New deployment data shows SD-WAN has crossed the mainstream threshold. IT teams that delayed migration are now facing a performance and cost penalty that compounds every quarter.
Key Takeaways
SD-WAN has been described as the future of enterprise networking for the better part of a decade, but 2025 was the year that description became past tense. New deployment data from Gartner's annual network transformation survey shows the technology grew 47% year-over-year, crossing the threshold that analysts use to define mainstream adoption. For the majority of enterprise organisations, SD-WAN is now the standard. For those still operating on legacy MPLS circuits, it is increasingly a competitive liability that shows up in application performance metrics, IT cost structures, and cloud connectivity quality.
The data does not flatter late movers. Enterprises still running primarily MPLS-based WAN architectures are paying 3.2 times more per Mbps than organisations that have completed SD-WAN migrations. They are also reporting mean application performance scores 38% lower, a gap driven by the fundamental architectural mismatch between MPLS, which was designed to optimise traffic between corporate data centres, and the cloud-first application portfolios that now dominate enterprise software stacks. When the majority of application traffic no longer terminates at a corporate data centre, a WAN architecture built to serve that model creates latency, cost, and availability problems that cannot be resolved through incremental optimisation of the existing infrastructure.
The cost-per-Mbps differential is the most straightforward element of the performance gap, but it is not the most operationally significant. MPLS carriers are responding to declining enterprise demand by reducing investment in their MPLS infrastructure and, in several documented cases, actively sunsetting capacity in lower-density markets. This is producing a counterintuitive pricing dynamic: as demand falls and the remaining customers are disproportionately those with limited alternatives, MPLS renewal pricing has been rising at an average of 8 to 12% annually in the most recent contract cycle, even as internet bandwidth costs continue to decline. Organisations approaching MPLS contract renewals are discovering that the status quo is not a neutral choice. It is an actively worsening one both in cost and in the trajectory of carrier investment.
Application performance improvements post-migration are substantial and well-documented. The survey data shows that organisations completing SD-WAN migrations report an average 62% improvement in cloud application response times, driven primarily by the elimination of backhauling. Under legacy MPLS architecture, cloud application traffic from branch offices typically travels to a centralised hub location before being routed to the internet. This design made sense when corporate data centres were the primary traffic destination but creates unnecessary latency for SaaS and IaaS workloads. Direct cloud breakout, a standard capability of SD-WAN platforms, eliminates this routing inefficiency entirely and routes branch office traffic directly to the nearest cloud provider point of presence, reducing round-trip latency by 45 to 70% depending on geography.
Business resilience improvements are equally significant. Legacy MPLS circuits are single-path connections with SLA-governed failover times that typically range from two to four hours for major circuit failures. SD-WAN platforms manage multiple active paths simultaneously, including broadband internet, LTE, and satellite links, and execute automatic failover in under one second when a primary path degrades. The survey data shows that enterprises post-migration report 99.97% WAN availability on average, compared with 99.7% on legacy MPLS architectures. In hours of annual downtime, that gap represents the difference between approximately 16 minutes and 26 hours. For organisations running real-time financial transactions, manufacturing control systems, or customer-facing services, the reliability improvement alone has justified the migration cost.
"The organisations that are still on MPLS are not just paying more. They are experiencing the compounding effects of running a WAN architecture that was not designed for cloud-first application portfolios. Every quarter they delay, the gap between their network performance and their competitors' gets wider."
Tanya Okonkwo, VP Network Strategy, Gartner
The survey data surfaces a clear cluster of practices that distinguish successful SD-WAN migrations from troubled ones. The first is a phased, branch-by-branch rollout approach rather than an attempt to migrate the entire WAN simultaneously. Organisations that attempted parallel site migrations or tried to compress the migration timeline to reduce overlap costs reported post-migration incident rates three times higher than those that executed methodical, site-by-site transitions with adequate stabilisation periods between phases. The additional timeline cost of the phased approach is typically recouped within the first six months of completed operation through the reduction in post-migration remediation work.
The change management dimension is the least technically complex but frequently the most organisationally difficult element of a successful migration. WAN operations teams whose skills are built on MPLS, BGP routing, and traditional circuit management face a genuine competency transition when moving to SD-WAN platforms, which are configured through centralised orchestration interfaces and rely on fundamentally different operational models. Organisations that invested in structured reskilling programs for these teams before migration completion reported 67% fewer operational issues in the 90 days post-cutover than those that assumed existing staff would adapt independently. This is not a trivial investment: a comprehensive SD-WAN operations training program for a team of six to eight network engineers typically requires 8 to 12 weeks of structured learning. Organisations that treated it as optional consistently paid.
Pre-migration application performance baselining is the third differentiating practice, and it serves two purposes. First, it creates the measurement baseline needed to quantify post-migration improvements for internal ROI reporting, which matters for sustaining budget and leadership support through a multi-phase migration program. Second, and more practically, it identifies application performance problems that exist prior to migration and might otherwise be attributed to the SD-WAN deployment. Organisations that entered migration with no performance baseline frequently found themselves spending post-migration engineering time investigating performance issues that predated the migration entirely. Vendor selection is also meaningful: survey data shows that migrations led by vendors with documented professional services capabilities in change management, rather than purely technical implementation, correlated with significantly higher satisfaction scores at 12 months.
The road ahead for SD-WAN is defined by its convergence with security service edge capabilities under the SASE framework. 61% of new SD-WAN deployments in 2025 included integrated SSE components, reflecting enterprise recognition that network architecture and security architecture can no longer be designed in isolation. For organisations still in the planning stages of SD-WAN migration, this convergence is both an opportunity and a planning consideration: the vendor selection decision made today will determine the available SASE integration path for the next five to seven years. IT leaders evaluating SD-WAN platforms should treat SSE integration capability and the vendor's SASE roadmap as first-order selection criteria rather than secondary considerations evaluated after the network decision has already been made.
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