Configuring Ospf Area Parameters - 3Com Switch 4800G 24-Port Configuration Manual

294 C 28: OSPF C
HAPTER
Configuring OSPF
Area Parameters
ONFIGURATION
To ensure OSPF stability, you need to decide on router IDs and configure them
manually. Any two routers in an AS must have different IDs. In practice, the ID of a
router is the IP address of one of its interfaces.
Enable an OSPF process
■
The system supports OSPF multi-process. When a router runs multiple OSPF
processes, you need to specify an ID for each process, which takes effect locally
and has no influence on packet exchange between routers. Therefore, two routers
having different process IDs can exchange packets.
Configure an area and specify networks in the area
■
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.
Follow these steps to configure OSPF basic functions:
To do...
Enter system view
Enable OSPF and enter its view
Configure a description for the OSPF
process
Configure an OSPF area and enter
OSPF area view
Configure a description for the area description description
Specify a network to enable OSPF
on the interface attached to the
network
n
An OSPF process ID is unique.
■
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.
Splitting an OSPF AS into multiple areas reduces the number of LSAs in the
networks and extends the 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, and for this reason, NSSA was introduced.
In NSSA areas, Type-7 LSAs (NSSA External LSAs) can be advertised. Type 7 LSAs
originate from the ASBR in a NSSA area. When arriving at the ABR in the NSSA
Use the command...
system-view
ospf [ process-id | router-id
router-id ] *
description description
area area-id
network ip-address
wildcard-mask
Remarks
-
Required
Optional
Not configured by default
Required
Not configured by default
Optional
Not configured by default
Required
Not configured by default