Configuring A Stub Area; Configuring An Nssa Area - HP 6125XLG Configuration Manual

Configure IP addresses for interfaces to ensure IP connectivity between neighboring nodes.
•
• Enable OSPF.

Configuring a stub area

You can configure a non-backbone area at an AS edge as a stub area. To do so, issue the stub command
on all routers attached to the area. The routing table size is reduced because Type-5 LSAs will not be
flooded within the stub area. The ABR generates a default route into the stub area so 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, configure a
totally stub area by using the stub [ no-summary ] command on the ABR. AS external routes and
inter-area routes will not be distributed into the area. All the packets destined outside of the AS or area
will be sent to the ABR for forwarding.
A stub or totally stub area cannot have an ASBR because external routes cannot be distributed into the
area.
Virtual links cannot transit a stub area or totally stub area.
To configure an OSPF stub area:
Step
1. Enter system view.
2. Enter OSPF view.
3. Enter area view.
4. Configure the area as a stub
area.
5. (Optional.) Specify a cost
for the default route
advertised to the stub area.

Configuring an NSSA area

A stub area cannot import external routes, but an NSSA area can import external routes into the OSPF
routing domain while retaining other stub area characteristics.
Do not configure the backbone area as an NSSA area or totally NSSA area.
To configure an NSSA area, configure the nssa command on all the routers attached to the area.
To configure a totally NSSA area, configure the nssa command on all the routers attached to the area
and configure the nssa no-summary command on the ABR. The ABR of a totally NSSA area does not
advertise inter-area routes into the area.
Virtual links cannot transit a stub area or totally stub area.
To configure an NSSA area:
Command
system-view
ospf [ process-id | router-id
router-id | vpn-instance
vpn-instance-name ] *
area area-id
stub
[ default-route-advertise-always
| no-summary ] *
default-cost cost
58
Remarks
N/A
N/A
N/A
By default, no stub area is configured.
The default setting is 1.
The default-cost cost command takes
effect only on the ABR of a stub area or
totally stub area.