Simple Model
Step by Step
R1
enable
conf ter
interface f 0/0
ip addr 10.10.10.1 255.255.255.0
no shutdown
exit
router ospf 1
network 10.10.10.0 0.0.0.255 area 0
exit
end
R2
enable
conf ter
interface f 0/0
ip addr 10.10.10.2 255.255.255.0
no shutdown
exit
router ospf 1
network 10.10.10.0 0.0.0.255 area 0
exit
end
🎉
Single Area Model
Topology
Step by Step
PC1
ip 10.10.10.10/24 10.10.10.1
PC2
ip 50.50.50.50/24 50.50.50.1
R1
enable
conf ter
interface f 0/0
ip addr 10.10.10.1 255.255.255.0
no shutdown
exit
interface f 0/1
ip addr 20.20.20.1 255.255.255.0
no shutdown
exit
router ospf 1
network 10.10.10.0 0.0.0.255 area 0
network 20.20.20.0 0.0.0.255 area 0
exit
end
R2
enable
conf ter
interface f 0/0
ip addr 20.20.20.2 255.255.255.0
no shutdown
exit
interface f 0/1
ip addr 30.30.30.1 255.255.255.0
no shutdown
exit
router ospf 1
network 20.20.20.0 0.0.0.255 area 0
network 30.30.30.0 0.0.0.255 area 0
exit
end
R3
enable
conf ter
interface f 0/0
ip addr 30.30.30.2 255.255.255.0
no shutdown
exit
interface f 0/1
ip addr 40.40.40.1 255.255.255.0
no shutdown
exit
router ospf 1
network 30.30.30.0 0.0.0.255 area 0
network 40.40.40.0 0.0.0.255 area 0
exit
end
R4
enable
conf ter
interface f 0/0
ip addr 40.40.40.2 255.255.255.0
no shutdown
exit
interface f 0/1
ip addr 50.50.50.1 255.255.255.0
no shutdown
exit
router ospf 1
network 40.40.40.0 0.0.0.255 area 0
network 50.50.50.0 0.0.0.255 area 0
exit
end
🎉
Test
On Any Router
show ip route
show ip ospf neighbor
Note
In this configuration, we didn’t configure route ID or loopback address. This is not recommended since the change of interface status might cause unstable of DR and BDR. In the next model, we will configure the router-id and loopback address for every router..
Multiple Area Model
Topology
Step by Step
PC1
ip 10.10.10.10/24 10.10.10.1
PC2
ip 50.50.50.50/24 50.50.50.1
R1
enable
conf ter
interface f 0/0
ip addr 10.10.10.1 255.255.255.0
no shutdown
exit
interface f 0/1
ip addr 20.20.20.1 255.255.255.0
no shutdown
exit
interface loopback 0
ip addr 1.1.1.1 255.255.255.255
no shutdown
exit
router ospf 1
router-id 1.1.1.1
network 10.10.10.0 0.0.0.255 area 1
network 20.20.20.0 0.0.0.255 area 1
exit
end
R2
enable
conf ter
interface f 0/0
ip addr 20.20.20.2 255.255.255.0
no shutdown
exit
interface f 0/1
ip addr 30.30.30.1 255.255.255.0
no shutdown
exit
interface loopback 0
ip addr 2.2.2.2 255.255.255.255
no shutdown
exit
router ospf 1
router-id 2.2.2.2
network 20.20.20.0 0.0.0.255 area 1
network 30.30.30.0 0.0.0.255 area 0
exit
end
R3
enable
conf ter
interface f 0/0
ip addr 30.30.30.2 255.255.255.0
no shutdown
exit
interface f 0/1
ip addr 40.40.40.1 255.255.255.0
no shutdown
exit
interface loopback 0
ip addr 3.3.3.3 255.255.255.255
no shutdown
exit
router ospf 1
router-id 3.3.3.3
network 30.30.30.0 0.0.0.255 area 0
network 40.40.40.0 0.0.0.255 area 2
exit
end
R4
enable
conf ter
interface f 0/0
ip addr 40.40.40.2 255.255.255.0
no shutdown
exit
interface f 0/1
ip addr 50.50.50.1 255.255.255.0
no shutdown
exit
interface loopback 0
ip addr 4.4.4.4 255.255.255.255
no shutdown
exit
router ospf 1
router-id 4.4.4.4
network 40.40.40.0 0.0.0.255 area 2
network 50.50.50.0 0.0.0.255 area 2
exit
end
🎉
Test
On Any Router
show ip route
show ip ospf neighbor
