SD-What? A Quick Explanation of What SD-WAN Is and How It’s Deployed

By Brianna BoudreauJul 12, 2023


Corporate traffic patterns continue to change. And static, single technology transport networks designed to secure internal corporate communications no longer meet network requirements.

Today they are being replaced by dynamic, hybrid, application-aware networks.

These new WANs are intelligent at the edge. They are able to categorize data and route it over a variety of transport types based on policy or application performance requirements. And they ensure a high-quality, secure experience to users regardless of their physical location, access device, or application location.

One innovation assisting WAN managers in deploying hybrid networks—while also ensuring the security and performance of their network—is SD-WAN.

SD-WAN Overview

Software-Defined Wide Area Networking (SD-WAN) is a service that enables enterprises to dynamically route traffic across a hybrid WAN based on current network status.

Replacing traditional branch routers with appliances that assess and utilize different transport technologies, it allows enterprises to route large portions of their traffic over cost-effective services such as dedicated internet access or broadband, while placing voice, video, or other QoS-sensitive traffic, such as voice or video over private MPLS links as needed.

Enterprises can pre-configure performance criteria for different applications in their centralized controller, and path decisions are based upon which links meet these application performance metrics depending on packet loss, latency, and jitter.

Deployment Models

Customers can deploy SD-WAN in one of two ways—as a software suite, or as a combination of hardware and software supplied by the vendor.

Customers can deploy SD-WAN in one of two ways—as a software suite, or as a combination of hardware and software supplied by the vendor.

With hardware or equipment-based services, SD-WAN devices replace or augment the existing customer premises equipment (CPE) at each branch site. The SD-WAN devices connect to centralized or cloud-based controllers that manage application policies and security features. This vendor-supplied CPE often includes support and a service level agreement to address damage or failure.

Some suppliers embrace proprietary hardware. Others supply branded commodity hardware (a “gray box” approach). Several support software installation on generic hardware (a “white box” approach). However, according to vendors profiled in our WAN Manager Survey, most implementations do not use this option.

In a software-based solution, customers download software onto the existing WAN infrastructure at the branch site, using network access to communicate with the centralized controller.

Software-based approaches can be cloud or local software run on dedicated hardware, generic hardware, or as a virtual function. Cloud simplifies processing but introduces a remote connection and latency. Local processing reduces latency, but introduces maintenance—and hardware.

Regardless of which option customers opt for, the software on the system captures most of the intelligence in the solution.

Ready to take your SD-WAN knowledge to the next level?

TeleGeography's Cloud and WAN Research Service has been cataloging the vendor landscape since SD-WAN came on the scene. We extracted detailed vendor profiles from this service to create our SD-WAN Guide.

You'll also find additional insight on SD-WAN trends from our arsenal of research included in this offering. Grab your free copy over here.

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Brianna Boudreau

Brianna Boudreau

Senior Research Manager Brianna Boudreau joined TeleGeography in 2008. She specializes in pricing and market analysis for wholesale and enterprise network services with a regional focus on Asia and Oceania. While at TeleGeography, Brianna has helped develop and launch several new lines of research, including our Cloud and WAN Research Service.

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