area (OSPF)

Usage Scenario

All devices in a large-scale network run OSPF and a large number of OSPF packets are transmitted on the network with the expansion of the network. This leads to a large LSDB on each device. In this case, the bandwidth utilization is reduced.

OSPF resolves this problem by partitioning an AS into different areas. An area is regarded as a logical group and each group is identified by an area ID.

Configuration Impact

After OSPF partitions the AS into different areas, functions, such as the timer, filter, and summarization, of multiple routers in the same area, can be planned and configured uniformly in the area. Therefore, the size of the LSDB is reduced and the network performance is improved.

Prerequisites

Run the ospf command before you run the area command the first time to start the OSPF process and enter the OSPF view.

Precautions

• At the border of an area resides a router instead of a link.
• A network segment or a link belongs to only one area. The area to which each OSPF interface belongs must be specified.
• The backbone area is responsible for forwarding inter-area routing information. The routing information between the non-backbone areas must be forwarded through the backbone area.
• All non-backbone areas maintain the connectivity with the backbone area and the backbone areas in different OSPF areas maintain the connectivity with each other.