- A local area network, or LAN, is an Ethernet broadcast domain. All the hosts on the LAN can see each other.
- But sometimes you need a special-purpose host on multiple LANs that’s where the virtual LAN comes in handy
- VLAN, is an extra tag on Ethernet frames indicating that they belong on a different LAN than the default.
- Each VLAN is identified by a number from 1 to 4096.
- For a VLAN to function, the switch port your hosts connect to needs a VLAN configuration.
- Some switches auto-configure requested VLANs, while others require manual intervention.
- VLANs are sometimes described as 802.1Q.
VLAN Terminology
- A ==network trunk== combines multiple physical layers into one datalink layer.
- Your server gets two network cables, and you configure the server to group them together into one connection.
- This creates redundancy, so that a failure of one switch or one cable or one network card doesn’t disconnect the server from the network.
- These kinds of trunks are very useful and popular.