Chapter 10 Install and System Administration for FortiOS 5.0 : VLANs : VLANs in transparent mode : Configure the Cisco switch and router : Configure the Cisco router
  
Configure the Cisco router
You need to add a configuration file to the Cisco Multiservice 2620 ethernet router. The file defines the VLAN subinterfaces and the 802.1Q trunk interface on the router. The 802.1Q trunk is the physical interface on the router.
The IP address for each VLAN on the router is the gateway for that VLAN. For example, all devices on the internal VLAN_100 network will have 10.100.0.1 as their gateway.
Add this file to the Cisco router:
!
interface FastEthernet0/0
!
interface FastEthernet0/0.1
encapsulation dot1Q 100
ip address 10.100.0.1 255.255.255.0
!
interface FastEthernet0/0.2
encapsulation dot1Q 200
ip address 10.200.0.1 255.255.255.0
!
The router has the following configuration:
Port 0/0.1
VLAN ID 100
Port 0/0.2
VLAN ID 200
Port 0/0
802.1Q trunk
See Also
Configure the Cisco switch and router
Configure the Cisco switch
Test the configuration