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Researchers show off advanced network control technology

OpenFlow technology can optimize routes through networks to meet critical policies

By , Network World
October 29, 2008 05:49 PM ET

Network World - Researchers can adjust network infrastructure to boost bandwidth, optimize latency and save power using an experimental technology called OpenFlow.

OpenFlow is in the proof-of-concept stage but someday could 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 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 does two things. It 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, he 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, HP, Juniper and NEC have added OpenFlow to switches and routers being used in the project. OpenFlow is not generally available.

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 optimized 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 is being demonstrated this week at Global Environment for Network Innovations (GENI) Engineering Conference at HP Labs in Palo Alto. Researchers in the OpenFlow Consortium are demonstrating the feature in an experimental network between California and Japan. In the demo, players in both countries are playing a computer shooting game, and OpenFlow is being used to locate a virtual server on the network so minimize 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 equalize latency, McKeown says. While the demonstration is not a practical business application of the technology, it does show some of its capabilities, he says.

Read more about lans & wans in Network World's LANs & WANs section.

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