Redistribute
Topology
Step by Step
R1
enable
conf ter
interface f 0/0
ip addr 10.1.3.2 255.255.255.0
no shutdown
exit
interface f 0/1
ip addr 10.1.1.1 255.255.255.0
no shutdown
exit
interface loopback 0
ip addr 110.1.1.1 255.255.255.255
no shutdown
exit
ip routing
ip route 10.1.3.0 255.255.255.0 FastEthernet0/0
ip route 10.1.1.0 255.255.255.0 FastEthernet0/1
ip route 10.1.2.0 255.255.255.0 FastEthernet0/1
ip route 10.1.4.0 255.255.255.0 FastEthernet0/1
end
R2
enable
conf ter
interface f 0/0
ip addr 10.1.1.2 255.255.255.0
no shutdown
exit
interface f 0/1
ip addr 10.1.2.1 255.255.255.0
no shutdown
exit
interface loopback 0
ip addr 120.1.1.1 255.255.255.255
no shutdown
exit
router ospf 1
router-id 120.1.1.1
network 10.1.2.0 0.0.0.255 area 0
network 10.1.4.0 0.0.0.255 area 0
redistribute static subnets
redistribute connected subnets
exit
ip routing
ip route 10.1.1.0 255.255.255.0 FastEthernet0/0
ip route 10.1.3.0 255.255.255.0 FastEthernet0/0
end
R3
enable
conf ter
interface f 0/0
ip addr 10.1.2.2 255.255.255.0
no shutdown
exit
interface f 0/1
ip addr 10.1.4.1 255.255.255.0
no shutdown
exit
interface loopback 0
ip addr 130.1.1.1 255.255.255.255
no shutdown
exit
router ospf 1
router-id 130.1.1.1
network 10.1.2.0 0.0.0.255 area 0
network 10.1.4.0 0.0.0.255 area 0
exit
end
PC1
ip 10.1.3.1/24 10.1.3.2
PC2
ip 10.1.4.2/24 10.1.4.1
🎉
Stub, Totally-Stubby and NSSA
Topology
Step by Step
Area 1 as Stub Area
First, we will config area1 as stub area
R1
enable
conf ter
interface f 0/0
ip addr 10.1.4.2 255.255.255.0
no shutdown
exit
interface f 0/1
ip addr 10.1.1.1 255.255.255.0
no shutdown
exit
interface loopback 0
ip addr 1.1.1.1 255.255.255.255
no shutdown
exit
router ospf 1
router-id 1.1.1.1
area 1 stub
network 10.1.1.0 0.0.0.255 area 1
network 10.1.4.0 0.0.0.255 area 1
exit
end
R2
enable
conf ter
interface f 0/0
ip addr 10.1.1.2 255.255.255.0
no shutdown
exit
interface f 0/1
ip addr 10.1.2.1 255.255.255.0
no shutdown
exit
interface loopback 0
ip addr 2.2.2.2 255.255.255.255
no shutdown
exit
router ospf 1
router-id 2.2.2.2
area 1 stub
network 10.1.1.0 0.0.0.255 area 1
network 10.1.2.0 0.0.0.255 area 0
exit
end
R3
enable
conf ter
interface f 0/0
ip addr 10.1.2.2 255.255.255.0
no shutdown
exit
interface f 0/1
ip addr 10.1.3.1 255.255.255.0
no shutdown
exit
interface loopback 0
ip addr 3.3.3.3 255.255.255.255
no shutdown
exit
router ospf 1
router-id 3.3.3.3
network 10.1.2.0 0.0.0.255 area 0
network 10.1.3.0 0.0.0.255 area 0
Test
On Any Router
show ip route
show ip ospf neighbor
show ip ospf database
exit
end
##### PC1
```cisco
ip 10.1.4.1/24 10.1.4.2
PC2
ip 10.1.3.2/24 10.1.3.1
Now you should check Route and LSDB.
show ip route
show ip ospf database
Area 1 as totally-stubby area
Then we will config area1 as totally-stubby area
R1
enable
conf ter
router ospf 1
area 1 stub no-summary
exit
end
R2
enable
conf ter
router ospf 1
area 1 stub no-summary
exit
end
Now you should check Route and LSDB on all routers.
show ip route
show ip ospf database
Area 1 as NSSA
Then we will config area1 as NSSA
R1
enable
conf ter
router ospf 1
no area 1 stub
area 1 nssa
exit
end
R2
enable
conf ter
router ospf 1
no area 1 stub
area 1 nssa
exit
end
Now you should check Route and LSDB on all routers.
