3Com Switch 4800G 24-Port Configuration Manual page 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
Switch A
Vlan- int100
10.1.1.1 /24
Vlan- int2 00
10 .2.1.1/24
Vlan -int200
Area 1
10 .2 .1.2/24
Stub
Vlan -int300
10.4.1.1/24
Switch C
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
Intra 10.2.1.1
Inter 10.3.1.1
Inter 10.5.1.1
# Display OSPF routing table information on Switch C.
[SwitchC] display ospf routing
OSPF Process 1 with Router ID 10.4.1.1
Routing for Network
Destination
10.2.1.0/24
10.3.1.0/24
10.4.1.0/24
Area 0 Switch B
Vlan -int100
10 .1 .1.2/24
Vlan -int2 00
10.3.1.1 /24
Area 2
Vlan- int3 00
10 .5.1.1/24
Switch D
Area
0.0.0.1
0.0.0.1
0.0.0.1
Routing Tables
Cost Type NextHop
3 Transit 10.2.1.2
7 Inter 10.2.1.1
3 Stub 10.4.1.1
OSPF Configuration Examples
Vlan -int200
10.3.1.2/24
ASBR
Cost Nexthop
3 10.2.1.1
5 10.2.1.1
7 10.2.1.1
AdvRouter
10.2.1.1
10.2.1.1
10.4.1.1
313
RtType
ABR
ABR
ASBR
Area
0.0.0.1
0.0.0.1
0.0.0.1