A VLAN is like putting up concrete barriers along the lanes of a highway - all the cars (devices on the network) can move to/from their destination, but they can't crash (interact) with cars in other lanes.  You're a bit safer locked into the lane (from other traffic lanes), and each lane can have specific rules placed on them, like speed limits, forced exits, or who can even enter the lane in the first place.   Additionally, the concrete barriers are able to be configured with multiple lanes at once, so a 5 lane highway might have "3 lanes of cars & trucks at 55mph, exit at #37" and "2 lanes of cars-only at 75mph, exit at #42".    Finally, the concrete barriers can raise/lower and rules applied via a central control station, without having to stop all traffic before making changes. ... View more