Introducing a Software-Defined WAN

The software-defined wide area network (SD-WAN) is a specific application of software-defined networking (SDN) technology applied to WAN connections, which are used to connect enterprise networks – including branch offices and data centers – over large geographic distances.
A WAN might be used, for example, to connect branch offices to a central corporate network, or to connect data centers separated by distance. In the past, these WAN connections often used technology that required special proprietary hardware. The SD-WAN movement seeks to move more of the network control is moved into the “cloud,” using a software approach.

SD-WAN Business Drivers

Enterprise customers are demanding more flexible, open, and cloud-based WAN technologies, rather than installing proprietary or specialized WAN technology that often involve expensive, fixed circuits, or proprietary hardware.
Many of the new SD-WAN offerings, for example, can be used to improve and secure Internet connectivity, making it more competitive with more expensive legacy WAN technologies such as T-1 or MPLS. In some cases, SD-WAN technology uses Internet broadband connections to replace more expensive solutions. Virtualization technology can apply security and virtual private networking (VPN) technology to broadband Internet connections, making them more secure.
SD-WAN also has the advantage of removing potentially expensive routing hardware by provisioning connectivity and services via the cloud. Emerging SD-WAN technology can also be more flexible. For example, because SD-WAN connectivity can be controlled through cloud software, a customer might be able to scale up or “burst” connectivity during times of peak demand.

Customer Focus: Cost, Reliability, Security

The main goal of SD-WAN technology is to deliver a business-class, secure, and simple cloud-enabled WAN connection with as much open and software-based technology as possible. This can be used to deliver basic WAN connectivity, or it can be used for premium business services such as VPN, WAN optimization, and applications delivery control (ADC).

Many new startups are going after the potential in the SD-WAN market, which is likely billions of dollars. Many of these startups have slightly different approaches to the market. For example, Silver Peak has focused on accelerating Software-as-a-Service (SaaS) applications in the cloud, Pertino and VeloCloud are going after branch-office connectivity using SD-WAN, and Aryaka has built a global network so that companies can use WAN as a Network-as-a-Service (NaaS). More than $360 million has been invested in SD-WAN startups, according to Rayno Report research.
Incumbent WAN technology vendors such as Cisco and Riverbed, which make specialized appliances for WAN connectivity, are now focusing more on cloud-based WAN offerings in response to this new trend.

Expect the trend to accelerate over the next few years. What started as a solution for branch-office and data-center WAN connectivity requiring less proprietary equipment appears to be expanding into a wide range of SD-WAN offerings and technologies including VPN, security, WAN optimization, NaaS, and application policy control.