Configuring virtual links
If an Area Border Router (ABR) does not have a physical link to a backbone area, a
virtual link can be configured between that ABR and another device within the same
area that has a physical link to a backbone area.
A virtual link is configured, and a virtual link endpoint on two devices, ABR1 and ABR2, is defined.
- On ABR1, enter the
configure terminalcommand to access global configuration mode. - Enter the
router ospfcommand to enter OSPF router configuration mode and enable OSPFv2 on the device. - Enter the
areacommand to assign an OSPFv2 area ID. - Enter the
areacommand to assign an OSPFv2 area ID. - Enter the
area virtual-linkcommand and the ID of the OSPFv2 device at the remote end of the virtual link to configure the virtual link endpoint. - On ABR2, enter the
configure terminalcommand to access global configuration mode. - Enter the
router ospfcommand to enter OSPFv2 router configuration mode and enable OSPFv2 on the device. - Enter the
areacommand to assign an OSPFv2 area ID. - Enter the
areacommand to assign an OSPFv2 area ID. - Enter the
area virtual-linkcommand and the ID of the OSPFv2 device at the remote end of the virtual link to configure the virtual link endpoint.
The following example configures a virtual link between two devices.
ABR1: device1# configure terminal device1(config)# router ospf device1(config-ospf-router)# area 0 device1(config-ospf-router)# area 1 device1(config-ospf-router)# area 1 virtual-link 10.2.2.2 ABR2: device2# configure terminal device2(config)# router ospf device2(config-ospf-router)# area 1 device2(config-ospf-router)# area 2 device2(config-ospf-router)# area 1 virtual-link 10.1.1.1