Software-defined WAN was one of the IT areas most affected by the COVID-19 pandemic. Before the wave of lockdowns and work-from-home orders hit enterprises in early 2020, 61% of enterprises said they had begun an SD-WAN rollout. By the second half of 2021, Nemertes Research found that only 36% of enterprises surveyed had deployed or were in the process of deploying SD-WAN.
The pandemic halted deployments that had just begun. While some organizations have resumed their plans, most SD-WAN plans are still on pause. Technology shifts and the rise of persistent hybrid work have also complicated the network environment to the point where some organizations with fully implemented SD-WAN canceled their services.
As glimmers of a post-pandemic world emerge, network professionals should pay attention to the following four SD-WAN trends:
- SD-WAN as a service
- SD-WAN and secure remote access
- AI in SD-WAN
- SD-WAN and wireless WAN (WWAN)
1. SD-WAN as a service
Early SD-WAN adopters, beset by hard-to-solve WAN problems, deployed DIY SD-WAN. This approach worked well to improve service delivery and reduce management burdens. Successive waves of organizations with fewer problems followed DIY SD-WAN pioneers with rapidly evolving and improving products.
Eventually, enterprises with outsourced WANs began to demand the same improvements to their services, as well as some new freedom to mix and match connectivity. Service providers began to see higher profit margins gained from easier management.
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SD-WAN migration also looked like a logical place for some IT shops to flip the outsourcing switch and leave the WAN business entirely. Managed SD-WAN deployments rose rapidly over the course of three years, accounting for fewer than 8% of deployments in 2017 and rising to nearly 50% by 2020.
Essentially, every managed network service provider brought forward at least one -- and often several -- SD-WAN options. Offerings ranged from managed deployments of DIY technology to carrier-specific, network-based portfolios built around the carrier's own network infrastructure and services.
The end goal of a managed WAN is a network as a service (NaaS) option. Most NaaS providers have incorporated SD-WAN into their offerings now. Over the last couple of years, NaaS providers have revamped their offerings to deliver the main features of an SD-WAN service.
Some capabilities of SD-WAN as a service that NaaS vendors include are redundancy and connectivity choices, policy-driven route optimization and traffic prioritization. Providers had already baked in several SD-WAN-style management, optimization and redundancy features in the middle-mile segments of their architectures, so they only needed to extend the capabilities.
In the larger ongoing shift to anything-as-a-service purchasing, expect to see the appetite for managed SD-WAN drive broader adoption -- both by vertical and by company size -- of NaaS offerings that are now SD-WAN as a service.
2. SD-WAN and secure remote access
SD-WAN functionality relates to the hot market category of Secure Access Service Edge (SASE). During the pandemic, some SD-WAN providers pushed to put SD-WAN endpoints in homes as either physical appliances or software clients.
Some secure remote access providers also offer options in a cloud-like model. Instead of enterprises managing several VPN appliances at data centers to enable secure remote access to services, they would buy the secure connectivity as a service.
Users would connect to the nearest point of presence (PoP) and communicate from there to the data center PoP or cloud provider PoP. Communication would occur across a secured, private middle mile.
Two trends will become more visible in the coming year: combining SD-WAN and secure remote access technology, and replacing SD-WAN with secure remote access.
SD-WAN with secure remote access
On one hand, SD-WAN and secure remote access could come together, SASE-style, with increasing frequency. For example, SD-WAN clients could provide a secure connection to the nearest company site, via its SD-WAN endpoint, and continue to internal resources. Or, a client could connect to a virtual endpoint in a cloud environment and connect to resources there.
Another option is for the client to connect to a SaaS provider PoP or a cloud access security broker. The SD-WAN provides a mechanism to control and monitor traffic, as well as a way to connect remote users to internal and external services.
Secure remote access replaces SD-WAN
On the other hand, many companies might realize the evolution of their service environment from all in-house to mostly or nearly all in the cloud has made their WAN of questionable value. Traditional inside-to-inside traffic now only accounts for about a quarter of a typical WAN's traffic. Organizations could start to question why they would dedicate an expensive network to carrying small and decreasing amounts of traffic and go through gymnastics to manage the data packets coming from or heading outside.
So, another SD-WAN trend is secure remote access entirely replacing a traditional WAN or SD-WAN. Secure remote access without the headaches of a legacy VPN -- whether using a service edge or a software-defined perimeter product running across the public internet -- could meet an increasing number of worker and company needs.
3. AI in SD-WAN
AI is coming to SD-WAN -- or, at least, to SD-WAN marketing materials -- with full force. Expect to see AI-infused SD-WAN offerings both from service providers and vendors. In addition to optimizing traffic path selection, AI could provide better policy definitions, troubleshooting assistance, smarter performance and security monitoring.
The promise, stated or implied, is that AI applications simplify network management for users and managers, compared to previous software designs that governed these functions. Network professionals have to judge that for themselves, product by product.
4. SD-WAN and WWAN
Expect to see huge increases in the use of wireless links for last-mile connectivity within an SD-WAN.
Thanks to SD-WAN, 4G and 5G services are finally coming into their own. Some drivers for WWAN and SD-WAN include the following:
- implementing path diversity with the same carrier used for wired links;
- creating carrier diversity;
- replacing aging and poorly maintained copper cabled plants; and
- avoiding the cost of having good links pulled to a new site.
In situations where WWAN isn't the only form of connectivity, SD-WAN enables policy-based control of how to use the WWAN service. In situations where only WWAN exists, SD-WAN can balance traffic across multiple providers, move traffic from an overloaded service to a less loaded one and perform traffic conditioning to improve quality of service.
In 2023, implementing WWAN with SD-WAN should become easier, at least in 5G areas.
Editor's note: This article was updated to improve the reader experience.