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In today's business environment, traditional approaches to networking are struggling keep up with the pace of digital transformation. Enter SD-WAN.

Short for "software-defined wide-area network," SD-WAN is a specific application of software-defined networking (SDN) technology designed to help organizations streamline the management of IT traffic over a wide-area network (WAN). SD-WAN intelligently and securely routes application traffic beyond conventional WAN locations (i.e., branches, campuses and data centers), extending a network's reach over large geographic distances and connecting remote users far beyond the confines of the physical business.

Today, SD-WAN facilitates the adoption of cloud computing strategies by seamlessly connecting to public, private and hybrid cloud infrastructures, colocation sites and edge resources. It provides an on-ramp to Software as a Service (SaaS) and Infrastructure as a Service (IaaS) services models. Plus, it can enable direct internet access from any location where it's deployed.

There is a reason we use the term "software-defined revolution" when talking about SD-WAN. Just a few years back, conversations with customers about SD-WAN were primarily focused on hardware. Now those conversations center on the role SD-WAN can play in moving customers to modern SDN environments.

How SD-WAN works

SD-WAN involves managing WAN branch routers from a central controller that acts as the "brains" of the network. Network administrators can use this controller to manage thousands of routers from one place, which allows them to build and push out policies to all devices simultaneously. This can greatly simplify IT management.

At the outset, four core features defined SD-WAN solutions:

  1. Transport independence: True flexibility to route applications across any part of the WAN, regardless of the type of transport or circuit in use.
  2. Application visibility: The ability to understand a network's existing capabilities and baseline what applications are running, the number of connected locations and devices, service providers in use, and performance metrics.
  3. Path intelligence: The ability to continuously monitor the performance of network paths and automatically select the optimal path for traffic.
  4. Centralized management via a central controller: With different hardware versions available in the market, today's central controllers can reside in the cloud or on-premises (though on-premises controllers place more of a burden on local IT staff).

In recent years, SD-WAN architecture has evolved to incorporate security and cloud connectivity as key functions. The emergence of SASE (Secure Access Services Edge), plus the integration of security into the SD-WAN network, enhance the security posture for cloud access.

Most recently, SD-WAN vendors have been adding features to enable new and optimized connectivity methods for cloud, including Software as a Service (SaaS) and Infrastructure as a Service (IaaS). This includes providing metrics to understand performance of individual SaaS applications and choosing the optimal paths for performance, or embedding applications in an IaaS cloud and bringing resources directly to the SD-WAN edge.

Finally, recent SD-WAN solutions have enhanced the centralized management functionality to include automation via full-featured APIs to help scale the entire lifecycle of operations, from Day 0 to Day 2.

SD-WAN benefits

Historically, SD-WAN has offered a level of agility simply not possible with traditional WAN solutions. SD-WAN benefits include:

  • Transport independence: Leverage bandwidth across any combination of commodity/broadband internet, 3G/4G/5G, LTE, MPLS, etc., while maintaining security and quality of service (QoS).
  • Flexibility: Enable both cloud-based and on-premises deployments to support your organization's unique policies and processes.
  • Path control: Leverage multiple WAN paths to improve agility, resilience and bandwidth efficiency.
  • Application optimization: Intelligently optimize performance to improve user experience (e.g., via SaaS platforms).
  • Scalability: With cloud-delivered SD-WAN, organizations can increase scalability by lowering their investments in infrastructure and minimizing manual provisioning.
  • Zero-touch deployment: Reduce deployment times with the ability to remotely define and provision new equipment and services at scale.
  • Automation & orchestration: Improve IT productivity and total cost of ownership through the automation of cloud-based management, service orchestration and visibility.
  • Cost optimization: You no longer need to pay for unused bandwidth (once considered your backup link), as all links are leveraged using path optimization capabilities.
  • Security: Integration with SASE platforms provides a full suite of security services, such as secure web gateways (SWGs), cloud access security broker (CASB), and data loss prevention (DLP).
  • Cloud connectivity: More recent SD-WAN solutions feature new methodologies to simplify and accelerate the adoption of cloud computing technology, including direct cloud networking connectivity options and SASE implementations.


At this point, you may be wondering what the difference is between SDN and SD-WAN.

As a refresher, SDN is a way of deploying network infrastructure that simplifies and accelerates operations through automated provisioning, network virtualization, network function virtualization (NFV), service chaining, and centralized policy and configuration management.

The primary difference between SDN and SD-WAN comes down to what each solution is used for. Typically, SDN solutions are adopted by customers who need to manage Local Area Networks (LANs) or by carriers who need to manage core networks. On the other hand, SD-WAN solutions are adopted by customers who want to connect geographically dispersed locations to each other or to a set of remote users.

Whereas SDN is programmable and customizable by the customer or user, SD-WAN is preprogrammed, with updates handled by the vendor (which can mean less work for a network administrator). 

SDN is enabled by NFV within a closed system, while SD-WAN provides application routing that can be virtualized via an existing VPN or run on an SD-WAN appliance.

Generally speaking, SDN solutions are more scalable and can be quickly modified to meet an organization's needs, while SD-WAN solutions tend to me more cost-effective and easier for end users to adopt.

Selecting the right SD-WAN vendor

Choosing the right SD-WAN vendor can accelerate how quickly you're able to achieve the networking capabilities needed to meet your business goals. Before starting your search, you should be aware that not all SD-WAN solutions are comprehensive.

It's important to keep in mind that processes such as market research, training, pilot testing, migration strategy development and integration tasks are all required when implementing an SD-WAN architecture and supporting operations. Without comprehensive network planning and design, it will be extremely difficult for any organization to realize the full benefits of an SD-WAN deployment.

Additionally, the rapid release of new SD-WAN features makes it even harder to keep track of product roadmaps and understand how these new functionalities can help you realize your business goals faster.

If you're looking for somewhere to start, WWT continually evaluates SD-WAN vendors in our Advanced Technology Center (ATC). To keep up with the latest from our experts, make sure to follow the SD-WAN topic on

Getting the most from SD-WAN

SD-WAN is a modern networking and security solution that supports rapid digital transformation by controlling costs, adding agility, boosting performance, and offering organizations management choices. 

An SD-WAN solution should be capable of replacing existing infrastructure, offer the right mix of capabilities and features to meet your business requirements, and integrate well with your existing enterprise architecture.

It's also important to keep in mind that migrating to SD-WAN is more than a plug-and-play exercise. Organizations must invest in a planning phase that involves market research, network and application discovery, a proof of concept or pilot testing, a migration strategy and training.

Here at WWT, we help customers of all sizes plan, select and implement SD-WAN solutions to meet their business requirements and maximize their return on investment.

Learn how our experts can help your company get the most out of SD-WAN.
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