OSPF Configuration 3​

Topology

Tasks:

A mid-sized company operates a network with multiple routers interconnecting their main office, data center, and branch locations. To ensure efficient routing and scalability, the company wants to configure OSPF in a single area (Area 0) across all routers. R3 and R4 are already configured and in accessible. You have been tasked with implementing OSPF on R1 and R2 ensuring full connectivity between all devices. 

  1. Configure the router ID of R1 and R2 as 1.1.1.1 and 2.2.2.2 respectively.
  2. Configure OSPF Area 0 with process ID 10 on R1 and R2 to establish adjacencies with the neighbors. Do not use the network command under the OSPF process.
  3. Configure R1 and R2 to advertise their loopback0 address into area 0 without using network command under OSPF process.
  4. Configure the network type of link between R1 and R2 so that they can't add any more OSPF routers.

Solution:

Task 1: Configure the router ID of R1 and R2 as 1.1.1.1 and 2.2.2.2 respectively.

The router ID uniquely identifies each router in the OSPF process.

On R1:

R1(config)# router ospf 10
R1(config-router)# router-id 1.1.1.1
R1(config-router)# exit

On R2:

R2(config)# router ospf 10
R2(config-router)# router-id 2.2.2.2
R2(config-router)# exit

The router ospf 10 command starts the OSPF process with process ID 10. The router-id command is used to manually assign the router ID.

 

Task 2: Configure OSPF Area 0 with process ID 10 on R1 and R2 to establish adjacencies with the neighbors. Do not use the network command under the OSPF process.

Instead of the network command, ip ospf area command can be used under each interface of R1 and R2.

On R1:

R1(config)# interface g0/0
R1(config-if)# ip ospf 10 area 0
R1(config-if)# interface g0/1
R1(config-if)# ip ospf 10 area 0
R1(config-if)# exit

On R2:

R2(config)# interface g0/0
R2(config-if)# ip ospf 10 area 0
R2(config-if)# interface g0/1
R2(config-if)# ip ospf 10 area 0
R2(config-if)# exit

The ip ospf 10 area 0 command directly associates the interface with the OSPF process and places it in Area 0.

 

Task 3: Configure R1 and R2 to advertise their loopback0 address into area 0 without using network command under OSPF process.

We need to use  ip ospf 10 area 0 command here as well.

On R1:

R1(config)# interface loopback0
R1(config-if)# ip ospf 10 area 0
R1(config-if)# exit

On R2:

R2(config)# interface loopback0
R2(config-if)# ip ospf 10 area 0
R2(config-if)# exit

By applying ip ospf 10 area 0 directly on the loopback interfaces, they are advertised into OSPF.

 

Task 4: Configure the network type of link between R1 and R2 so that they can't add any more OSPF routers.

To ensure that no other OSPF routers can join the network, we need to set the OSPF network type on the link between R1 and R2 to point-to-point.

On R1:

R1(config)# interface g0/0
R1(config-if)# ip ospf network point-to-point
R1(config-if)# exit

On R2:

R2(config)# interface g0/0
R2(config-if)# ip ospf network point-to-point
R2(config-if)# exit

A point-to-point network type restricts the addition of other OSPF routers.

Now save the configuration.

R1(config-if)# end
R1# write memory

R2(config-if)# end
R2# write memory

 

Packet Tracer File

Clicking this button will begin the download of a ZIP file. Inside the ZIP file, you'll find a Packet Tracer Activity (.pka) file, which will automatically track your progress as you configure the network.

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