The MPLS-to-SD-WAN migration conversation is, in many cases, framed by people who are selling SD-WAN. That does not make the case for migration wrong — in many situations it is the right move — but it does mean that the trade-offs tend to get underplayed. This is an attempt at a more balanced view.

We manage both MPLS and SD-WAN deployments for clients across Canada. Our perspective is shaped by what actually happens in production, not by a vendor relationship with either technology category.

What MPLS Actually Provides

MPLS (Multiprotocol Label Switching) is a carrier-managed WAN technology. Traffic is routed across the carrier’s private network — it never touches the public internet. This has specific implications that SD-WAN cannot fully replicate:

• Predictable performance with hard QoS guarantees — MPLS circuits carry SLA commitments on latency, jitter, and packet loss that are enforced at the carrier level. For latency-sensitive applications like real-time voice and video in contact centre environments, this remains a genuine advantage.
• Security by isolation — Traffic on an MPLS circuit is isolated from the public internet at the physical layer. This is a meaningful security property for certain regulated industries and high-sensitivity workloads.
• Carrier accountability — When an MPLS circuit underperforms, there is a single carrier to hold accountable under a specific SLA.

What SD-WAN Actually Provides

SD-WAN is a software layer that manages traffic across multiple underlying WAN connections — typically broadband internet, LTE, and MPLS. The intelligence sits in the SD-WAN appliance or cloud service rather than in the carrier network.

• Significant cost reduction — MPLS is expensive, particularly for multi-site organisations. Replacing MPLS with broadband internet connections managed by SD-WAN typically reduces WAN costs by 40–70%.
• Flexibility and agility — Adding a new site on SD-WAN is faster and cheaper than provisioning an MPLS circuit.
• Application-aware routing — SD-WAN can route specific application traffic over specific links based on real-time performance measurement.
• Built-in redundancy — With multiple underlying connections, SD-WAN inherently provides failover capability that MPLS-only deployments need to engineer separately.

When to Stay on MPLS

There are scenarios where MPLS remains the right choice, or where a hybrid approach is more appropriate than a full migration.

If you operate a contact centre with real-time voice quality requirements and hard SLA commitments to customers, the performance guarantees of MPLS for voice traffic are difficult to replicate with internet-based connections. A hybrid model that keeps voice on MPLS while moving data traffic to SD-WAN over broadband is often the right architecture.

If you operate in a highly regulated industry with specific data sovereignty or network isolation requirements, the security properties of MPLS may be a compliance requirement rather than a preference.

When to Migrate to SD-WAN

For most multi-site mid-market organisations, the economics of SD-WAN are compelling and the performance trade-offs are manageable with proper design. The scenarios where migration makes the most sense:

• Multiple sites where MPLS circuit costs are a significant line item
• Organisations where cloud applications (Microsoft 365, Salesforce) represent the majority of WAN traffic
• Organisations that are growing through new site openings
• Organisations that need LTE failover and cannot cost-effectively build that into their existing MPLS architecture

The SD-WAN Migration Process

A well-executed SD-WAN migration is typically phased — starting with non-critical sites, validating performance in production, and then migrating business-critical locations once confidence in the architecture is established. Running MPLS and SD-WAN in parallel during the transition period is standard practice.

The most common mistake in SD-WAN migrations is underestimating the importance of the underlying internet connections. SD-WAN is not magic — if the broadband connections it rides on are inconsistent, the SD-WAN performance will be inconsistent.

If you are evaluating this decision for your organisation, the most useful starting point is an honest assessment of your current WAN traffic profile, application requirements, and what MPLS is actually costing you. We do this as part of our Unbreakable Internet and Telecom Services engagements.