OSPF Configuration Examples 313
Configuring an OSPF
Stub Area
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. Switch D acts as the ASBR to redistribute routes (static routes).
It is required to configure Area 1 as a Stub area, reducing LSAs to this area without
affecting route reachability.
Network diagram
Figure 94 Network diagram for OSPF Stub area configuration
1 Configure IP addresses for interfaces (omitted).
2 Configure OSPF basic functions (refer to “Configuring OSPF Basic Functions” on
page 310).
3 Configure Switch D to redistribute static routes.
[SwitchD] ip route-static 3.1.2.1 24 10.5.1.2
[SwitchD] ospf
[SwitchD-ospf-1] import-route static
[SwitchD-ospf-1] quit
# Display ABR/ASBR information on Switch C.
[SwitchC] display ospf abr-asbr
OSPF Process 1 with Router ID 10.4.1.1
Routing Table to ABR and ASBR
Type Destination Area Cost Nexthop RtType
Intra 10.2.1.1 0.0.0.1 3 10.2.1.1 ABR
Inter 10.3.1.1 0.0.0.1 5 10.2.1.1 ABR
Inter 10.5.1.1 0.0.0.1 7 10.2.1.1 ASBR
# Display OSPF routing table information on Switch C.
[SwitchC] display ospf routing
OSPF Process 1 with Router ID 10.4.1.1
Routing Tables
Routing for Network
Destination Cost Type NextHop AdvRouter Area
10.2.1.0/24 3 Transit 10.2.1.2 10.2.1.1 0.0.0.1
10.3.1.0/24 7 Inter 10.2.1.1 10.2.1.1 0.0.0.1
10.4.1.0/24 3 Stub 10.4.1.1 10.4.1.1 0.0.0.1
Area 0
Area 1
Stub
Area 2
Switch C
Vlan-int100
10.1.1.2/24
Vlan-int100
10.1.1.1/24
Vlan-int300
10.4.1.1/24
Vlan-int200
10.2.1.2/24
Switch B
Vlan-int200
10.3.1.1/24
Vlan-int200
10.3.1.2/24
Switch A
Vlan-int200
10.2.1.1/24
Vlan-int300
10.5.1.1/24
Switch D
ASBR
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