Dictionary · Networking Fundamentals
VLAN
VLAN — Virtual Local Area Network
Switching · Intermediate
A logical separation of switch ports into different broadcast domains. IEEE 802.1Q tags frames so one physical trunk can carry several of these networks.
Ports can behave as if they were on different switches even when they share hardware. A router or layer-3 switch is still required for devices in different groups to communicate.
Picture it
Staff computers and phones can share the hardware and still be separated. A router or layer-3 switch is still required for the groups to talk to each other.
Example: Staff computers are on VLAN 10 and phones are on VLAN 20. The uplink trunk carries both with 802.1Q tags.
Common misconception
- A logical split does not automatically block routed traffic. Inter-network traffic needs an explicit layer-3 path and policy.