Advanced network control technology demoed

Testing without disrupting network apps is achieved

An experimental technology called OpenFlow has been shown to adjust network infrastructure to boost bandwidth, optimise latency and save power.

OpenFlow is still at proof-of-concept stage, but may in the future be used in business networks to engineer traffic, says Nick McKeown, an associate professor of electrical engineering and computer science at Stanford University.

OpenFlow is part of the Clean Slate initiative, set up at Stanford and supported by several networking and telecommunications vendors, to consider how the internet might be re-engineered to make it more responsive to how it is actually used.

Researchers devised OpenFlow as a way to test out new network protocols on existing networks without disrupting production applications. The only other option is to set up separate infrastructure on which to run experiments, a costly alternative.

OpenFlow lets users define flows and determine what path those flows take through the network — all without interrupting normal traffic.

Policies can be crafted to find paths with certain characteristics such as more bandwidth, less latency and fewer hops so they use up less power, McKeown says.

The technology consists of three parts: flow tables installed on switches, a controller and a proprietary OpenFlow protocol for the controller to talk securely with switches. For the purposes of OpenFlow development, Cisco Systems, HP, Juniper and NEC have added OpenFlow to switches and routers being used in the project.

With the feature, flow tables are set up on switches. Controllers talk to the switches via OpenFlow Protocol, which is secure, and impose policies on flows. So, for example, a simple flow might be defined as any traffic from a given IP address. The rule governing it might be to route the flow through a given switch port. With its knowledge of the network, the controller could set up paths through the network optimised for speed, fewest number of hops or reduced latency, among other characteristics, McKeown says.

With current switches and routers, policies within them controlled by proprietary software determines the path traffic takes. OpenFlow can take control of how traffic flows through the network out of the hands of the infrastructure — the switches and routers — and put it in the hands of the network owner (such as a corporation), individual users or individual applications. McKeown says.

OpenFlow was demonstrated recently at Global Environment for Network Innovations (GENI) Engineering Conference at HP Labs in Palo Alto. Researchers in the OpenFlow Consortium demonstrated the feature in an experimental network between California and Japan. In the demo, players in both countries played a computer shooting game, and OpenFlow was used to locate a virtual server on the network so as to minimise the average latency each player experiences.

In the demo, the game server is located on a virtual machine. Using OpenFlow, the virtual server copies itself to another physical server at the optimal location in the OpenFlow network to equalise latency, McKeown says. While the demonstration is not a practical business application of the technology, it does show some of its capabilities, he says.

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