A virtual LAN, commonly known as a VLAN, is a group of hosts with a common set of requirements that communicate as if they were attached to the Broadcast domain, regardless of their physical location. A VLAN has the same attributes as a physical LAN, but it allows for end
stations to be grouped together even if they are not located on the same network switch. Network reconfiguration can be done through software instead of physically relocating devices.

VLAN Creation:

Switch(config)# vlan 10

Switch(config-vlan)# name anyname

Access Port Configuration:

Switch(config-if)# switchport mode access

Switch(config-if)# switchport nonegotiate

Switch(config-if)# switchport access vlan 10

Switch(config-if)# switchport voice vlan 15

Trunk Port Configuration:

Switch(config-if)# switchport mode trunk

Switch(config-if)# switchport trunk encapsulation dot1q

Switch(config-if)# switchport trunk allowed vlan 10,15-20

Switch(config-if)# switchport trunk native vlan 10