VLANs

Description

A virtual LAN (VLAN) is a logical overlay network that groups together a subset of devices that share a physical LAN, isolating the traffic for each group. A LAN is a group of computers or other devices in the same place -- e.g., the same building or campus -- that share the same physical network.

VLANs operate at Layer 3

Source

Create VLANs

Switch(config)# vlan {number}
Switch(config-vlan)# name {name}

Set Access and Trunk Ports

For this to work you must select an interface using

Switch(config)# interface range FastEthernet 0/{port}

For an individual port type

Switch(config-if)# switchport 'access or trunk' vlan {port}

Configure interfaces in "ranges"

Switch(config)# interface range FastEthernet 0/{start port}-{stop port}

Assigning VLAN IP

Router(config)# interface vlan <vlan-id>
Router(config-if)# ip address <ip-address> <subnet>

VLAN State

This will make sure the vlan is in the up state. For the love of all make sure that you do this to vlan 1!

Router(config)#interface vlan {vlan-id}
Router(config-if)#no shutdown