# MPLS vs SD-WAN: Why MPLS Is Still the Better WAN for Most

SD-WAN, often written SDWAN, is often presented as the replacement for MPLS. For a handful of internet-only sites it can be a reasonable choice. For organisations whose sites depend on shared systems, voice and each other, a private MPLS WAN from one accountable provider remains the stronger foundation, and the reasons are practical rather than nostalgic.

By Chris Byrd

27 October 2026

[Connectivity & WAN](https://netavo.com/insights)

## What each one actually is

An MPLS WAN is a private routed network operated by a provider. Each site connects into the provider's core, and traffic between sites travels across that core without touching the public internet. The provider designs the routing, carries the traffic and is responsible for the network between your sites.

SD-WAN is an overlay. Each site has one or more ordinary internet connections, often from different providers, and an SD-WAN appliance at each site builds encrypted tunnels across them and chooses which path to use. The network between your sites is still the internet; SD-WAN manages how traffic is sent across it.

That difference, a private network versus software steering traffic over public ones, is behind every point below.

## MPLS vs SD-WAN at a glance

| Aspect | MPLS WAN | SD-WAN |
| --- | --- | --- |
| Path between sites | The provider's private core network | Public internet, inside encrypted tunnels |
| Privacy | Private by design; traffic never crosses the internet | Depends on encryption to make internet paths acceptable |
| Performance | Known latency and loss across one operator's network | Varies with internet paths no one in the contract controls |
| Accountability | One provider for access, core and routing | A software vendor on top of several ISPs |
| Equipment | Any suitable router; no per-site overlay licence | An SD-WAN appliance and subscription at every site |
| A poor access line | Fixed at the access line, where the fault is | Steered around if another path exists, but not fixed |

## Private by design, not by encryption

With MPLS, traffic between sites never enters the public internet. Isolation is a property of the network itself, so a branch's traffic to head office is not exposed to the internet at any point between them.

SD-WAN reaches a similar outcome a different way: it accepts that traffic crosses the internet and encrypts it so that it is safe to do so. That works, but it means every site is an internet-connected device, the security of the WAN depends on the overlay's configuration being right everywhere, and the sites remain reachable from the internet in a way that private MPLS sites are not. Encryption still has a place on a private network for sensitive applications; on MPLS it is a choice, not the thing holding the design together.

## Predictable performance for voice and shared systems

An MPLS WAN runs across one operator's network, end to end. Latency and loss between sites are properties of that network, which the provider monitors and is responsible for, rather than the sum of several internet paths.

An SD-WAN appliance can measure its tunnels and move traffic to the better one, but it cannot change the internet paths beneath them. When congestion sits somewhere between two ISPs, neither the overlay nor your access providers control it. For organisations that run voice, central applications or remote desktops across the WAN, that unpredictability is the cost that matters most.

## One accountable provider

When a site on an MPLS WAN has a problem, one provider owns the access, the core and the routing between sites, and is responsible for finding the fault.

An SD-WAN estate typically involves an SD-WAN vendor or integrator plus a different ISP, sometimes two, at every site. During an incident the overlay reports its tunnels are up, each ISP reports no fault on its line, and the customer is left gathering evidence across several organisations. We set out that operational argument in more detail in [private WAN or internet VPN for multiple sites](https://netavo.com/insights/private-wan-vs-vpn).

## No per-site appliance licences

SD-WAN is usually sold as an appliance and a subscription at every branch, renewed for the life of the estate, on top of the internet connections themselves. The overlay becomes a recurring cost per site and a dependency on one vendor's platform.

An MPLS WAN needs a suitable router at each site, and that can be your own. There is no overlay licence to renew, and nothing ties the network to a single vendor's appliances.

## SD-WAN cannot fix a poor connection

SD-WAN's main promise is that it chooses the best available path. That only helps if a better path exists. A site with one weak line, or two lines that share the same duct, cable or exchange, gains little: the overlay can measure the problem but cannot repair it, and cannot create capacity the access lines do not have.

Resilience comes from the connections themselves: the right access for the site, a genuinely diverse second path where the site needs one, and a network that is monitored and fixed where faults occur. That is true on either design, but on MPLS it is the provider's job rather than a problem the overlay is left to hide.

