If you connect multiple sites, you've probably weighed MPLS against SD-WAN. Both create a private wide-area network, but they take very different approaches. Here's how they compare and how to choose.
What each one is
MPLS (Multiprotocol Label Switching) is a private, carrier-managed network that routes traffic over dedicated paths. It's reliable and predictable, but rigid and relatively expensive to change or scale. Because the carrier owns and manages the underlying network, you also benefit from end-to-end quality-of-service guarantees — but provisioning a new site can take weeks or months.
SD-WAN (Software-Defined WAN) is an intelligent overlay that combines multiple ordinary connections — leased lines, full fibre, broadband, 4G/5G — and steers each application over the best available path, with automatic failover and central control. Our SD-WAN and wider multi-site connectivity services are built around this model.
A useful way to think about it: MPLS is the network itself, while SD-WAN is a smart layer that sits on top of whatever connectivity you already have and makes better use of it.
Head-to-head
The table below summarises how the two approaches differ across the factors that matter most when planning a wide-area network.
- Cost — MPLS is higher; SD-WAN is lower as it uses internet links.
- Flexibility — MPLS is slow to change; SD-WAN is fast and software-defined.
- Resilience — MPLS is a single path unless duplicated; SD-WAN has built-in multi-link failover.
- Cloud performance — MPLS backhauls via the core; SD-WAN uses a direct, optimised on-ramp.
- Management — MPLS is carrier-dependent; SD-WAN uses a central dashboard.
- Deployment speed — MPLS circuits can take weeks or months; SD-WAN can often be brought online quickly over existing links.
- Best for — MPLS suits legacy, predictable traffic; SD-WAN suits cloud-first, multi-site setups.
The cloud factor
This is often the deciding point. MPLS typically backhauls internet and cloud traffic through a central site, adding latency to services like Microsoft 365. SD-WAN sends that traffic directly out to the cloud from each site, improving performance where your applications actually live today. If most of your workload sits in Microsoft 365, this difference is significant.
The impact is most noticeable for real-time services such as Teams voice and video calls, where every extra hop adds latency and jitter. SD-WAN can also prioritise these applications over less time-sensitive traffic like file backups, so critical services stay responsive even when a link is busy.
Security considerations
MPLS is often described as inherently secure because traffic stays on a private carrier network, but it does not encrypt data or inspect it. SD-WAN typically builds encryption into every tunnel and integrates with cloud-delivered security, so branch traffic going straight to the internet is still filtered and protected. If you move to SD-WAN, plan how each site's local internet breakout will be secured rather than assuming the WAN handles it for you.
For many businesses this is where a managed approach pays off — pairing SD-WAN with consistent firewall policy and monitoring across every site.
Which should you choose?
For most modern, cloud-first businesses, SD-WAN offers similar reliability to MPLS with far more flexibility and lower cost. MPLS still suits some legacy or highly predictable environments, particularly where a carrier-backed service-level guarantee is a firm requirement. The strongest setups often pair SD-WAN with a dedicated leased line as the primary link and 4G/5G for failover. If you'd like help choosing the right design, our network consultancy team can review your sites and traffic.