Aryaka, one of a gaggle of startups pursuing software-defined WAN (SD WAN) or "cloud WAN" services, announced Monday that it has closed $16 million in funding, bringing its total funding to $97 million.

The funding was led by Nexus Venture Partners and joined by existing investors Trinity Ventures, InterWest Partners, Mohr Davidow Ventures, and Presidio Ventures.

The nearly $100 million in total funding makes Aryaka one of the most well-funded SD WAN startups. Competitors include Cloudgenix, Pertino, Silver Peak, Talari, and VeloCloud, though all of these companies have a slightly different approach to building out WAN services in the cloud.

Aryaka is building a network-as-a-service (NaaS) for wide-area networks (WAN), providing the user with a virtual network in the cloud. Aryaka has done this by building out a global network of points of presence (PoPs) for WAN services, which it can then deploy to enterprises using standard WAN access hardware and software.

In an NaaS approach, the customer is essentially “renting” a large private network to provide its own WAN services, such as secure VPNs or WAN optimization. The company has dozens of customers in business services and consumer products. (Aryaka was one of the companies featured in the Rayno Report's recent "Future of Cloud WAN" report, which is available here, premium subscription required.)

Aryaka said it will use the money to beef up its sales infrastructure and to invest further in Aryaka ONE, a global, private, secure WAN targeting increased application performance.

The SD WAN movement is about reducing management and deployment headaches for both service providers and customers. In the old WAN model, customers deployed specialized hardware appliances for services such as WAN optimization, applications acceleration, and load balancing. In the SD WAN model, those functions become software in the cloud — or on a NaaS.

Aryaka offers network and application acceleration as a service, using its global network of PoPs. The company says one of the major benefits of its NaaS approach is that customers can bypass the Internet without building their own private network. Some of the other SD WAN startups do use the Internet by applying WAN optimization techniques.

The cloud WAN movement has shaken up the WAN optimization space. Suppliers of WAN optimization appliances, including Riverbed Technology, suffered a drop in revenue growth in the last few years as customers balked at installing specialized appliances for WAN optimization purposes. Riverbed agreed to be taken private by buyout firm Thoma Bravo for $3.6 billion last year.

Riverbed has a deal with Akamai to deliver WAN optimization and application acceleration as a cloud service, reflecting the shifting trends in the space toward the cloud.

The cloud WAN movement is still early in development as the startup field shakes out. Aryaka's healthy history of funding, including this latest round, puts it on the map as one of the more prominent players in the space.