Recent surveys from leading analysts highlight the continuing uptake of software-defined WAN (SD-WAN). Gartner, for example, forecasts SD-WAN to grow at 59 percent CAGR through 2021, while IDC predicts the size of the SD-WAN market to be $8.05B by 2021.

The continuing growth has encouraged a large number of vendors to enter the market, with commentators estimating the supplier base to be between 30 and 40.

That, in turn, is impacting the market for traditional WAN solutions. Gartner forecasts that the branch office router market will decline at a -6.3 percent CAGR through 2020 and the legacy router market will fall by -28.1 percent over the same period.

Despite that, Nemertes Research found that 78 percent of organizations deploying SD-WAN had no plans to completely drop MPLS from their WAN.

Mixed Attitudes to SD-WAN

Gartner’s survey (SD-WAN and its Impact on Traditional Router and MPLS Services Revenue, Worldwide, 2016-2020) found mixed responses among potential buyers.

Many respondents were enthusiastic about increased network availability, reliability and reduced WAN costs. However, some were concerned about the large number of vendors with the risk of instability and potential consolidation. Others cited lack of understanding and hype about SD-WAN performance and reliability.

Overall, SD-WAN is seen as a major contributor to simpler management and configuration of the WAN — replacing routers with a cost-effective, policy-based method of providing reliable, secure branch connectivity.

Innovation Increasing

Recognizing the growth opportunity, vendors are aiming to strengthen their position in the market. Cisco, for example, followed its acquisition of Viptela by announcing plans for deploying Viptela intent-based networking (IBN) technology in the WAN.

The company believes that traditional WAN deployments in the branch network, consisting of multiple, disparate network technologies, lead to inconsistent application experience and user frustration. This complex network structure is also difficult to manage, particularly for sites with no local IT support.

Given the importance of application performance to branch productivity and efficiency, Cisco suggests that the application of IBN technology to the WAN will deliver a strong return on investment.

Cisco’s solution claims to provide two major benefits for WAN management. SD-WAN vAnalytics provides visibility into WAN performance and capacity planning, and enables IT teams to carry out ‘what if’ scenarios before implementing changes. In the longer term, Cisco plans to incorporate automated corrective actions.

The solution also features Cisco Meraki Insight, which provides end-to-end visibility of cloud application performance, simplifying the troubleshooting process.

A Vision for the WAN

Looking ahead, developments like Cisco’s IBN-based solution and the increased adoption of SD-WAN will contribute to the continuing evolution of the WAN.

Commentators believe that WAN evolution — and innovation — will take a number of forms. The development of a unified WAN fabric, for example, will simplify management and support massive scalability. Transport-independent networks will support all types of connectivity and platform-agnostic technologies will allow organizations to deploy physical or virtual infrastructure in any location.

WANs will improve agility by supporting rapid deployment of network services, while analytics and increased visibility will provide actionable insights that minimize downtime and optimize application performance.

In short, the WAN is set to evolve into the highly agile, dynamic network that is essential to digital transformation.