Networking · 13 · 3 min read

VLANs

One physical switch, several separate networks. Like building walls inside one room.

Why use them

Security — guests can’t see the office PCs.
Less noise — broadcasts stay inside their own VLAN.
Order — split by team, not by where the cable is.

Access and trunk

An access port belongs to one VLAN (a PC plugs in here). A trunk port carries many VLANs between switches, marking each frame with an 802.1Q tag. To talk between VLANs you need a router or a layer 3 switch.