from the controller.

• Report information to the controller.

Unless otherwise stated, a switch refers to an OpenFlow switch throughout this document.