Autonomous System
An Autonomous System can be divided into multiple areas. Each area represents a collection of contiguous networks and hosts. Areas limit the amount of advertisements sent within the network. This is known as flooding. An area is represented in OSPFv2 by either an IP address or a number.
Figure 21
OSPF operating in a network
NOTE
For details of components and virtual links, refer to
OSPF components and roles and
Virtual links, respectively.
Once OSPFv2 is enabled on the system, the user assigns an IP address or number as the area ID for each area. The area ID is representative of all IP addresses (subnets) on a router port. Each port on a router can support one area.