Who Needs It
While the most intense interest in OpenFlow is in large-scale data center applications, there's already speculation about how OpenFlow-based SDNs can benefit other industries. The fact that Deutsche Telekom and Verizon are among the founders of the ONF provide some hints at next applications.
In mobile networks, OpenFlow can help solve a notoriously hard problem in IP: monitoring, metering, and servicing user traffic. In service provider networks, OpenFlow may provide a more workable alternative to MPLS traffic engineering.
More broadly, the ability of a network operator to create custom functions applicable to its own network, and then apply those functions to switches from multiple vendors, is the true promise of SDNs. Technology users have always found surprising ways to use the tools available to them, innovating from the bottom up rather than limiting themselves to top-down vendor systems. An open instruction set could accelerate that innovation.
OpenFlow version 2.0 is in the works, bringing with it a generalized networking instruction set, as well as a standardized API to the network operating system that's planned for 2012 release. That upgrade would make it easier for third-party network management systems and data center provisioning tools to interact with OpenFlow controllers. Manufacturers of commodity switches, including Hewlett-Packard and Extreme Networks, are starting to line up behind OpenFlow and SDNs, as are new vendors such as Nicira Networks and Big Switch Networks that are focused on network control systems.
OpenFlow has the right combination of industry and academic backing to ensure that its development and evolution continue. It has the potential to turn the networking world on its head by disrupting the market positions of high-end router and switch vendors, including Cisco and Juniper. Or those vendors have the potential to turn this trend to their advantage (see related story, p. 33).
While still in its infancy, OpenFlow has already been used to demonstrate fixes to old problems. Conventional Ethernet switching architectures have long been stuck in inefficient, inflexible tree structures. Those don't look sustainable for a lot of what companies will want to accomplish. OpenFlow can be expected over the next few years to change the landscape of large data center and enterprise campus networks.