When SD-WAN first emerged and became the industry trend, many network engineers quickly declared:
“MPLS is dead.”
“SD-WAN fixes everything.”
But even after a decade, that narrative hasn’t proven true, and it never will.
The reason is simple:
SD-WAN is not a transport.
It is an orchestration layer.
MPLS, on the other hand, is a transport service.
SD-WAN does not replace MPLS by default, it can actually use MPLS as one of its underlay transports. It sits above the transports (MPLS, Internet, LTE, etc.) and intelligently steers traffic across them.
The right solution to choose starts with the business requirement and depends on what you're optimizing for not what's trending.
Before choosing the technology, ask:
- does uptime have an SLA?
- is application performance critical to revenue?
- are sites in remote or unstable ISP regions?
- is traffic mostly SaaS and cloud based?
- is security centralized or distributed?
Architecture follows answers.
MPLS - Commitment First
Best when:
- client needs a predictable performance
- low latency between branches is required
- client needs a carrier-backed SLA
- require private circuit
- controlled routing
Weaknesses:
- Expensive
- Slow to provision
- Harder cloud breakout
Commitment is not something everyone asks for and it comes with a high price.
Internet VPN - Budget First
Best when:
- sites are small
- client is a SMB
- budget is constrained
- traffic is mostly SaaS
- downtime tolerance is reasonable
- fast deployment
- simple design is admired
Weaknesses:
- No SLA guarantees
- ISP path unpredictability
- Performance variability
Budget is not the only point for choosing a technology, if you are doing so you are doing procurement not architecture.
SD-WAN - Automated Control
Best when:
- client has many transports which needs orchestration
- applications have different priorities
- client needs centralized policy control
- cloud first architecture is in place
- dynamic steering needed
- application aware routing
- better bandwidth utilization
- integrated security (some vendors)
Weaknesses:
- Careful planning needed to achieve results
- Operational complexity
- Vendor lock-in
- Added costs
SD-WAN is utilizing the MPLS and Internet VPN and perform orchestration over imperfect links automatically to achieve the results.
Instead of asking "What's better?" ask:
- What is the cost of application unreliability?
- What is the cost of latency to the business?
- What is more preferred? Guaranteed performance or Intelligent adaption?
- Need optimization for stability or flexiblity?
- Is your team ready to operate a policy-driven WAN?
Final Thought
SD-WAN is cleary the future for most global scale enterprises; for some, a well-designed MPLS VPN or even an Internet VPN can still be entirely sufficient and can be ideal in certain scenarios, even in 2026. Honestly it depends on the trade-offs which are aligning trasnport characteristics with business impact.
