Configuring Ospf Areas; Prerequisites; Configuring A Stub Area - HP 4800G Series Configuration Manual

To do...
Configure an OSPF area and
enter OSPF area view
Configure a description for
the area
Specify a network to enable
OSPF on the interface
attached to the network
A network segment can only belong to one area.
It is recommended to configure a description for each OSPF process to help identify purposes of
processes and for ease of management and memorization.
It is recommended to configure a description for each area to help identify purposes of areas and
for ease of management and memorization.

Configuring OSPF Areas

After splitting an OSPF AS into multiple areas, you can further configure some areas as stub areas or
NSSA areas as needed.
If connectivity between the backbone and a non-backbone area or within the backbone itself cannot be
achieved, you can configure virtual links to solve it.

Prerequisites

Before configuring an OSPF area, you have configured:
IP addresses for interfaces, making neighboring nodes accessible with each other at the network
layer.
OSPF basic functions.

Configuring a Stub Area

You can configure a non-backbone area at the AS edge as a stub area by configuring the stub
command on all the routers attached to the area. In this way, Type-5 LSAs, which describe AS external
routes, will not be flooded within the stub area, reducing the routing table size. The ABR generates a
default route into the stub area so that all packets destined outside of the AS are sent through the
default route.
To further reduce the routing table size and routing information exchanged in the stub area, you can
configure it as a totally stub area by using the stub [ no-summary ] command on the ABR. In this way,
neither AS external routes nor inter-area routing information will be distributed into the area. All the
packets destined outside of the AS or area will be sent to the ABR for forwarding.
Follow these steps to configure OSPF areas:
Use the command...
area area-id
description description
network ip-address
wildcard-mask
1-22
Remarks
Required
Not configured by default.
Optional
Not configured by default.
Required
Not configured by default.