3Com Switch 8800 Advanced Software V5 Configuration Guide

324 CHAPTER 30: OSPF CONFIGURATION
The system supports OSPF multi-instance. You can configure an OSPF process to
run in a specified VPN instance to configure an association between the two.
The configurations for routers in an area are performed on the area basis. Wrong
configurations may cause communication failures, even routing information block
or routing loops between neighboring routers.
To configure OSPF basic functions, use the following commands:
n
■ An OSPF process ID is unique, including the process ID for OSPF multi-instance,
which cannot be the same as any previously configured ID.
■ 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
Area Parameters
Splitting an OSPF AS into multiple areas reduces the number of LSAs on networks
and extends OSPF application. For those non-backbone areas residing on the AS
boundary, you can configure them as Stub areas to further reduce the size of
routing tables on routers in these areas and the number of LSAs.
A stub area cannot redistribute routes, thus introducing the concept of NSSA,
where type 7 LSAs (NSSA External LSAs) are advertised. Type 7 LSAs originate from
the ASBR in a NSSA area. When arriving at the ABR in the NSSA area, these LSAs
will be translated into type 5 LSAs for advertisement to other areas.
Non-backbone areas exchange routing information via the backbone area.
Therefore, the backbone and non-backbone areas, including the backbone itself
must maintain connectivity.
If necessary physical links are not available for this connectivity maintenance, you
can configure virtual links to solve it.
To do... Use the command... Remarks
Enter system view system-view -
Enable OSPF and enter its
view
ospf [ process-id | router-id
router-id | vpn-instance
instance-name ] *
-
Configure a description for
the OSPF process
description description Optional
Not configured by default
Configure an OSPF area and
enter OSPF area view
area area-id Required
Not configured by default
Configure a description for
the area
description description Optional
Not configured by default
Specify a network to enable
OSPF on the interface
attached to the network
network ip-address
wildcard-mask
Required
Not configured by default