Where Do SDNs Fit in the Data Center?

As CIOs try to make sense of the hype surrounding software-defined networks (SDNs) and their potential in data centers, some experts and vendors say IT leaders are looking for answers in all the wrong places.

Tue, September 17, 2013


While most of the conversation about software-defined networks (SDNs) focuses on their impact on the data center -- virtualizing networks to cut hardware and personnel costs, reduce on-site footprints, remove bottlenecks and traffic flow problems and make network management easier -- the true benefit of SDNs may lie outside the data center.

software-defined networks

The true value of SDNs may be for managed service providers (MSPs) and for enterprises with multiple branch offices, says Kurt Marko, a networking consultant and analyst.

How SDNs Work

SDN technology removes the intelligence from traditional networking hardware and delegates network decision-making capabilities to the server, Marko says. The technology decouples the data layer (the actual information traveling on a network) from the control layer (the technology that determines how, when and where that information flows) to make independent control of each layer possible without expensive, complicated hardware and software (i.e., routers and switches and the professionals that manage them).

Marko says that most of this network control and management technology already exists, and is currently being used by large enterprises in the data center. Enterprise networks are built in such a way that they currently provide high switching capacity between systems (what's known as east-west traffic flow) and to outside gateways (what's known as north-south), Marko says.

Even if enterprises aren't currently using high-capacity, efficient solutions, they're most certainly considering it or are in the process of deploying high-performance and high capacity networks in the data center.

So, if that's the case, why all the hype? Some of it really is just that -- hype, Marko says, as everyone tries to jump on the bandwagon and cash in on the newest, hottest acronym bandied around in IT circles, even though it may not make sense for some enterprises. And some of it is simply confusion about how networks function and how SDN technology can benefit highly trafficked networks.

When and Where SDNs Make Sense

SDNs, Marko says, have great potential to speed up networks that encounter highly variable traffic, like retail sites that may see seasonal or sale-related spikes in traffic, sites that are video- or audio-heavy.

SDNs are also particularly well-suited for MSPs that handle customers' networks, since those customers may have unpredictable traffic increases or decreases, he says.

"It's unclear right now how valuable SDN will be to the typical enterprise data center," Marko says. "What is more clear is the technology's value for service providers and big cloud providers because their network traffic can be much more variable and unpredictable depending on what kinds of data are running over them, what types of applications are used and what types of end-user profiles they see," Marko says.

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