Extreme Networks has unveiled a blueprint for migrating data centers from the physical world to virtualisation, and then ultimately to cloud computing.

At the Gartner Data Center Conference in Las Vegas, Extreme disclosed its data centre evolution strategy, which is in sharp contrast to that endorsed by Cisco. Extreme's approach seeks to eliminate virtual switching at the server level while Cisco proposes adding that element to data centre servers, specifically the blade servers within its new Unified Computing System platform.

Extreme's blueprint is expected to collide with Cisco's Data Center 3.0 strategy, Force10 Networks' Virtualisation Framework, elements of Juniper's Stratus project and architectures pitched by Brocade, HP and other data centre switching competitors.

It's intended to assist in evolving data centres to wide-scale virtualisation and cloud computing "without forcing certain technologies or operating methodologies" on users, says Gordon Stitt, Extreme chairman and co-founder.

Extreme's plan is built on four "pillars" of data centre infrastructure and operations: physical, efficiency, scalability and automation/customisation.

Physical deals with network topology, switching tiers, bandwidth and performance; efficiency involves integration, support, and management of virtual machines and hypervisors; scalability revolves around switching capacity to support thousands of VMs and applications; and automation/customization supports configuration and extensibility through XML and APIs.

Extreme is addressing the first pillar through its existing stackable and modular switching lines -- the Summit x450 and x650 switches for top-of-rack server access applications and the modular BlackDiamond 8800 series for the core.

Stacking allows switch capacity and density to increase while also enabling the stacked configuration to be managed as a single switch, with aggregated links providing increased bandwidth and redundancy.

Extreme switches are also 40/100G Ethernet "ready" through the inclusion of an expansion slot for uplinks, Stitt says. He expects Extreme to have 40/100G modules for the switches around mid-2010.

For efficiency, Extreme proposes that switches become "VM aware." Extreme currently supports VMware's hypervisors with plans to add others to the mix. This will allow the company's switches to dynamically track and manage VMs and apply policies as VMs move across the network.

The differentiator, though, comes in the scalability pillar. Today, vendors such as Cisco and even the leading blade server companies -- IBM, HP and Dell -- propose adding a software-based virtual switch to the server itself to handle the growing number of VMs. Cisco's instantiation of this is VN-Link and the Nexus 1000V software-based switch.

But virtual soft switches on servers add another element and layer of management complexity to the virtual data center, Extreme asserts. Meanwhile, moving -- or keeping -- switching in the network reduces management complexity while increasing switching performance, the company says.

So Extreme proposes keeping switching in the switch and not moving it to the server. The company is a proponent of an emerging IEEE specification called Virtual Ethernet Port Aggregation (VEPA), which, among other attributes, is designed to eliminate the large number of network and virtual switching elements that need to be managed in a data center.

VEPA does this by allowing a physical end station to collaborate with an external switch to provide bridging support between multiple virtual end stations and external networks, according to a presentation on the IEEE website.

"A hardware switching is very predictable" in performance and behaviour, Stitt says. "Software or server-based switches can be unpredictable."

Work on standardising VEPA began last month, Stitt says, adding that Extreme plans to be one of the first vendors to adopt it once it is ratified.

Extreme still needs to flesh out its data center strategy with a plan around network and storage convergence, however. Stitt says that will be forthcoming and will include Extreme's views and plans around technologies and standards like Converged Enhanced Ethernet and FibreChannel-over-Ethernet.

Regarding the latter, Stitt believes it to be an interim, perhaps short-term remedy."If FibreChannel is already installed, I wonder if FCoE would be a good choice," Stitt posits. "Ethernet will ultimately carry storage traffic. Ethernet ultimately wins."