SD-WAN rarely disappoints on paper. It disappoints when twelve sites are cut over on one weekend, with applications nobody documented and policies written the night before.
Start with discovery, not hardware
Before ordering a single appliance, inventory sites, circuits, contract end dates, and the applications that actually matter. Traffic profiles decide the design; the design decides the equipment.
A sequence that works
- Overlay SD-WAN on existing MPLS so you can roll back at any point
- Pilot two sites with different profiles, such as a plant and a branch
- Codify application policy for voice, ERP, and guest traffic
- Migrate in waves, retiring MPLS circuits only after 30 clean days
- Hand the finished topology to the NOC with monitoring in place
Keep one owner
The most common source of migration pain is split ownership between a carrier, a VAR, and an internal team. When the underlay, overlay, and support desk belong to one provider, cutover nights get short and boring, which is exactly what you want.
