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Is OpenFlow a go?

Interop 2011 could have been called The OpenFlow Show.

Vendors were hawking OpenFlow switches and controllers, and a lab demonstration on the show floor displayed the traffic management technique and applicability among multivendor switches. It was the first significant demonstration of the technology at the network industry's big trade show and indicates the growing momentum behind OpenFlow.

"OpenFlow is the first viable approach to software defined networking (SDN), and you can solve problems faster using SDN," says Alex Reimers, a member of the technical staff at startup Big Switch Networks, a maker of OpenFlow switches and controllers. "People want to control their own networks."

BACKGROUND: OpenFlow opens new doors for networks

OpenFlow is a protocol that enables SDN, which means that users can define flows and determine what paths those flows take through a network, regardless of the underlying hardware. OpenFlow can take control of how traffic flows through a network out of the hands of the infrastructure -- the switches and routers -- and put it in the hands of the network owner, individual users or individual applications.

This capability could allow users to craft policies that find paths with available bandwidth, less latency or congestion, and fewer hops. Participants in the OpenFlow lab at Interop say it is particularly useful for load balancing, flow control and virtual networking in data centers, private clouds and campus LANs where devices are multiplying and straining network topologies.

"It's really just a protocol and not a complex protocol, but it enables complex functions," says Jed Daniels, director of product development at OPNET Technologies, one of the demonstrators in the OpenFlow lab.

OpenFlow is an open source project borne of a six-year research collaboration between Stanford University and the University of California at Berkeley. Last month, this approach was embraced by a wide range of big-name industry players as they formed the Open Networking Foundation to push the protocol.

Fifteen vendor participants in the Interop lab were showing beta products. They included Big Switch, Broadcom, Brocade, Citrix, Dell, Extreme Networks, Fulcrum, HP, IBM, Juniper, Marvell, NEC, NetGear and NetOptics. Pronto Systems, a maker of switches that can run OpenFlow software, contributed products that are already shipping.

The demonstration showed OpenFlow controllers, switches acting as OpenFlow agents and OpenFlow applications performing functions like bandwidth calendaring, network virtualization, load balancing, virtual switching and virtual network "slicing." Separately, individual vendors discussed plans to support or study the technology to potentially configure their switches as OpenFlow controllers or agents.

FAQ: What is OpenFlow and why is it needed?

HP, for example, plans to stuff its 5406 switch chassis with server blades to configure the switch as an OpenFlow controller to manage and monitor quality-of-service delegations among OpenFlow switch clients. The company does not have a timeframe, however, for delivering this capability on the 5400 series switches, says Erik Papir, a technical marketing official in HP's networking group.

Papir likens OpenFlow to VMware's vSphere hypervisor software for implementing and managing virtualization in a data center or enterprise network.

"It's more of a control plane or management solution than a switching solution," he says. "It gives you vendor independency and a single pane-of-glass view."

Extreme has an OpenFlow agent software module for its XOS operating system in customer trials. It's being tested with OpenFlow controllers from NEC and Big Switch Networks, says Shehzad Merchant, Extreme senior director of strategy.

Start-up Gnodal, a maker of 1RU 10G and 40G Ethernet top-of-rack and fabric switches, will ship an OpenFlow agent by the end of the year. The company says there are still wrinkles to iron out with OpenFlow 1.1, though.

"There are deployment over larger scale and production use issues," says Fred Homewood, Gnodal CEO. "It's fine on medium scale but we're looking at hundreds of thousands of ports."

Homewood believes the Open Networking Foundation will address OpenFlow's scale issues.

OpenFlow skepticism

Indeed, there is still some caution in the industry regarding OpenFlow despite its growing momentum. Enterasys has the same scalability concerns that Gnodal does. Cisco is still investigating the technology and its membership in the ONF is mostly for exploratory purposes, says Joel Conover, Cisco senior marketing manager.

Arista Networks is waiting for customer demand to pick up before jumping on board, says CEO Jayshree Ullal.

"We're already abstracting flow control with our EoS operating system" and third-party controllers, Ullal says.

She says the OpenFlow crowd has to be careful not to pitch the technology as a networking panacea.

""The task has to be ambitious but realistic," Ullal says. "If they are trying to solve every use case it will become hype."

And Avaya believes its switches can do the same things OpenFlow can do just by integrating programmable network processors. There's also the sticky issue of security, especially when opening up the forwarding tables of multiple switches from multiple vendors.

"We have a curiosity about OpenFlow at the moment," says Bill Seifert, CTO of Avaya Data Solutions, intimating that it's an interesting academic exercise. "We're waiting to see what customers think about it. It's an interesting idea for flexibility. But security for OpenFlow ... OpenFlow will fit where you need less security, and have less vulnerability."

Still, Seifert says the company is considering joining the ONF.

To the Interop lab participants, the selling points of OpenFlow are apparent.

"No more VLANs, no more management overhead, and simple application rollout" by programming switches to forward traffic any way you define, says Big Switch's Reimers.

Read more about lan and wan in Network World's LAN & WAN section.


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