ADC CUDA 3 - Manual (Page 301)

Cuda 12000 IP Access Switch CLI-based Administration Guide
Configuring OSPF 299
OSPF Areas
To address large link-state databases, OSPF employs areas, which are groups
of OSPF routers that exchange topology information. Designated routers
only send LSAs to routers in the same area. If an autonomous system (AS)
has one area, all routers in the AS receive LSAs; however, if the AS consists of
many areas, LSAs are only sent to the appropriate areas, which minimizes
traffic and the link-state database size. Using areas, the AS works much like
a group of small networks.
Figure 14-1 Illustrates the concept of areas.
Figure 14-1 OSPF Areas
In this example, the AS consists of five areas. Each area represents smaller
networks within the AS, and maintains separate link-state databases. Area 0
is the backbone, connecting all areas within the AS.
Area 1
Area 2
Area 3 Area 4
Area 0
Autonomous System