Let me explain my use of VLANs at my home. Traditionally I had a VLAN-capable switch in my comms room and enough cabling so that any device inside my home could have its own wired connection to that switch. I was using VLANs internally inside the switch to have fast communication between the devices belonging to same VLAN. The switch has a fancy feature (unsymetrical VLANs meaning a given port can belong to more than one VLAN and untag all packets
exiting that port) meaning I could do some device separation without any of them being aware of VLANs, including the router.
Then the number of wired devices at a particular place (living room) grew to the point I no longer had enough ethernet cables. So I had to install another VLAN capable device (in my case a RB951G-2HnD) and have VLAN trunk on single ethernet cable between the two devices.
And I really needed VLANs, I needed separate (either physical cables or VLANs) connections for the following services:
- home LAN
- guest LAN - VAP on WiFi with internet only access and limited speed
- IPTV - provider delivers multicast streams in a VLAN so I replicated that particular VLAN nside my home network
- internet for the IPTV set-top box - I don't want to make it a part of my home LAN and I don't want to expose it to the guest WiFi users
All those VLANs are used by 4 devices: WiFI AP, smart TV, IP set-top box, and home cinema receiver. I needed a smart device already for the second bullet (VLAN-tagged WiFi) and I really didn't have possibility to run 5 ethernet cables (in case I'd actually install 2 WiFi APs to have two different SSIDs on air).
My current setup (deploying RB device) allows me to do all of that using one ethernet cable. For a while the very same device also did the routing between my home and internet (I get internet via VDSL and I used the existing VLAN switch do create another VLAN for PPPoE connection ... I could safely run that through my existing ethernet cables without fear of exposing my LAN to evil internet.
Now I actually have two RB951G-2HnD devices, one acting mainly as router and the other one performing as switch/AP. But I have kind of hardware redundancy: if one device fails, I can run my home network with only two out of three devices (even my 24-port switch can fail, some less important device might become temporarily unconnected) in case of failure .. and that gives me time to purchase another RB device (I'm thinking of cheapest xxxRM device)