What is SD-WAN?

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As businesses grow, linking branch offices with headquarters in one larger network becomes necessary. However, traditional Wide Area Network (WAN) technology has several limitations, especially regarding reliability and speed.

SD-WAN addresses these issues, making it an increasingly popular WAN option. 

Also see: SD-WAN is Important for an IoT an AI Future 

What is SD-WAN?

SD-WAN stands for Software-Defined Wide Area Network and refers to a new way of building networks focused on speed, resiliency, automation, security, manageability and ease of use. Traditional routers have limited scalability, meaning they can usually only connect to a few hundred clients simultaneously. And legacy wide area networks are often subject to latency issues due to bottlenecks in their design. 

But with SD-WAN, companies can quickly deploy high-performance WAN services over any network infrastructure—including MPLS, broadband internet or even LTE—which means they can scale rapidly without having to worry about managing multiple vendors or different types of hardware.

How Does SD-WAN Work?

Traditional WAN services are provided using Layer 2 and 3 VPNs to direct traffic to an Internet gateway. SD-WAN uses centralized control to direct WAN traffic to SaaS and IaaS providers securely. 

Unlike traditional routers that simply route packets from one location to another, SD-WAN uses a cloud service with intelligence built into it. The service monitors network conditions across all your sites to route traffic through optimal connections. The service will then dynamically route data between available networks. This means that network failures or congestion can be handled quickly with minimal impact on your organization’s productivity. 

Also see: Cloud is Down: Protecting Your Organization against Outages

What Problems Does SD-WAN Solve?

Network reliability is a big problem in most companies today. A standard WAN connection often sees high latency and packet loss, particularly as you move away from large metro areas where bandwidth is more plentiful. Adding backup or secondary WAN links doesn’t help much when latency becomes an issue. 

So how do you fix it? SD-WAN can solve some of these problems by applying various techniques to relieve congestion on your network without requiring an overhaul of your existing infrastructure. For example, if latency issues affect your users on a particular link, SD-WAN could temporarily shift traffic to another link with less traffic. If one of your links goes down completely, SD-WAN could automatically reroute traffic through another link until repairs are made. 

And, because SD-WAN is software-based, there’s no need for expensive hardware upgrades. SD-WAN also offers automated failover capabilities, so traffic will be routed through a secondary link immediately (without human intervention) if your primary connection fails. 

This automation frees IT staff to focus on other projects rather than being tied up monitoring their networks 24/7. SD-WAN also helps enterprises transition between on-premises data centers and cloud services. 

SD-WAN Architecture

SD-WAN is a software layer that sits between an enterprise’s existing branch routers and its cloud provider, usually functioning as connective tissue between two disparate networks. The technology allows companies to connect multiple branches with various types of links or Internet service providers (ISPs), creating a unified network no matter how many locations are involved. 

To do so, it must automatically determine where data should be sent for optimal performance. This means that even if a user accesses their company’s virtual private network (VPN) from home over their ISP connection, all of their traffic will be routed through whichever link provides optimal speed at any given time. This makes it possible to create one cohesive virtualized network across all sites rather than managing each location separately.

Features of SD-WAN

SD-WAN provides increased flexibility by letting you optimize various features and traffic flows, with or without IT intervention. At their core, SD-WAN solutions are built to work on your existing infrastructure while allowing you to scale as needed. 

Support for Multi-Protocol Label Switching

Also known as MPLS, multi-protocol label switching provides greater control over a business’s WAN because it lets you change from one protocol to another based on what works best at any given time. For example, MPLS gives companies more freedom when setting up their WANs because they can easily adjust how they move data from one location to another, depending on current needs. 


Because SD-WAN lets you take advantage of real-time monitoring and analytics, there’s no need to hire additional staff members to keep an eye on things. That means that even if you don’t have dedicated IT support, there will still be people around who know how to use your network efficiently—because SD-WAN does all that heavy lifting for them. 

Real-Time Traffic Shaping 

SD-WAN provides real-time traffic shaping capabilities, allowing businesses to prioritize different kinds of data. In addition to prioritizing certain types of data, companies can block unwanted content such as malware and phishing attacks before reaching end-users. 

Visibility into Applications

With complete visibility into applications within your organization, you’ll be able to see precisely where bottlenecks exist so that you can solve them quickly and easily without sacrificing performance. This insight benefits companies that rely heavily on bandwidth-heavy applications like video conferencing, VoIP calls, and other cloud services. 

