Assigning the routing switch to OSPF areas

After you globally enable OSPF on the routing switch (see Changing the RFC 1583 OSPF compliance setting), use this command to assign one or more OSPF areas within your AS. A routing switch can belong to one area or to multiple areas. (Participation in a given, assigned area requires configuring one or more VLANs or subnets and assigning each to the desired area.
  • If you want the VLANs and any subnets configured on the routing switch to all reside in the same area, you need to configure only that one area. (In this case, the routing switch would operate as an internal router for the area.)

  • If you want to put different VLANs or subnets on the routing switch into different areas, you need to re-execute this command for each area. (In this case, the routing switch will operate as an ABR for each of the configured areas.)

NOTE:

Each ABR must either be directly connected to the backbone area (0) or be configured with a virtual link to the backbone area through another ABR that is directly connected to the backbone area. See Configuring an ABR to use a virtual link to the backbone.