VLAN management is quite different on ISR routers than on Catalyst switches. VLAN can be used as 802.1q subinterfaces for routed interfaces or with a switch-like configuration on Ethernet Switch Modules (HWIC-4ESW for example)
Subinterface configuration (routed interfaces)
Layer 3 router interfaces cannot be configured in switch mode using "switchport" command on a Cisco ISR router. However, 802.1q trunks interconnexion is supported on these interfaces using the subinterface feature.
Virtual layer 3 interfaces are bound to the physical port using the interface <interface name>.<inderface id> command, <interface id> beeing the subinterface ID. For better configuration readability, the <interface id> is usually configured with the <vlan id> value. The encapsulation dot1Q <vlan id> maps the trafic flowing with the 802.1q vlan id (tagged) to the subinterface.
In the example below, FastEthernet0/0.20 is a subinterface bound to the FastEthernet0/0 physical interface. FastEthernet 0/0.20 is configured to process trafic flowing on vlan 20 in the 802.1q trunk connected to the FastEthernet 0/0 physical router interface.
interface FastEthernet0/0.20
encapsulation dot1Q 20
ip address 10.20.10.1 255.255.255.0
interface FastEthernet0/0.30
encapsulation dot1Q 30
ip address 10.30.10.1 255.255.255.0
VLAN database (ESW module)
If an EtherSwitch Service Module (HWIC-4ESW for example) has been installed on the ISR router, VLAN for that module can be configured using the vlan database in Packet Tracer 7.2. Port membership to the vlan is configured in the same way than on a Catalyst switch using the "switchport access vlan <vid>" commmand.
Router(config)#interface Vlan100 Router(config-if)#description mgmt Router(config-if)#ip address 192.168.10.100 255.255.255.0 Router#vlan database % Warning: It is recommended to configure VLAN from config mode, as VLAN database mode is being deprecated. Please consult user documentation for configuring VTP/VLAN in config mode. Router(vlan)#vlan 100 VLAN 100 added: Name: VLAN0100 Router(vlan)# %LINK-5-CHANGED: Interface Vlan100, changed state to up
The show vlan-switch command displays the VLAN configured on the EtherSwitch Service Module of the ISR router.
Router#show vlan-switch
VLAN Name Status Ports ---- -------------------------------- --------- ------------------------------- 1 default active 100 VLAN0100 active 1002 fddi-default act/unsup 1003 token-ring-default act/unsup 1004 fddinet-default act/unsup 1005 trnet-default act/unsup VLAN Type SAID MTU Parent RingNo BridgeNo Stp BrdgMode Trans1 Trans2 ---- ----- ---------- ----- ------ ------ -------- ---- -------- ------ ------ 1 enet 100001 1500 - - - - - 0 0 100 enet 100100 1500 - - - - - 0 0 1002 fddi 101002 1500 - - - - - 0 0 1003 tr 101003 1500 - - - - - 0 0 1004 fdnet 101004 1500 - - - ieee - 0 0 1005 trnet 101005 1500 - - - ibm - 0 0
Layer 3 configuration of a vlan interface is achieved using the interface vlan <vid>
Router#show ip interface brief Interface IP-Address OK? Method Status Protocol GigabitEthernet0/0 unassigned YES unset administratively down down GigabitEthernet0/1 unassigned YES unset administratively down down GigabitEthernet0/2 unassigned YES unset administratively down down Vlan1 unassigned YES unset administratively down down Vlan100 192.168.10.100 YES manual up down