Skip to content


As SD-WAN Technology Evolves, So Must Its Definition

We recently issued a white paper on SD-WAN adoption, which included analysis of data from a survey of 300 IT decision-makers. The paper, released in partnership with Bank Street, has generated a lot of interesting feedback from a diverse group of readers. While there was general agreement on the data and conclusions that SD-WAN is more evolutionary than revolutionary, there was some question regarding the definition of SD-WAN itself.

In the paper, we defined SD-WAN as a networking technology that allows for a separation of the control layer from the transport layer, thus enabling a centralized, user-friendly approach to network management regardless of the underlying access type. According to our definition, SD-WAN can be deployed over any type of access, whether that is MPLS, wireline internet, cellular internet, or some other type of access. This is a broader definition of SD-WAN than what is often used by other publications and organizations, some of which believe an enterprise network can only be called an SD-WAN network if it has an SD-WAN router deployed over only internet circuits.

This is less an issue of semantics, and more about how different people can define technologies differently – especially early in any technology’s lifecycle. Early definitions touted SD-WAN as an internet-only product, but our paper clearly concluded that definition must evolve:

  • Our research showed that SD-WAN, to date, has most frequently been deployed in a “Hybrid” or “Overlay” manner, where MPLS is either one or the only access type for SD-WAN. We found only 26% of all SD-WAN adopters have deployed SD-WAN using only internet circuits. This runs counter to the common wisdom at the time SD-WAN was launched that it would lead to enterprises removing MPLS from their enterprise networks.


  • We also found this “Hybrid” or “Overlay” approach has staying power. Of those that currently adopt a “Hybrid” or “Overlay” approach to SD-WAN, only 24% want to switch to an SD-WAN model that uses internet circuits exclusively.

We think this ability to enable and propagate hybrid access could become even more important in the future, as COVID-19 changes everything about how we live, work, and communicate.

We conducted our last SD-WAN survey late last year, before the COVID-19 pandemic. In an April article, Altman Solon Partner Josh Zaretsky laid out his forecast that 20 million Americas will continue to Work from Home (WFH) after the COVID-19 social distancing restrictions have subsided. Many large technology companies have since announced that WFH will be a permanent option for a portion of their employees, bring closer to reality our prediction that our homes will increasingly start being considered a remote “branch” of a modern enterprise, rather than just where we live.

This new definition of a modern enterprise will force SD-WAN to evolve even more, and quickly. We can envision a future where corporate networks are using an increased amount of SD-WAN over cellular technologies – partly accelerated by the COVID-19 impact on working from home. For some home offices, having routers with SD-WAN functionality across their fixed home internet access and LTE/5G wireless access will be an effective way to maximize the value of their subscriptions and manage traffic across work video conference meetings, remote schooling, gaming, and other competing family demands. Additionally, other cellular/wireless use cases can also drive SD-WAN over cellular adoption (e.g., remote work sites, private wireless networks, IoT). This means that enterprise networks, already hybrid, will became even more so, with cellular access joining wired broadband and MPLS as key components of the future of networking.

This fall, we will be conducting a new survey of IT decision-makers to see how the nation’s SD-WAN buying and deployment strategies have changed. We look forward to sharing those findings then.

In the meantime, we have made some minor labeling and wording edits to our white paper to clarify the definition of SD-WAN. We appreciate the feedback we have received thus far, as it makes our work better.

Leadership & Oversight

Mat Grudzien


This research has been conducted by Altman Vilandrie & Company in June 2020.