3Com Switch 4800G 24-Port Configuration Manual page 315

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Configuring an OSPF
NSSA Area
[SwitchC] display ospf routing
OSPF Process 1 with Router ID 10.4.1.1
Routing for Network
Destination
0.0.0.0/0
10.2.1.0/24
10.4.1.0/24
Total Nets: 3
Intra Area: 2 Inter Area: 1
After this configuration, routing entries on the stub router are further reduced,
containing only one default external route.
Network requirements
The following figure shows an AS is split into three areas, where all switches run
OSPF. Switch A and Switch B act as ABRs to forward routing information between
areas.
It is required to configure Area 1 as an NSSA area, and configure Router C as the
ASBR to redistribute static routes into the AS.
Network diagram
Figure 95 Network diagram for OSPF NSSA area configuration
Switch A
Vlan- int100
10.1.1.1 /24
Vlan-int200
10.2.1 .1/24
Area 1
Vlan -int200
NSSA
10 .2 .1.2/24
ASBR
Vlan -int300
Switch C
10 .4.1.1/24
Configuration procedure
1 Configure IP addresses for interfaces.
2 Configure OSPF basic functions (refer to "Configuring OSPF Basic Functions" on
page 310).
3 Configure Area 1 as an NSSA area.
# Configure Switch A.
[SwitchA] ospf
[SwitchA-ospf-1] area 1
[SwitchA-ospf-1-area-0.0.0.1] nssa default-route-advertise no-summary
[SwitchA-ospf-1-area-0.0.0.0] quit
[SwitchA-ospf-1] quit
Routing Tables
Cost Type NextHop
4 Inter 10.2.1.1
3 Transit 10.2.1.2
3 Stub 10.4.1.1
ASE: 0 NSSA: 0
Area 0 Switch B
Vlan -int100
Vlan -int200
10 .1 .1.2/24
10 .3.1.1/24
Area 2
Vlan- int3 00
10 .5.1.1/24
Switch D
OSPF Configuration Examples
AdvRouter
10.2.1.1
10.4.1.1
10.4.1.1
Vlan -int200
10.3.1.2/24
315
Area
0.0.0.1
0.0.0.1
0.0.0.1