Virtual Switches Gain Ground

Learn the pros and cons of virtual network switching, and how to choose the right virtual switches for your enterprise.

By Julie Knudson | Posted May 20, 2013
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Virtual network switching is becoming increasingly important to the enterprise. I spoke to engineers and executives at Cisco, Dell, and VMware to learn what networking pros need to know to make the best virtual switch deployment decisions.

Virtual environments require virtual switches to handle the new types of traffic not addressed by their physical counterparts. Rather than moving through physical ports on a conventional switch, traffic in a virtual environment is “a virtual entity,” Dedi Shindler, senior manager of product management at Cisco, explained to Enterprise Networking Planet, and it requires a switch that understands how packets move outside the physical plane.

Most companies today already have hybrid environments, with physical components and virtual servers and machines acting in concert. “The virtual switches live in conjunction with physical switches,” said Arpit Joshipura, vice president of marketing and product management at Dell Networking. In this type of scenario, he explained, SDN-capable physical switches interoperate with virtual switches in an overlay model, giving administrators the ability to route traffic across the entire network. Depending on the enterprise’s architecture, virtual switches can manage traffic between only the virtual layers, or between both virtual and physical layers of the network.

Virtual switch market and adoption

In early 2012, the Enterprise Strategy Group, Inc. in Milford, Massachusetts, found that the virtual switch market consisted of two primary contenders, VMware and Cisco, and that most enterprises chose one or the other based on size. Larger organizations often went with Cisco, smaller ones with VMware. Big companies typically deployed a Cisco solution because “they wanted to have unified management over their networking space,” Bob Laliberte, senior analyst at ESG, told me. Smaller enterprises usually chose VMware’s virtual switches (the fact that they were free didn’t hurt). “The more limited the resources, the more likely it was that the person operating the switch was a server admin,” Laliberte said.

Bruce Davie, principal engineer of networking and security at VMware, said, “In some respects, the biggest competition we have is people not wanting to virtualize, and just wanting to stick with the status quo.” But recent developments in the virtual switch sector are beginning to shake things up a bit. Microsoft already has some network virtualization components within its software, and announcements by companies such as Juniper and Alcatel spinoff Nuage Networks are likely to bring offerings that are “broadly competitive” to what VMware is doing, Davie said.

Additional players are streaming into the market every day. While ESG’s earlier research showed that VMware and Cisco comprised the lion’s share of active deployments at the time, within the last 6 months Laliberte has seen “a flurry of virtual switches being developed and getting announced.” It seems that the virtualization market is an attractive pie; everyone wants a piece. Big and small companies alike are getting into the space, and enterprise administrators should watch for developments from Cisco, VMware, HP, IBM, NEC, Microsoft, Dell, Juniper, and Big Switch, among others.

The greatest adoption arenas for virtual switches are those environments that are highly virtualized. Laliberte said that 30 percent or less of most organizations’ environments were virtualized just a few years ago, and while some companies have since moved to a fully virtualized environment, Laliberte’s group is seeing rates that typically range from 30 percent to 50 percent today. “As we see that growth in—and the increased use of—server virtualization technology, the increase of virtual machines, and increased VM densities, we’re starting to see that virtual switches are playing a much larger role in that environment.”

Virtual switching: pros and cons

Deploying a virtual switch solution can make a number of IT tasks happen more efficiently. “I think probably the biggest pro that we see is improved time to market, or time to provision a new application,” Davie said. For example, rather than rolling out new applications in seven days, Davie reported that some customers have brought that time span down to 30 seconds. He admitted it sounds remarkable, but attributed it to those enterprises shifting from provisioning physical networking equipment one box at a time to an environment that supports pushing a button on a screen and provisioning an entire virtual network almost instantaneously.

One potential downside is a shift in how IT groups divvy up who does what. Virtual switch management may be a more natural fit for people used to administering servers and software. “It feels like a server admin function,” Joshipura explained. Those who are used to provisioning physical hardware may have a tougher time with the transition. And because many enterprises will be moving from a very familiar way of doing things to a new methodology, they should be mindful to develop processes that ensure network management tasks are still done correctly.

How to evaluate virtual switches for purchase

Enterprise administrators looking for a virtual switch solution have some legwork to do before inviting vendors in for their dog-and-pony shows. One consideration is what sort of hypervisor environment is currently in place. “If they haven’t started virtualizing the applications, I would say that’s a pretty important first step,” Davie explained. Though virtual switches can operate in a hybrid environment, Davie believes enterprises will reap bigger benefits when more of the application workloads are virtualized and running inside a VM. In addition, he encouraged IT groups to look for virtual switches that are not only hypervisor-agnostic, but also capable of supporting multiple hypervisors simultaneously.

In discussions with potential vendors, Shindler said IT administrators should carefully evaluate how today’s decisions will impact the enterprise’s options in the future, and ask questions about the amount of flexibility each potential solution has. “How versatile is my environment? Can I move to a different hypervisor?” Being locked in to any one vendor could limit what the enterprise can do in the future, or it could require additional purchases that might have been avoided with better planning today.

With the current emphasis on SDN and standards, Laliberte said there’s a fair amount of confusion about what’s open and what isn’t. He suggested that organizations find out whether the solution they’re considering is based on open standards, or if it’s proprietary to a specific vendor. This could impact a virtual switch’s ability to support future innovations and tasks. When it comes to overlays and network virtualization, remember that the possibilities are constantly expanding.

Among the next-level functionality coming out in the latest generation of virtual switches is the ability to do more than just Layer 2 tasks. The capability to support L2 through L4, and to tackle things such as routing and other higher-layer services, may very soon become the new baseline and a differentiator between providers. As enterprises evaluate the offerings currently on the market, it’s worth asking about each solution’s likely capability to handle in-the-works features such as these. A virtual switch buy is a forward-looking buy. Make sure the one you choose is ready for your network's future.

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