OpenFlow: A Perspective for Building Versatile Networks

Abstract

In recent years, a remarkable number of innovative Internet services have been developed and successfully deployed on a global-scale. However, keeping up with this rate of innovation in the networking domain has been challenging. The increasing reliance on virtualization in data centers for instance, requires the backing of a sufficiently versatile network substrate. At the same time, network requirements are often highly application specific, making it difficult to develop one-fits-all solutions. Today, adding new functionality to an existing network infrastructure is an extremely complex and resource consuming task. While a number of vendor specific solutions allow operators to customize network devices to varying degrees, this functionality depends largely on the deployed hardware. As a consequence, a cross-platform interface allowing operators to program network devices is highly appealing. Additionally, network virtualization and programmability are widely regarded as an essential building blocks for enabling the evolution of the Internet infrastructure. Network virtualization, i.e. decoupling logical resources from the physical substrate, offers a number of benefits: increasing flexibility and reliability, reducing management complexity, as well as improving efficiency. OpenFlow, developed by the High Performance Networking Group at Stanford University is a promising example of an emerging standard which has the potential to enable programmability and virtualization support across various platforms, by providing a simple yet powerful interface for manipulating flow table entries using external controllers. The strict separation control and forwarding planes using a well defined abstraction layer, paves the way for novel networking applications while maintaining compatibility with legacy network components. This chapter aims to provide a summary of the concepts behind OpenFlow. It will also highlights key related frameworks and offers a brief look at the development of custom OpenFlow applications. Finally we introduce a number of OpenFlow-related projects and research initiatives.