TL;DR — MPLS still delivers rock-solid private performance — at premium per-site cost and with cloud traffic forced through awkward detours. SD-WAN over dedicated internet matches the performance for most workloads, handles cloud natively, adds sub-second failover, and typically cuts per-site spend enough to fund bandwidth upgrades. Most multi-site businesses should migrate; a few latency-critical links deserve to stay private.
Why this debate exists
For two decades, MPLS was the answer to "how do we connect offices reliably": a carrier-run private network with class-of-service guarantees. It worked — and it billed like it. Then work moved to the cloud, and MPLS's hub-and-spoke design started forcing Microsoft 365 traffic from your Brooklyn office through your Manhattan data center just to reach the internet. Expensive and slow is a bad combination.
What SD-WAN actually changes
SD-WAN is an intelligent overlay across whatever circuits each site has — dedicated fiber, broadband, 5G. It measures every path continuously (latency, jitter, loss), steers each application over the best one in real time, fails over in under a second, and sends cloud-bound traffic directly to the cloud instead of hairpinning through headquarters. Policy lives in one dashboard and deploys everywhere at once.
Head to head
- Reliability: MPLS is engineered-reliable on one path; SD-WAN is resilient across two — a cut circuit is a non-event rather than an outage.
- Performance: MPLS guarantees via CoS; SD-WAN over DIA achieves comparable application performance for the vast majority of workloads.
- Cloud traffic: MPLS detours it; SD-WAN breaks out locally. If your apps live in SaaS, this alone decides it.
- Cost: SD-WAN's per-site economics are meaningfully lower — most clients fund faster circuits with the savings.
- Agility: new MPLS sites take carrier lead times; SD-WAN sites turn up the day the circuit is live with a pre-configured box.
- Where MPLS/private transport still wins: ultra-latency-sensitive flows — market data, real-time media, storage sync — deserve private Ethernet or wavelengths. Verdict: hybrid, not dogma.
The migration that doesn't break anything
- Inventory reality: circuits, MPLS contract end-dates, per-app traffic patterns.
- Design diverse circuits per site: DIA primary, genuinely separate backup (different carrier or path).
- Run SD-WAN alongside MPLS — overlay first, observe, tune policy with zero risk.
- Cut over site by site, keeping any latency-critical links on private transport.
- Retire MPLS at renewal, not before — exit fees eat savings.
The honest bottom line
If you're multi-site and cloud-first, SD-WAN over dedicated internet is the modern default: comparable performance, native cloud handling, real failover, lower cost. Keep private transport where physics demands it. We design both — and price the whole build across carriers, free: text 347-870-0965 with your site list.
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