Background: Know: VLAN Recognize: Prerequisites - switch
VLAN allow NetOp to control membership of broadcast domain (LANs) rather than all ports of a switch belonging to same LAN and routers separating LANs.
The benefits of using VLAN:
i. Limits the size of broadcast domains
ii. Improves network performance
iii. Controlled broadcast activity and better network security
In VLAN scenario, the trunk contains all the information from all VLAN, and the trunk port is effectively to switch information between two members in the same VLAN. As shown in the figure above, each switch port is assigned to a VLAN. This logically split switch into multiple switches. The port 10 called "trunk port" is assigned to multiple VLANs. The trunk port contains all of the information in VLAN 2018, VLAN 3 and VLAN 76, so that it is simple to switch information in VLAN 2018. In other words in the figure above, the members in VLAN 2018 can switch information with the VLAN member on the right switch through the trunk port.
To see the example of where VLAN can be used click here