area (OSPF)

Usage Scenario

The number of devices increases with the expansion of a network. This leads to a large LSDB on every OSPF-enabled device on a large-scale network. Route flapping frequently occurs and as such, a large number of OSPF packets are transmitted on the network. This wastes bandwidth resources.

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 a unique area ID.

Configuration Impact

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

Prerequisites

An OSPF process has been started using the ospf command.

Precautions

• At the border of an area resides a switch instead of a link.
• A network segment or a link belongs to only one area. Specify the area to which each OSPF interface belongs.
• 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 must maintain connectivity with the backbone area. The backbone area must also maintain connectivity within itself.