In a fabric model, the traffic moves horizontally across the network and virtual machine, "so it's more a concept of server-to-server connectivity." Fabrics are flatter and have no more than two tiers, versus legacy networks, which have three or more tiers, he says. Storage networks have been designed this way for years, says Kerravala, and now data networks need to migrate this way.
We look at it as an evolution in the architectural landscape of the data center network. Bob Laliberte, Senior Analyst, Enterprise Strategy Group
One factor driving the move to fabrics is that about half of all enterprise data center workloads in Fortune 2000 companies are virtualized, and when companies get to that point, they start seeing the need to reconfigure how their servers communicate with one another and with the network.
"We look at it as an evolution in the architectural landscape of the data center network," says Bob Laliberte, senior analyst at Enterprise Strategy Group. "What's driving this is more server-to-server connectivity ... there are all these different pieces that need to talk to each other and go out to the core and back to communicate, and that adds a lot of processing and latency."
Virtualization adds another layer of complexity, he says, because it means dynamically moving things around, "so network vendors have been striving to simplify these complex environments."
When data centers can't scale
As home foreclosures spiked in 2006, Walz Group, which handles document management, fulfillment and regulatory compliance services across multiple industries, found its data center couldn't scale effectively to take on the additional growth required to serve its clients. "IT was impeding the business growth," says Chief Information Security Officer Bart Falzarano.
The company hired additional in-house IT personnel to deal with disparate systems and management, as well as build new servers, extend the network and add disaster recovery services, says Falzarano. "But it was difficult to manage the technology footprint, especially as we tried to move to a virtual environment," he says. The company also had some applications that couldn't be virtualized that would have to be managed differently. "There were different touch points in systems, storage and network. We were becoming counterproductive."
To reduce the complexity, in 2009 Walz Group deployed Cisco's Unified Data Center platform, a unified data center fabric architecture that combines compute, storage, network and management into a platform designed to automate IT as a service, across physical and virtual environments. The platform is connected to a NetApp SAN Storage Flexpod platform.