In what part exactly?
The example is not perfect I can see that myself. If I read into it too much there could be an overlap with concurrency, e.g. the (IO) tasks awaited & delegated to the OS could be considered a form of concurrency but other then that I do think it’s close to describing how async usually works.
How did you fail?
VLANs (Virtual LANs) are for isolating devices from each other (while still being plugged to the “LAN” ports of the same router).