How SD-WAN Is Simplifying and Accelerating Multi-Cloud Adoption


While MPLS was highly reliable, it wasn’t scalable due to its hardware-centric design. Upgrading to the multi-cloud approach meant more equipment and labor-intensive upgrade and configuration processes. SD-WAN leverages network function virtualization technologies that allow network admins to deploy routing and security policies using a central controller to the SD-WAN devices at each corresponding site.

If we refer to an enterprise as a universe, it wasn’t too long ago when the data center was at the center. Like a solar system, defined geographical WAN sites orbited around the data center hub.  Everything was interconnected through a WAN made up of a multiprotocol label switching (MPLS) system. Each thing was routed to the data center by default through a static pipeline, prioritized by QoS policies. The applications were hosted on on-premise servers to handle most of the workload within the enterprise itself. The internet traffic was also handled in a similar way.  If a user in Omaha needed to access the internet for something, traffic was backhauled to the data center in Atlanta, which hosted the exclusive internet connection. While it may seem absurd to backhaul a user’s webmail session thousands of miles over one’s WAN before routing it to the internet, it actually made sense back then. It was the problem back then.

While the data center may still reside centrally in architecture, from a functionality perspective, it is no longer the focal point center it once was. The great migration to cloud servers changed all of that, and the enterprise has become more extensive as a result. The cloud is now at center stage. There’s not just one cloud anymore, but multiple clouds that support virtual server infrastructures, SaaS applications, data, and backups. These cloud-based resources orbit the physical sites, serving as depositories for the users that require access to them. The web browser is now the universal application for this multi-cloud universe, and the internet router is now the primary gateway for workloads traffic.  

While cloud migrations have been a core element of digital transformation strategies, not everything has been lifted and shifted to the cloud. A lot of data collection and compute resources have moved to the outer edges to be close to mission-critical processes and customers alike. The very idea of edge computing seems completely contrary to the hub and spoke architectures that MPLS supports. This collection of multiple clouds and edge computing sites collectively create a distributive plane that can potentially increase an organization’s resilience, availability, and responsiveness. That potentiality is dependent on whether the WAN is optimized for the new modern enterprise or not. 

Learn More: Top IT Tools and Best Practices to Mitigate Cloud Data Migration Risks

Take the Fastest Route

Unless we are partaking in a relaxing Sunday drive, drivers use digital smartphone technology today to help them navigate the fastest route to get to their destinations. SD-WAN takes that same approach. Case in point, the email server is no longer situated at the data center for so many companies today, so why is O365 traffic still being routed there? Similarly, a user at a branch location should no longer be routed to the data center to access the SaaS application their job role depends on. Instead, the branch office needs to be connected to the internet in the same way corporate is. 

Many applications are latency sensitive whether they reside on a server on a different floor of the office building or in a cloud data center in another country. Users need to be able to have a local-like experience when interacting with a SaaS application. By connecting and interacting with a cloud-based application using the shortest route possible, application performance is optimized as well as the user experience. In a digital world, speed is of the essence.    

Dealing With Complexity

Of course, not all applications and services can be migrated to the cloud. While MPLS sent everything to the enterprise hub, not all traffic is internet bound either. Many organizations are saddled with custom legacy ERP applications that must still be hosted locally due to the exorbitant costs of upgrading to the cloud. Many a CFO wants to continue to utilize existing local infrastructures due to depreciation tables that have not yet been exhausted. In these cases, the conventional MPLS must still be utilized. Now factor in remote work strategies in which users must access on-premise resources using VPN and other remote access technologies, and the complexity of everything becomes quickly evident. 

The Growth of SD-WAN

First, software-defined servers, then the network and storage, until all three facets of the data center were software defined. The remaining area is the WAN itself. The software-defined WAN has now become a priority for IT enterprises today for several reasons. 

  • Just as the practice of overprovisioning data center resources severely impacted the ROI of a traditional server, organizations have realized that they can no longer afford to oversubscribe and pay for anticipated peak capacity. 
  • Organizations need a WAN that is just as adaptive as the hybrid cloud architectures their IT teams have created using private and public cloud resources. Internal IT now realizes that the enterprise at large is only as agile as its most nimble component, and the WAN has been a restrictive culprit that has been ignored too long. 
  • Company leaders have also recognized that the front-line employees closest to their customers must have the same network performance as those far away in the data center. 

Having recognized the importance of rearchitecting the WAN itself, demand is growing for SD-WAN solutions, and companies are dramatically increasing resource allocations towards this technology. According to an August 2020 reportOpens a new window , the global Software-Defined Wide Area Network (SD-WAN) market size is expected to grow from USD 1.9 billion in 2020 to USD 8.4 billion by 2025, at a Compound Annual Growth Rate (CAGR) of 34.5 percent. 

Learn More: Tap Into the True Power of SASE With SD-WAN 

How SD-WAN Works

While MPLS was highly reliable, it wasn’t scalable due to its hardware-centric design. Upgrading meant more equipment and labor-intensive upgrade and configuration processes. SD-WAN leverages network function virtualization technologies that allow network admins to deploy routing and security policies using a central controller to the SD-WAN devices at each corresponding site. By using policies and intelligence-driven traffic analysis, the SD devices can route traffic by destination and prioritization. Bandwidth links can be added or aggregated to form congruent pipelines to stream traffic through its appropriate avenue when needed. SD-WAN also adds greater resiliency. If a local internet connection goes down, SaaS and web traffic can be routed to another connected internet site. 

With MPLS, there was no need for security as all traffic was contained within the perimeter. With multiple internet-connected avenues present throughout in areas that are not protected by the primary network firewall, SD-WAN systems must also secure and defend the very traffic it is steering to its appropriate destinations. This is done through next-generation firewalls that can communicate and work in sync with the main data center firewall. Through this coordinated system, admins can gain visibility into ingress and egress traffic types within each site location and issue necessary security policies.  


While MPLS indeed served its purpose at one time, it is a system that is simply inadequate today to deal with the variety of workloads that traverse the multiple clouds contained within today’s complex infrastructure. SD-WAN is about so many things: routing optimization, resiliency, agility, and security. It is a solution that has come of age to satisfy the demands of today’s modern networks.

Do you think that SD-WAN can make multi-cloud migration easier and less complicated? Comment below or let us know on LinkedInOpens a new window , TwitterOpens a new window , or FacebookOpens a new window . We’d love to hear from you.