DELL S50V User Manual

Open Shortest Path First (OSPFv2 and OSPFv3) | 693

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. 

Areas can be defined in such a way that the 

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. 

Router A

Router D

Router B

Router C

Router E

Router F

Router G

Router H

Router I

Router J

Router L

Router K

Router M

Area 100

Area 200

Area 300

Area 0