Okay, I've been watching lots of YouTube videos about switches and I've just made myself more confused. Managed versus unmanaged seems to be having a GUI versus not having a GUI, but why would anyone want a GUI on a switch? Shouldn't your router do that? Also, a switch is like a tube station for local traffic, essentially an extension lead, so why do some have fans?
A managed switch allows you to have vlans, routing, QoS, spanning tree protection etc. You don't necessarily need a gui, a lot of them are cli only, which is preferable but less user friendly if you're not used to it. Depending on your needs a managed switch can be overkill.
VLANs are an extension of the Ethernet technology, and operate on the link layer (OSI layer 2). They are handled by switches. VLANs can belong to different subnets, and communication between them requires routing, which happens on the network layer (OSI layer 3) on either routers or layer-3 switches, but VLANs themselves are handled by switches.
I recommend Network Chuck on youtube, his videos are very noob-friendly.
The router does the routing from one vlan into another. The switch has a funktion to apply the traffic with a specific vlan-tag.
E.g.
On the switch: to your PC vlan 3 could be applied and for your fridge vlan 25.
On the router: You can allow vlan 3 access to the Internet but vlan 25 not. For management purposes you could allow vlan 3 access to vlan 25 but not the other way around.
You’ve run up against the first thing that seems to really confuse people when they begin learning about networking.
What you thought of as a LAN is a LAN. A VLAN is a Virtual LAN. It’s the same concept but virtualized, allowing more than one LAN on hardware that is just physically a single LAN.
When most people are talking about setting up VLANs they are usually describing the creation of a separate layer 3 subnet and the creation of a VLAN ID that gets tagged to all packets that get sent on that separate subnet. This allows for both layer 2 and 3 separation of the virtual lans on a single physical network.
Conceptually it’s very similar to VM’s running on a single server.