Area Types - Dell Force10 C150 Configuration Manual

Figure 32-1. Autonomous System Areas
Router F
Router E
Router D
Area 100
Router B
Router A

Area Types

The Backbone of the network is Area 0. It is also called Area 0.0.0.0 and is the core of any Autonomous
System (AS). All other areas must connect to Area 0.
backbone is not contiguous. In this case, backbone connectivity must be restored through virtual
links. Virtual links are configured between any backbone routers that share a link to a
non-backbone area and function as if they were direct links.
An OSPF backbone is responsible for distributing routing information between areas. It consists of all
Area Border Routers, networks not wholly contained in any area, and their attached routers.
The Backbone is the only area with an default area number. All other areas can have their Area ID assigned
in the configuration.
Figure 32-1 shows Routers A, B, C, G, H, and I are the Backbone.
Router K
Area 200
Router C
Area 0
Router I
Router J
Area 300
Areas can be defined in such a way that the
Router M
Router L
Router G
Router H
Open Shortest Path First (OSPFv2 and OSPFv3) | 693