A leased-line renewal is the perfect moment to rethink your WAN. How SD-WAN works, when it fits (and when it doesn't), and how to migrate in stages.
Why revisit the WAN now
Traditional MPLS-centric WANs were optimized for an era when most traffic flowed to the corporate data center. Now that applications live in the cloud, hairpinning branch traffic through the data center wastes both latency and money.
Per megabit, leased lines cost several times — sometimes tens of times — more than internet circuits. That is why so many companies evaluate SD-WAN at renewal time.
How SD-WAN works
SD-WAN virtually bundles multiple circuits — internet, LTE/5G, existing leased lines — and steers traffic per application. Critical systems ride the high-quality path while SaaS and video break out locally to the internet, all managed by central policy.
Sites are connected over encrypted tunnels (IPsec, WireGuard and the like), so even inexpensive internet circuits carry traffic confidentially.
Where it fits — and where it doesn't
Many sites, cloud-first workloads, pressure on circuit costs — SD-WAN fits these profiles well. Trading systems that need guaranteed millisecond latency, or traffic that regulation confines to private networks, still belong on leased lines.
In practice the answer is usually hybrid: keep the private circuit for core systems and move everything else to SD-WAN. It is not an all-or-nothing choice.
How to migrate
Start with an inventory: circuits, bandwidth and real traffic flows per site. Then cut over low-risk sites first, verify quality, and expand. Convey supports the full journey — from that initial survey through design, build and operations.