Let’s be honest: the marketing folks in our industry have done a spectacular job selling the dream of “Software-Defined” everything.
If you read the brochures, you’d think SD-WAN is magic pixie dust. You sprinkle it over any cheap, commodity broadband connection, and suddenly you have a carrier-grade network that never fails. The narrative is that the hardware is dead, the physical layer is a commodity, and software is the savior.
I’m here to be the skunk at the garden party: Software cannot fix physics.
Don’t get me wrong—I love SD-WAN. It’s the brain of the modern network. It makes intelligent decisions, routes traffic efficiently, and gives us visibility we’ve never had before. But if the brain is brilliant and the legs are broken, you aren’t winning the race.
The “Ferrari on a Gravel Road” Problem
Think of your network like a high-performance sports car. SD-WAN is the engine—it’s powerful, tuned, and responsive. But the “Underlay”—the physical circuits, fiber, and broadband connections that actually carry the data—is the road.
If you take a Ferrari and try to drive it 100 km/hr (60MPH) down a potholed gravel logging road, two things will happen:
- You will not go 100 km/hr (60MPH).
- You will destroy the suspension.
The software (the car) can compensate for a lot. It has shock absorbers (Forward Error Correction) and navigation systems (Dynamic Routing) to help you avoid the biggest bumps. But eventually, the road wins. If the physical path is congested, jittery, or prone to outages, the user experience is going to suffer, no matter how much you spend on the software overlay.
Not All Internet is Created Equal
There is a persistent myth that “Internet is Internet.” The CFO loves this myth because they look at the price of a dedicated fiber circuit, compare it to the price of the “Business Broadband” package from the local cable co, and ask, “Why are we paying 10x more for the same speed?”
Here is the reality check:
- Dedicated Internet is like having your own lane on the highway. No matter how many cars are on the road, your lane is moving.
- Broadband is the shared on-ramp. At 3:00 PM, when the school across the street lets out and 500 kids start streaming 4K video, your “Business Class” bandwidth evaporates. Is your CRM more important than TikTok?
SD-WAN is great at masking these issues. It can duplicate packets—basically sending two copies of every letter just in case the mailman loses one. But that’s a band-aid. It eats up your bandwidth and masks the symptoms without curing the disease.
The Backbone Matters
We also need to talk about where that traffic goes once it leaves your building.
If you are using a bargain-basement ISP, your data might be hopping through four or five different networks before it reaches its destination (like Microsoft Azure or Salesforce). Every time your data hands off from one network to another, there is friction. There is latency. There is a chance for something to go wrong.
This is where the “Tier 1” concept matters. It’s not just marketing fluff. It’s about getting your car onto the main highway as fast as possible, rather than taking surface streets across town. The fewer hops between you and your cloud applications, the faster your Zoom call feels.
Pragmatism Over Perfection
Now, am I saying you need gold-plated dedicated fiber for every single branch office? Absolutely not. That’s a waste of money.
This is where the “Realist” approach kicks in. You need to match the Underlay to the Use Case.
- The Headquarters / Data Center: This is the castle. You need a moat and a drawbridge. Put in the high-quality, diverse fiber. This is where the heavy lifting happens.
- The Manufacturing Plant: If the line stops when the network drops, you can’t rely on a shared cable connection. You need reliability.
- The Small Sales Office: They are checking email and accessing a CRM. Here, you can absolutely save money. Get the cheap broadband, but pair it with a 5G wireless backup.
Don’t Forget the Foundation
We are living in a golden age of networking software. The tools we have today to secure and manage traffic are incredible.
But let’s not kid ourselves. You cannot code your way out of a backhoe cutting a fiber line. You cannot “software define” your way out of a congested local loop.
Build a solid foundation first. Get the plumbing right. Then, and only then, use the software to make it sing.
(This article inspired as followup from a webinar discussion I participated in discussing the evolution of Enterprise and the Edge).