SDN: Software Defined Networks

Chapter 3. OpenFlow

Introduction

Chapter 2 reviewed the control and data planes. In this chapter, a lot of our focus will be on the continuously evolving OpenFlow proposal and protocols, viewed by many as the progenitor of the clean slate theory and instigator of the SDN discussion, but we will also discuss, in general terms, how SDN controllers can implement a network’s control plane, and in doing so, potentially reshape the landscape of an operator’s network.

OpenFlow was originally imagined and implemented as part of network research at Stanford University. Its original focus was to allow the creation of experimental protocols on campus networks that could be used for research and experimentation. Prior to that, universities had to create their own experimentation platforms from scratch. What evolved from this initial kernel of an idea was a view that OpenFlow could replace the functionality of layer 2 and layer 3 protocols completely in commercial switches and routers. This approach is commonly referred to as the clean slate proposition.

In 2011, a nonprofit consortium called the Open Networking Foundation (ONF) was formed by a group of service providers^[35] to commercialize, standardize, and promote the use of OpenFlow in production networks. The ONF is a new type of Standards Development Organization in that it has a very active marketing department that is used to promote the OpenFlow protocol and other SDN-related efforts. The organization hosts an annual conference called ...