ICND1 Labs

Lab 4-3: Implementing OSPF

Visual Topology

Command Line

Command Description
Erase startup-config or Write erase Removes the startup-configuration from NVram
Hostname Defines a system device name shown in the prompt
interface name Enters interface configuration mode
ip address ip address mask Assigns an IP address to an interface
Network {address [wildcard mask]} area id Defines which interfaces are part of the OSPF routing process
router ospf process id Enters the OSPF configuration mode and defines the locally significant process id
show ip ospf interface Displays interface information related to OSPF
show ip ospf neighbor Shows the output of the OSPF adjacency table
show ip route Shows the contents of the IPv4 routing table
[no] shutdown Disables or enables an interface

This lab exercise requires two students to work together to complete the tasks. Use the
visual topology diagram to ascertain the correct IP addressing plan for your PC, Router and

Physical Topology Diagram

  • Task 1: Setting-up a Routed WAN connection.
  • Task 2: Configuring OSPF.

Lab 4-3: Implementing OSPF

Task 1: Setting-up a Routed WAN connection.

Step 1: Access the CLI on both your switch and router.

Step 2: Clear down their current configuration and reload the devices using the erase startup-config and reload commands. Make sure you do this on both the router and the switch.

If the system indicates that the system configuration has been modified and do you want to save ? Answer no

Confirm the reload.

Step 3: The devices have been set back to factory defaults (well almost) ignore and abort the setup dialogue options.

Using the information in the visual topology diagram, setup the correct IP addresses and hostnames on all 3 devices.

Switch#conf t
Switch(config)#hostname SW1
SW1(config)#interface vlan 1
SW1(config-if)#ip address
SW1(config-if)#no shut 
Router#conf t
Router(config)#hostname R1
R1(config)#interface fa0/0 
R1(config-if)#ip address
R1(config-if)#no shut
R1(config-if)#interface fa0/1
R1(config-if)#ip address
R1(config-if)#no shut

Check that the interfaces are up/up, troubleshoot any discrepancies.

Remember to set a static IP address on the PC interface and check connectivity between the PC and its default router.

Task 2: Configuring OSPF.

By default routers do not run any dynamic routing protocols, however routing between IPv4 locally connected interfaces is enabled by default.

Step 1: Execute the relevant show command to display the contents of the routing table.

The table displays only two connected subnets and therefore this router only has paths for subnets and

Step 2: Enter OSPF configuration mode and use a process id of 1.

Rx(config)#Router ospf 1

Step 3: Enable both interfaces for ospf and place them in the backbone area 0

R1 only.....
R1(config-router)#network area 0
R1(config-router)#network area 0
R2 only.....
R2(config-router)#network area 0
R2(config-router)#network area 0

Step 4: Check the contents of the routing table. Do you see any additional entries?

Step 5: Check connectivity by pinging the IP address of the other router’s fa0/0 interface.

Step 6: Save the configuration on both the switch and router.

Lab Answer Keys:

[Locker] The locker [id=4139] doesn't exist or the default lockers were deleted.

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