Software-defined networking, without the vendor gloss
SDN Hub is an independent resource that explains how programmable networks actually work — from the split between control and data planes to the controllers that run modern fabrics.
SDN suffers from a vocabulary problem more than a technical one. Every vendor uses the same four words to mean slightly different things, and a newcomer ends up believing the concepts are harder than they are. They are not. The core idea fits in a sentence, and most of the rest follows from it.
The control plane
Why separating decision-making from packet forwarding changed network design.
OpenFlow & friends
The protocols that let a controller program switches directly.
Controllers
ONOS, OpenDaylight and Ryu — what each is good for.
Automation
From CLI scripts to intent-based networking.