Configuring the Cisco router
The configuration for the Cisco router in this example is the same as in the basic example, except we add VLAN_300. Each of the three companies has its own subnet assigned to it.
The IP addressees assigned to each VLAN on the router are the gateway addresses for the VLANs. For example, devices on VLAN_100 would have their gateway set to 10.11.0.1/255.255.0.0.
!
interface FastEthernet0/0
switchport trunk encapsulation dot1q
switchport mode trunk
!
interface FastEthernet0/0.1
encapsulation dot1Q 100
ip address 10.11.0.1 255.255.0.0
!
interface FastEthernet0/0.3
encapsulation dot1Q 200
ip address 10.12.0.1 255.255.0.0
!
The router has the following configuration:
Port 0/0.1 | VLAN ID 100 |
Port 0/0.3 | VLAN ID 200 |
Port 0/0 | 802.1Q trunk |