show ip route
show ip ospf database
🎉
Route Summarization
Topology
Step by Step
R1
enable
conf ter
interface f 0/0
ip address 10.1.3.2 255.255.255.0
no shutdown
exit
interface f 0/1
ip address 10.1.4.2 255.255.255.0
no shutdown
exit
interface f 1/0
ip address 10.1.2.1 255.255.255.0
no shutdown
exit
interface loopback 0
ip address 1.1.1.1 255.255.255.255
no shutdown
exit
router ospf 1
router-id 1.1.1.1
network 10.1.2.0 0.0.0.255 area 1
network 10.1.3.0 0.0.0.255 area 1
network 10.1.4.0 0.0.0.255 area 1
exit
end
R2
enable
conf ter
interface f 0/0
ip address 10.1.2.2 255.255.255.0
no shutdown
exit
interface f 0/1
ip address 10.1.1.1 255.255.255.0
no shutdown
exit
interface loopback 0
ip address 2.2.2.2 255.255.255.255
no shutdown
exit
router ospf 1
router-id 2.2.2.2
network 10.1.1.0 0.0.0.255 area 0
network 10.1.2.0 0.0.0.255 area 1
exit
end
R3
enable
conf ter
interface f 0/0
ip address 10.1.1.2 255.255.255.0
no shutdown
exit
interface f 0/1
ip address 192.168.1.1 255.255.255.0
no shutdown
exit
interface f 1/0
ip address 192.168.2.1 255.255.255.0
no shutdown
exit
interface loopback 0
ip address 3.3.3.3 255.255.255.255
no shutdown
exit
router ospf 1
router-id 3.3.3.3
network 10.1.1.0 0.0.0.255 area 0
redistribute connected subnets
exit
ip routing
ip route 192.168.1.0 255.255.255.0 FastEthernet0/1
ip route 192.168.2.0 255.255.255.0 FastEthernet1/0
end
PC1
ip 192.168.1.2/24 192.168.1.1
PC2
ip 192.168.2.2/24 192.168.2.1
PC3
ip 10.1.3.1/24 10.1.3.2
PC4
ip 10.1.4.1/24 10.1.4.2
Now check LSDB and routing table using
show ip route
show ip ospf database
show ip ospf neighbor
we are adding route summarization to this network.
R2
note: This is a ABR, so use area [area-id] prefix mask to summarize route
conf ter
router ospf 1
area 1 range 10.1.0.0 255.255.248.0
end
R3
conf ter
router ospf 1
summary-address 192.168.0.0 255.255.252.0
endimage
Now check LSDB and routing table using
show ip route
show ip ospf database
show ip ospf neighbor
Mixed Types of Area
Topology
Step by Step
R1
enable
conf ter
interface f 0/0
ip addr 30.30.30.2 255.255.255.0
no shutdown
exit
interface f 0/1
ip addr 40.40.40.1 255.255.255.0
no shutdown
exit
interface loopback 0
ip addr 1.1.1.1 255.255.255.255
no shutdown
exit
router ospf 1
router-id 1.1.1.1
network 40.40.40.0 0.0.0.255 area 0
network 30.30.30.0 0.0.0.255 area 0
exit
end
R2
enable
conf ter
interface f 0/1
ip addr 50.50.50.2 255.255.255.0
no shutdown
exit
interface f 0/0
ip addr 60.60.60.1 255.255.255.0
no shutdown
exit
interface f 1/0
ip addr 90.90.90.2 255.255.255.0
no shutdown
exit
interface f 2/0
ip addr 100.100.100.1 255.255.255.0
no shutdown
exit
interface loopback 0
ip addr 2.2.2.2 255.255.255.255
no shutdown
exit
router ospf 1
router-id 2.2.2.2
network 50.50.50.0 0.0.0.255 area 0
network 60.60.60.0 0.0.0.255 area 0
network 90.90.90.0 0.0.0.255 area 3
network 100.100.100.0 0.0.0.255 area 3
area 3 virtual-link 9.9.9.9
exit
end
R3
enable
conf ter
interface f 1/0
ip addr 50.50.50.1 255.255.255.0
no shutdown
exit
interface f 0/1
ip addr 30.30.30.1 255.255.255.0
no shutdown
exit
interface f 0/0
ip addr 20.20.20.2 255.255.255.0
no shutdown
exit
interface loopback 0
ip addr 3.3.3.3 255.255.255.255
no shutdown
exit
router ospf 1
router-id 3.3.3.3
area 1 stub
network 50.50.50.0 0.0.0.255 area 0
network 30.30.30.0 0.0.0.255 area 0
network 20.20.20.0 0.0.0.255 area 1
exit
end
R4
enable
conf ter
interface f 0/0
ip addr 40.40.40.2 255.255.255.0
no shutdown
exit
interface f 0/1
ip addr 60.60.60.2 255.255.255.0
no shutdown
exit
interface f 1/0
ip addr 70.70.70.1 255.255.255.0
no shutdown
exit
interface f 2/0
ip addr 80.80.80.1 255.255.255.0
