beautypg.com

1 ospf area configuration – Planet Technology WGS3-2620 User Manual

Page 197

background image

WGS3 Layer 3 Switch User’s Manual

- 189 -

5.7.5.2.3.1 OSPF Area Configuration

OSPF protocol broadcast messages (i.e., Link State Advertisements) are restricted by area to limit their

impact on network performance. Before assigning an Area ID to a specific OSPF interface, you must first

specify the Area ID in this table. Each entry in this table identifies a logical group of OSPF routers that

actively exchange Link State Advertisements (LSAs) to ensure that they share an identical view of the

network topology. You can configure the area as a normal one which can send and receive external Link

State Advertisements (LSAs), a stubby area that cannot send or receive external LSAs, or a

not-so-stubby area (NSSA) that can import external route information into its area.


Parameter Description

Area ID

An OSPF area identifier configured for a group of OSPF routers. (For information

on how to assign this identifier to a specific interface, see4.5.6.1.5 Configuring

OSPF.)

Type

Indicates area type:

Normal – An area which can send or receive external route information.

Stub – An area which cannot send or receive external route information. It relies

on a single default route provided by its Area Border Router (ABR) to access

destinations outside of the stub. A stub can be used to reduce the amount of

topology data that has to be exchanged over the network.

NSSA – A not so stubby area cannot send but can receive external route

information. The ABR imports external routes and floods this information to all

routers within the NSSA.

An Autonomous System Boundary Router (ASBR) can import external routes and flood this information

to the entire Autonomous System.