SD-WAN is here to stay. According to International Data Corporation (IDC), worldwide revenue for software-defined wide-area networking (SD-WAN) infrastructure and services is expected to reach $8.05 billion in 2021 – compare that to approximately $500M in 2017.

The rapid development in this market has not gone unnoticed. Today, there are over 60 options for consuming SD-WAN. Two years ago, there were only a dozen or so.

With the rapid growth of this market, and significant customer adoption, there is no shortage of information on what SD-WAN is, what the options are, why it is important, what role connectivity plays, how to implement, and how to manage this next generation technology. This information comes in many forms: vendor marketing, service provider marketing, and articles and blogs by independent analysts and consultants, to name a few.

A wealth of information is valuable, but it can lead to misconceptions about what SD-WAN is, why you should care, and how to get started. All of that can add unnecessary complexity to the evaluation and decision-making process.

Myth #1: SDN and SD-WAN are the same

Software-defined networking (SDN) and SD-WAN share some of the same basic characteristics, and the nomenclature is similar, but the technologies are not the same and have a different purpose.

The Open Networking Foundation defines “software defined” as “the physical separation of the network control plane from the forwarding plane, and where a control plane controls several devices.” Another way to describe this is separating the “brain” from the “muscle”. The brain is the network control plane (policy and configuration) and the muscle is the forwarding plane (data, session, and packet flow). Architecturally, “software defined” enables the network control plane to be programmable, because it’s separated from the underlying infrastructure, and therefore orchestration is possible via policy across a range of common devices.

It is important to note that historically SDN was specific to data center networking. The technology was focused specifically on how network traffic is managed within the confines of the data center network. Several of the top products in the industry are Cisco ACI, VMware NSX, and OpenStack. That said, there are some new SDN technologies that are starting to expand SDN beyond data center networking. Two examples are software-defined LAN (SD-LAN) and intent-based networking (IBN).

Software-defined wide-area networking (SD-WAN) is similar to SDN, but different. SD-WAN employs “software defined" in order to orchestrate the WAN and provide load balancing and application-aware behavior across that infrastructure. SD-WAN is not associated with the data center network; it is specific to WAN communication.

Myth #2: SD-WAN is a replacement for MPLS

This is one of the most common misconceptions about SD-WAN.

Multiprotocol Label Switching (MPLS) is a mechanism for routing network traffic within a communications network. MPLS is typically consumed by an organization via a service provider or telecom provider as a managed service.

SD-WAN is a technology that operates as an overlay and enables WAN traffic to be directed across multiple physical transport connections. Those connections could be broadband, DIA, cellular, satellite or private circuits such as MPLS. One of the key benefits of SD-WAN is the ability to intelligently direct WAN traffic across the most efficient, cost-effective link based on the application’s requirements.

SD-WAN and MPLS is not an either/or discussion. The two are mutually exclusive and the existence of one in a WAN architecture does not necessarily exclude the other. The two can coexist, and in fact, SD-WAN can leverage and complement an existing MPLS network. Being that SD-WAN can be deployed with any type of transport the bigger question is which transport, and the answer to that question hinges on the right balance of Service Level Agreement (SLA) and cost savings. The one exception is the several Network as a Service (NaaS) offerings that provide SD-WAN as part of a range of other networking services as an alternative to traditional managed private connectivity such as MPLS, VPLS, and Metro Ethernet.

SD-WAN is often marketed as a replacement for MPLS because SD-WAN promises high bandwidth and low cost. In reality, however, SD-WAN is so much more than that.

Myth #3: SD-WAN is all about connectivity cost savings

This is closely related to the previous myth.

A lot of use case examples have been put forward touting the savings in telecom connectivity costs using SD-WAN. Some are so compelling that it’s easy to overlook the nuances. Not to mention, other soft-cost savings associated with the time to deploy, the time to perform updates, MACs (moves, adds, and changes), and overall management with SD-WAN can get lost. But they are no less real and shouldn’t be ignored.

More importantly, cost savings is only one benefit of SD-WAN. Other reasons to deploy the technology include the following:

  • User and application performance – SD-WAN offers more efficient utilization of available links and more intelligent routing for on premise and cloud applications resulting in improved user experience and application performance.
  • Operational agility – SD-WAN provides an easier, more effective method of deployment and management. It offers better orchestration and automation and ensures consistent policy across all devices.
  • Enhanced security – SD-WAN enables enhanced security through segmentation and isolation of critical application traffic.

Myth #4: SD-WAN is just the next generation of WAN technology

SD-WAN is not just a simple refresh to WAN technology. It represents a leap forward in WAN architecture in a space that has not seen a substantial change in 10-15 years. For reference, the impact is as great as the impact virtualization has had in the data center.

SD-WAN is about fundamentally changing the way WAN networks are designed, operated, and managed. Historically, the WAN was very static, complex, and disconnected from the priorities of IT. SD-WAN solves all of these problems via centralized orchestration, policy in place of configuration, and advanced visual reporting. Additionally, the WAN can much more effectively support the dynamic needs of cloud, digital, mobility, and IOT initiatives. Having a single solution that increases performance, reduces cost, and increases agility it is clear to see why SD-WAN is one of the hottest technology trends in the market today.

Myth #5: There are only two methods for consuming SD-WAN

A common misunderstanding in the marketplace is that there are only two ways to consume SD-WAN: self-managed or as-a-service from a telecom provider.

But the fact is, there is a third option.

In the self-managed model, as the name suggests, the customer is responsible for everything except the telecom circuits. The customer must select and purchase the SD-WAN product, plan and execute the implementation, and perform ongoing maintenance and management. And they are responsible for providing the skilled resources, either by contracting for them or through training their staff.

Buying SD-WAN from a telecom provider involves contracting with the provider for the services and paying for it as part of the overall WAN cost which typically includes (at least) some of the circuits while the remaining circuits require an additional telecom provider. In this case, the customer has little to no input over which SD-WAN product is implemented, how its implemented, and what product features are available.

The third option is to contract with a managed services provider (MSP). With this option, the customer can choose their preferred SD-WAN vendor and have the MSP plan and execute the implementation specific to the customers requirements. Additionally, the MSP will perform ongoing support and maintenance.

SD-WAN is worthy of consideration for every organization, but getting beyond the myths can be a challenge. For more information, check out or contact your ePlus Account Executive.


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