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Choosing the right software-driven network technology

The software-driven network can drive efficiency and flexibility, but network pros first need to identify the problems they're trying to fix to choose the right technology options.

When CIO Alan Crawford joined City & Guilds Group in 2016, the U.K.-based vocational training nonprofit had made a slew of recent business acquisitions as part of an effort to diversify its offerings and expand its global reach. The organization, founded in 1878 by a collection of London fishmongers, goldsmiths and other liverymen, now operates in more than 100 countries across six continents. And while geographic expansion may have proven strategically wise, it presented some early challenges for the new CIO.

One central issue involved implementing software-driven network elements to fix connectivity among company locations. A few months into his tenure as CIO, Crawford transitioned a recently acquired New Zealand company to Microsoft Office 365, the productivity suite preferred throughout City & Guilds. But when it joined the service, which routes traffic to data centers in Europe, the company's connectivity suffered a major hit. Suddenly, basic tasks like sending emails, making Skype calls and sharing documents became time-consuming and frustrating. Performance and morale suffered.

Crawford said CIOs are measured more by what doesn't work, whether it's a projector in a single conference room or connectivity in an office on the other side of the world. He knew he needed to fix the problem, and fast. "We looked at all our existing, traditional technologies and approaches, and we were drawing a blank," he said.

Enter software-defined WAN. Managed service provider Aryaka Networks approached the initially wary City & Guilds network engineers with a try-it-before-you-buy-it pitch. But when the organization installed the equipment box on site, Crawford said the New Zealand team's performance issues immediately resolved across every one of its Office 365 applications.

The software-driven network is becoming more of a reality, as City & Guilds discovered. But while software-defined networking technology first became a way to separate the network's control plane from its data plane, the term has grown to more broadly suggest programmability, automation or functional separation of a network's "brains" from its "muscle," actions that result in greater flexibility and responsiveness, whether in the data center or the wide area network.

Enterprise network professionals have a range of new terms to learn and understand that relate to the software-driven network. From SDN and software-defined WAN (SD-WAN) to network virtualization, network functions virtualization and virtual network functions (VNFs) -- enterprises face a slew of options aimed at fundamentally changing the way networks are designed, built and managed. While it's easy to be bogged down by the alphabet soup of software-defined technologies, network managers should first figure out the problems they want to solve before identifying which new technology to use, analysts say.

What's in an SDN name?

SDN, SD-WAN, network virtualization and VNFs each have subtle, but important differences.

Software-based networking has experienced particularly rapid, widespread adoption in the WAN. In a recent survey of 300 networking professionals, the research firm Enterprise Strategy Group found that three in four either already use SD-WAN or have plans to do so.

SD-WAN can dramatically reduce branch outages; provide more bandwidth at lower cost, as in the case of City & Guilds; and improve and simplify network management, said John Burke, CIO and principal analyst at Nemertes Research.

SD-WAN adoption drivers

"SD-WAN implements all the virtuous things about SDN: centralized management, distributed execution, software control," Burke said. "It can be stretched over virtual or physical nodes, and it provides network virtualization."

Related to but not synonymous with SDN, network virtualization refers to the abstraction of logical network behavior from its corresponding hardware. In the data center, for example, VMware NSX allows network managers to efficiently create separate and secure virtual networks on top of shared physical gear, a function known as microsegmentation.

Similarly, virtual network functions abstract and consolidate specific network applications that traditionally run on discrete boxes, such as routers or firewalls.

So in an alphabet soup of software-defined acronyms -- SDN, SD-WAN, VNFs -- how do managers know which one spells s-u-c-c-e-s-s for any particular software-driven network? Lee Doyle, principal analyst at Doyle Research, suggested another question might be more relevant.

Pro tip: If the network keeps working OK, you won't get budget for [an] SDN upgrade.
Greg Ferronetworking expert blogger

"It's more about the use case than the technology," he said. "What problem are you trying solve?"

Networking blogger Greg Ferro articulated a similar sentiment, albeit more pointedly. He suggested major network problems ultimately make the strongest case for software-based networking investments.

"Pro tip: If the network keeps working OK, you won't get budget for [an] SDN upgrade," Ferro tweeted. "Your career moves ahead when the network keeps breaking and you have to replace it."

City & Guild's Crawford, who was largely unfamiliar with SD-WAN technology before implementing it, said he has learned to regard any new product or service with a healthy level of skepticism. But the way SD-WAN solved connectivity problems for the acquired New Zealand company has changed his approach to network design.

"For us it was almost like a tactical fix, but it's now influencing our strategic thinking around networking," Crawford said, adding as City & Guilds' various existing MPLS contracts come up for renewal, it will consider ditching the leased lines for SD-WAN.

Whatever the network problem at hand, Burke suggested enterprise network engineers prioritize fully centralized management capabilities and high levels of automation. They need to cast a wide net in initial product evaluations and weigh functionality more heavily than terminology.

"Your future network should be SDN," Burke said. "But focus less on how people are marketing an offering and more on what it can do for you."

Software-driven network scalability

Flexibility and scalability were two problems that Robinson Roca, lead network engineer and cloud architect at a managed network services provider in New York, was trying to solve with a new monitoring platform. But he found the products from established vendors lacking.

"These applications were not scalable, and they were difficult to maintain," Roca said. "It needed a systems person to take care of the server and a network engineer to maintain the software. It's a resource-suck."

He started exploring cloud-based options, eventually landing on Auvik Networks, which offers SaaS that automates network configuration, mapping and monitoring, with versions for both enterprises and managed service providers.

The first network monitoring software he tried required a lot of manual intervention to get it right, but Auvik did not, Roca said. "[The application] was smart enough to know how everything was connected, so it didn't need me to go in and say, 'Connect this device to that device.' It already knew how it was connected, where it was connected and the type of connection that was used."

Auvik requires an on-site software agent that gathers information on customer networks, so they can communicate with its cloud environment, but Roca knew many of the small enterprises he serves would balk at buying and maintaining single-purpose customer premises equipment. As a workaround, he built the agents on virtual servers running on existing on-site Cisco routers -- an example of network virtualization.

"Now I can just sell them the router they need to have anyway and sideload my [network monitoring] application," he said.

Roca said Auvik plans to up the ante further, with capabilities rolled out by the end of 2019 that allow users to push updates to their network equipment directly from the monitoring platform interface.

"I'll be able to make a change ... without having to actually log into the gear," he said. "Or I can give my customer access to make the changes they want without having to know the Cisco 'jibber jabber.'"

Software increasingly is driving network design and management, but network managers have to understand the subtle differences among the terms describing a software-driven network that affect network programmability and automation to reap the benefits of flexibility and responsiveness. Still, the heart of the problem is the same: Know what issue you need to solve before trying to apply software-driven network technology.

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