Cuda 12000 IP Access Switch CLI-based Administration Guide
Configuring OSPF 313
Configuring OSPF Virtual Interfaces
OSPF requires that all areas be attached to the OSPF backbone area (area
0.0.0.0). However, you may encounter situations in which you cannot
connect an OSPF area directly to the backbone. If your Cuda 12000 is an
area border router between one area that is physically connected to the
OSPF backbone and one area that is not, you can create a virtual interface on
your Cuda 12000 to connect the non-contiguous area to the OSPF
backbone.
OSPF uses virtual interfaces for the following purposes:
■Connecting areas that are not physically connected to the backbone.
■Repair the backbone if a break in backbone continuity occurs.
Before you configure a virtual interface on your Cuda 12000, make sure
that:
■The OSPF backbone (area 0) is configured.
■You know the area ID of the transit area, which is the area that connects
the non-contiguous area to the backbone.
■You know the router ID of the OSPF neighbor that acts as the ABR
between the transit area and the backbone.
For example, if your Cuda 12000 is an ABR between an area that is
contiguous to the backbone (area 0.0.0.1) and an area that is not
contiguous to the backbone (area 0.0.0.2), as shown in Figure 14-3.