## Where SD-WAN is a reasonable choice

SD-WAN suits estates of many small sites that mainly need internet access, where cloud applications are reached over the internet anyway, sites exchange little traffic with each other, and the lowest cost per site matters more than predictable performance between them. It can also be a pragmatic way to join together connections from many local providers in places a single network cannot reach.

For organisations whose sites depend on shared systems, voice and each other, those trade-offs usually point the other way.

## One private network for sites, failover and devices

A Netavo MPLS WAN is not limited to fixed sites. Each site can have a mobile second path that stays on the same private network, so a failover keeps the site on the WAN rather than dropping it onto the internet. Fleets of [IoT SIMs](https://netavo.com/services/iot) can join the same MPLS network too, so devices, vehicles and remote equipment reach central systems privately, alongside the fibre and Ethernet sites.

Netavo provides [private MPLS networks](https://netavo.com/services/mpls) over FTTP, FTTC, Ethernet and on-net Ethernet, carried on our own core network, with [AWS Direct Connect and Azure ExpressRoute](https://netavo.com/services/cloud-interconnect) on the same VPN. New to the terms? See [what is MPLS](https://netavo.com/insights/what-is-mpls) and [what is SD-WAN](https://netavo.com/insights/what-is-sd-wan); planning a move? Read [before you migrate from MPLS to SD-WAN](https://netavo.com/insights/mpls-to-sd-wan-migration).

## Common questions

### Is MPLS better than SD-WAN?

For organisations whose sites depend on shared systems and voice, usually yes. An MPLS WAN keeps traffic off the internet, gives predictable performance across one provider's network and has one accountable provider. SD-WAN suits many small internet-only sites where cost per site matters most.

### Is MPLS more secure than SD-WAN?

MPLS is private by design: traffic between sites never crosses the public internet. SD-WAN sends traffic across the internet and relies on encryption to protect it, so its security depends on the overlay being configured correctly at every site.

### Can SD-WAN improve a poor internet connection?

No. SD-WAN can move traffic to another path if a better one exists, but it cannot repair a poor access line or add capacity the line does not have.

### Does an MPLS WAN need special routers at every site?

No. An MPLS WAN needs a suitable router at each site, which can be the customer's own, and there is no per-site overlay licence.

### Can mobile failover and IoT SIMs join an MPLS WAN?

Yes. With Netavo, a site's mobile second path stays on the same private MPLS network, and IoT SIM fleets can join it so devices reach central systems privately.

### Does Netavo offer SD-WAN?

No. Netavo provides private MPLS WAN over FTTP, FTTC and Ethernet, carried on its own core network, with mobile failover.

## Related services and sectors

### [MPLS Network Provider: Private MPLS WAN for Business](https://netavo.com/services/mpls)

Any-to-any MPLS VPN on our own core, joining sites, cloud, IoT SIMs, voice and remote workers on one private WAN.

### [Leased Line, MPLS and WAN Reseller Partners](https://netavo.com/services/connectivity-partners)

Leased lines, business FTTP and MPLS WAN for resellers and partners, with a white-label portal, an availability and quote API and your own billing.

### [Private Cloud Interconnect: Direct Connect and ExpressRoute](https://netavo.com/services/cloud-interconnect)

AWS Direct Connect, Azure ExpressRoute and Google Cloud Interconnect joined to your MPLS WAN or IoT SIM fleet.

### [Retail & Multi-site Estates](https://netavo.com/sectors/retail-and-multi-site)

Fibre, Ethernet and private networking for branches and head offices, with mobile failover and estate telephony.

### [IT & Managed Service Providers](https://netavo.com/sectors/it-and-managed-service-providers)

Customer-site connectivity, private WAN, mobile failover and cloud voice delivered for IT and managed service providers.

## Put your sites on a private MPLS WAN

Tell us which sites need to work together, what runs between them and where they are. We will come back with a design, the access options at each address and pricing.

[Work with us](https://netavo.com/work-with-us)

Chris Byrd

CTO, Netavo Global Data Services Ltd

Chris leads Netavo's engineering: the AS208802 network, its broadband and BNG platforms, and the mobile core behind its IoT SIMs.

[Chris Byrd on LinkedIn](https://www.linkedin.com/in/chrisbyrd)

Source: https://netavo.com/insights/mpls-vs-sd-wan