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SDN blogs: Will the SD-WAN market gold rush pan out?

How big is the SD-WAN market? One blogger says to take your best guess. And a network engineer argues that the ONF's definition of SDN is "mostly useless."

Software-defined WAN (SD-WAN) startups -- companies that are bringing the concept of software-defined networking (SDN) to the wide area network (WAN) -- are collecting 10s of millions of dollars in venture capital, writes PacketPushers blogger Drew Conry-Murray. But is the escalating SD-WAN gold rush sustainable, or a flash in the pan?

Conry-Murray looked at several reports on SD-WAN -- some of which lumped the nascent technology with WAN optimization. With market projections ranging from $3.2 billion by 2018 to $12.1 billion by 2019, he concludes that the future of the SD-WAN market is still uncertain.

"Everyone in the industry I talk to has a gut feeling that a market exists, because there's a pent-up demand to simplify provisioning, take advantage of multiple connectivity options, get a better handle on actual traffic and drive down costs," he writes. "But gut feelings aren't very satisfying."

He goes on to suggest that by 2019, we may not even consider SD-WAN to be a standalone market category, with providers including SD-WAN capabilities in their infrastructure as a matter of course. Similarly, other analysts have suggested the days of pure-play SDN vendors may be numbered.

What's the correct definition of SDN?

According to the Open Networking Foundation (ONF), SDN is "the physical separation of the network control plane from the forwarding plane, and where a control plane controls several devices."

But network engineer and blogger Ivan Pepelnjak argues that real-world implementations don't fit neatly into the ONF's definition of SDN, which he calls "mostly useless." He argues that the ONF's SDN Architecture 1.0 document takes a more nuanced and accurate approach by clarifying, for example, that an SDN controller can actually delegate some control functions to the data plane. In that case, the decoupling of the control and data planes is not absolute, as "an agent in the data plane is itself exercising control."   

He adds that the definition of SDN has therefore expanded to include anything with a central control element, such as a network management system, which means the term "SDN" is now as vague as "cloud."

Salespeople and NFV

Finally, networking consultant Tom Nolle published a series of blog posts on building the network functions virtualization (NFV) business case, with a recent post considering the perspective of salespeople.

Nolle writes that all of the salespeople who have commented on his NFV blog series -- about 30 of them -- say that the market is growing more slowly than they anticipated, and that their companies are dissatisfied with current sales figures. He points out, however, that users typically adopt new technology more slowly than vendors would like.

Nolle also identifies an important disconnect between buyers and sellers. While the former say they aren't buying NFV because they haven't yet seen a clear business case, the sellers blame buyers for their wariness of new technology and the associated risks.

Ultimately, Nolle concludes that NFV is still "a technology in search of a justification." In other words, salespeople need to identify buyers' goals and push NFV benefits that can meet those specific objectives.

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