Cloud Connectivity

Businesses can save money and increase overall efficiency by connecting to several different cloud platforms. If a company relies heavily on public clouds for backup purposes, having access to several providers makes it easier to ensure backups run smoothly.

Also see: Improving Workplace Equity with Unified Communications 

SD-WAN Use-Cases

The SD-WAN service helps enterprises maximize productivity by creating resilient WAN networks that enhance application performance in uncertain or unreliable circumstances. This is achieved through intelligent path selection based on dynamic criteria such as cost, latency, bandwidth, jitter and packet loss. This results in a highly reliable network with minimal downtime for critical applications. 

Mobile Offices 

If your employees work remotely but need to be connected to your corporate network at all times, you’ll want to ensure they have a secure connection wherever they go. An SD-WAN solution will help you achieve that by providing them access to your company’s virtual private network (VPN). 

Disaster Recovery 

In an emergency, companies must be able to continue operating without disruption. An SD-WAN solution can help ensure that even if part of your office is destroyed or inaccessible due to flooding or fire, you can still connect with employees who remain in unaffected areas of your building via VPNs. 

Application Performance Optimization 

If your company relies on specific daily operations applications, you’ll want to ensure they’re always available. An SD-WAN solution will help you achieve that by optimizing application performance across your entire network so that no matter where your employees are located, they have fast access to all company resources. 

Visibility into Network Operations and Traffic 

Suppose you need real-time visibility into network operations and traffic statistics. In that case, an SD-WAN solution will provide your company with a comprehensive view of everything happening on your WAN at any given time. 

Improved WAN Resiliency, Availability and Capacity 

When using an SD-WAN solution, your business gains improved WAN resiliency, availability and capacity. This is achieved through intelligent path selection based on dynamic criteria such as cost, latency, bandwidth, jitter and packet loss. 

Automated Provisioning 

With automated provisioning features built into most SD-WAN solutions, companies can easily set up new remote locations within minutes instead of days or weeks, as previously required with traditional private WAN services. 

Security Features 

Many SD-WAN solutions also offer advanced security features, including intrusion prevention systems (IPS), firewalls, malware protection and anti-virus software.

Benefits of SD-WAN

SD-WAN helps businesses connect their locations remotely with more bandwidth, lower latency and greater security than traditional networks that rely on hardware for processing power. Below are some benefits of SD-WAN. 

Reduced OPEX 

Overhead expenses related to your IT operations are called Operational Expenditure or OPEX. This includes data center space, equipment maintenance, etc. Moving to SD-WAN can significantly reduce your annual cost because you don’t need to invest in expensive hardware anymore. Your software only requires a license fee and support, which is much cheaper than buying new networking equipment every few years.

Improved Network Performance 

When using Internet mode, if one link fails, all traffic goes down until another path is found. On the other hand, MPLS provides multi-path routing that enables automatic failover in case one link fails. So even if one link goes down due to failure, other links will still work, thus ensuring continuous connectivity.  

Better Reliability 

SD-WAN can detect and respond to network problems faster and more efficiently than a human operator. It does that by continuously monitoring network health, performance and availability. SD-WAN detects any disruption in the network, and it responds accordingly. For example, if one link goes down due to failure, SD-WAN immediately reroutes traffic through other available paths without manual intervention. This ensures your data always reaches its destination without any loss or delay. 

Also see: Top Enterprise Networking Companies

SD-WAN vs. Traditional WAN

Traditional WANs are expensive, inflexible, and difficult to manage. They require specialized skill sets for configuration, monitoring, troubleshooting, etc. These challenges are compounded when you have remote sites that need access to your corporate network. And because traditional WAN solutions lack visibility into application performance, they’re not well suited for applications with strict quality of service (QoS) requirements. 

By contrast, SD-WAN provides a more straightforward, cost-effective way to connect branch offices with headquarters. SD-WAN can improve security by offering built-in DDoS protection and end-to-end encryption for secure communications between sites. Plus, it allows organizations to dynamically steer traffic based on application needs—ensuring that critical business data isn’t impacted by noncritical activity.

Aminu Abdullahi
Aminu Abdullahi
Aminu Abdullahi is an experienced B2B technology and finance writer and award-winning public speaker. He is the co-author of the e-book, The Ultimate Creativity Playbook, and has written for various publications, including eWEEK, Enterprise Networking Planet, Tech Republic, eSecurity Planet, CIO Insight, Enterprise Storage Forum, IT Business Edge, Webopedia, Software Pundit, and Geekflare.
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