no shutdown
exit
interface loopback 0
ip addr 4.4.4.4 255.255.255.255
no shutdown
exit
router ospf 1
router-id 4.4.4.4
network 40.40.40.0 0.0.0.255 area 0
network 60.60.60.0 0.0.0.255 area 0
network 70.70.70.0 0.0.0.255 area 2
network 80.80.80.0 0.0.0.255 area 2
area 2 stub no-summary
exit
end
R5
enable
conf ter
interface f 1/0
ip addr 20.20.20.1 255.255.255.0
no shutdown
exit
interface f 0/0
ip addr 10.10.10.2 255.255.255.0
no shutdown
exit
interface loopback 0
ip addr 5.5.5.5 255.255.255.255
no shutdown
exit
router ospf 1
router-id 5.5.5.5
area 1 stub
network 10.10.10.0 0.0.0.255 area 1
network 20.20.20.0 0.0.0.255 area 1
exit
end
R6
enable
conf ter
interface f 0/0
ip addr 10.10.10.1 255.255.255.0
no shutdown
exit
interface loopback 0
ip addr 6.6.6.6 255.255.255.255
no shutdown
exit
router ospf 1
router-id 6.6.6.6
area 1 stub
network 10.10.10.0 0.0.0.255 area 1
exit
end
R7
enable
conf ter
interface f 0/0
ip addr 80.80.80.2 255.255.255.0
no shutdown
exit
interface loopback 0
ip addr 7.7.7.7 255.255.255.255
no shutdown
exit
router ospf 1
router-id 6.6.6.6
network 80.80.80.0 0.0.0.255 area 2
area 2 stub no-summary
exit
end
R8
enable
conf ter
interface f 0/1
ip addr 70.70.70.2 255.255.255.0
no shutdown
exit
interface loopback 0
ip addr 8.8.8.8 255.255.255.255
no shutdown
exit
router ospf 1
router-id 8.8.8.8
network 70.70.70.0 0.0.0.255 area 2
area 2 stub no-summary
exit
end
R9
enable
conf ter
interface f 0/0
ip addr 90.90.90.1 255.255.255.0
no shutdown
exit
interface f 0/1
ip addr 110.110.110.2 255.255.255.0
no shutdown
exit
interface loopback 0
ip addr 9.9.9.9 255.255.255.255
no shutdown
exit
router ospf 1
router-id 9.9.9.9
network 90.90.90.0 0.0.0.255 area 3
network 110.110.110.0 0.0.0.255 area 4
area 3 virtual-link 2.2.2.2
area 4 nssa
exit
end
R10
enable
conf ter
interface f 0/0
ip addr 100.100.100.2 255.255.255.0
no shutdown
exit
interface f 0/1
ip addr 140.140.140.1 255.255.255.0
no shutdown
exit
interface loopback 0
ip addr 10.10.10.10 255.255.255.255
no shutdown
exit
router ospf 1
redistribute rip subnets
router-id 10.10.10.10
network 100.100.100.0 0.0.0.255 area 3
exit
router rip
version 2
redistribute ospf 1 metric 1
network 140.140.140.0
exit
end
R11
enable
conf ter
interface f 0/0
ip addr 120.120.120.1 255.255.255.0
no shutdown
exit
interface f 0/1
ip addr 130.130.130.2 255.255.255.0
no shutdown
exit
interface loopback 0
ip addr 11.11.11.11 255.255.255.255
no shutdown
exit
router ospf 1
redistribute rip subnets
router-id 11.11.11.11
network 120.120.120.0 0.0.0.255 area 4
area 4 nssa
exit
router rip
version 2
redistribute ospf 1 metric 1
network 130.130.130.0
exit
end
R12
enable
conf ter
interface f 0/1
ip addr 110.110.110.1 255.255.255.0
no shutdown
exit
interface f 0/0
ip addr 120.120.120.2 255.255.255.0
no shutdown
exit
interface loopback 0
ip addr 12.12.12.12 255.255.255.255
no shutdown
exit
router ospf 1
router-id 12.12.12.12
network 110.110.110.0 0.0.0.255 area 4
network 120.120.120.0 0.0.0.255 area 4
area 4 nssa
exit
end
R13
enable
conf ter
interface f 0/0
ip addr 130.130.130.1 255.255.255.0
no shutdown
exit
interface loopback 0
ip addr 13.13.13.13 255.255.255.255
no shutdown
exit
router rip
version 2
network 130.130.130.0
exit
end
R14
enable
conf ter
interface f 0/0
ip addr 140.140.140.2 255.255.255.0
no shutdown
exit
interface loopback 0
ip addr 14.14.14.14 255.255.255.255
no shutdown
exit
router rip
version 2
network 140.140.140.0
exit
end
🎉
Reference
https://www.geeksforgeeks.org/configuring-ospf-route-summarization-in-cisco/ http://www.cisco.com/en/US/docs/ios-xml/ios/iproute_ospf/command/ospf-s1.html#wp4241563273