SD-WAN vs MPLS.
They serve different jobs.
SD-WAN and MPLS both connect your offices, but they carry traffic differently, cost different amounts to run and suit different applications and compliance needs.
A business with several sites has to join them somehow. SD-WAN and MPLS are the two names that come up in that conversation. They're not interchangeable. MPLS is a private path on a carrier's network, so traffic between offices never uses the public internet. SD-WAN is software that sits over the internet links you already have, or can add, and chooses a route for each application.
The right answer depends on what you run, not on which name is currently fashionable. Cloud systems such as Microsoft 365 and Azure prefer a local internet breakout. Applications that need tightly controlled latency, or traffic that must stay off the public internet, still favour MPLS. If you already have MPLS, the real job is deciding what still needs a private path and what can move.
| Factor | SD-WAN | MPLS |
|---|---|---|
| How it works | Software overlay that uses leased lines, broadband or mobile links and picks a path for each application based on live conditions. | A private carrier network. Traffic between your sites stays on that network and never crosses the public internet. |
| What you pay | You can mix cheaper internet circuits with leased lines, so you only pay for a private path where the traffic actually needs one. | Dedicated private circuits cost more to provision and keep, and every site usually needs the same class of link. |
| Cloud access | Each site can reach Microsoft 365, Azure and other cloud services directly, without sending that traffic back through head office first. | Branch traffic often returns to a central site before it can reach the internet, which adds delay for cloud applications. |
| Latency and jitter | Performance follows the underlying internet circuits. You can prioritise applications, but the carrier doesn't guarantee latency the way MPLS does. | Carriers can commit to latency, jitter and packet loss on the private path, which suits real-time systems that suffer when delay varies. |
| Traffic isolation | Traffic between sites is encrypted as it travels over public or mixed links. Security still depends on firewalls, identity and endpoint controls. | Traffic never leaves the carrier's private network, so isolation from the public internet is built in rather than added as an overlay. |
| Adding new sites | New offices can come online on internet circuits in days, and policy changes apply from a central controller rather than a carrier change request. | Provisioning a private circuit often takes weeks, and changing bandwidth or adding a site means waiting on the carrier's order process. |
When SD-WAN is the right call
- You rely on Microsoft 365, Azure or other cloud services and need each office to reach them without a detour.
- You're opening sites, closing them or changing bandwidth and cannot wait weeks for a private circuit.
- You want internet circuits at most sites, with a private path reserved for the traffic that actually needs one.
When MPLS is the right call
- Compliance or internal policy requires traffic between sites to stay off the public internet.
- You run real-time systems that need a committed latency figure the internet cannot reliably give.
- Legacy applications at your sites degrade when jitter or packet loss rises, and a private path keeps them stable.
What we’d recommend
For most UK businesses running Microsoft 365 and other cloud systems, we'd run SD-WAN as the overlay and use internet circuits at each site. We would keep MPLS where a private path is required, or where an application cannot tolerate variable delay. If you are already on MPLS, we don't rip it out for the sake of it. A mix is common: SD-WAN across the estate, MPLS only for the flows that need it. Wanzo can provide either, so we start from your sites and applications, plus any compliance rules, then recommend the mix. The monthly service covers design, deployment and 24/7 monitoring, with a four-hour response commitment.
Questions people ask
Do I still need MPLS if I move to SD-WAN?
Not always. Many businesses can move day-to-day cloud and office traffic onto SD-WAN over leased lines or broadband, and drop MPLS at sites that do not need a private path. You would still keep MPLS if compliance says traffic must stay off the public internet, or if an application needs a committed latency figure. Wanzo looks at the sites, the applications and any existing contracts before recommending a cutover, a hybrid or leaving MPLS in place. We can manage either on a monthly retainer.
Which is more secure, SD-WAN or MPLS?
They secure traffic in different ways, so the better choice depends on the requirement. MPLS keeps site-to-site traffic on a private carrier network, which is why it still suits firms that must keep that traffic off the public internet. SD-WAN encrypts traffic as it travels over internet or mixed links, and it needs firewalls, identity and endpoint controls around it. Encryption isn't the same as isolation. Wanzo can run cybersecurity alongside either design, including Fortinet, Microsoft and Cisco technology, so the WAN is not treated as a separate security problem.
Is SD-WAN cheaper than MPLS?
Usually, because SD-WAN can use business internet at sites that do not need a private circuit. MPLS charges for dedicated capacity on a carrier network, so the monthly cost stays high even at smaller offices. That doesn't mean SD-WAN is always the cheaper service. You still pay for the overlay, the underlying circuits, security and management. A hybrid can cut spend by moving cloud traffic off MPLS while leaving private paths in place. Wanzo prices the mix against your current contracts rather than assuming every site needs the same link.
Can you run SD-WAN and MPLS together?
Yes. A hybrid WAN is a normal design, not a compromise. SD-WAN sits as the overlay and can send cloud and general office traffic over internet circuits, while MPLS carries the flows that need isolation or a committed delay. Existing MPLS contracts can run down rather than being cancelled early. Wanzo designs the split around applications and site criticality, then monitors both paths. That is often the practical route for a business that is already on MPLS and moving more work into Microsoft 365 or Azure.
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