The objective of this lab exercise is for you to learn and understand how to enable OSPF using more than one Area.
Enabling Multi-Area OSPF is a fundamental skill. When configuring Multi-Area OSPF, it is imperative to remember that all Areas must be connected to the OSPF backbone area, which is area 0. As a Cisco engineer, as well as in the Cisco CCNA exam, you will be expected to know how to enable Multi-Area OSPF.
This lab is suitable for ICND2 and CCNA certification exam preparation.
This lab has a difficulty rating of 8/10.
When you are ready for your certification exam, you should complete this lab in no more than 30 minutes.
Please use the following topology to complete this lab exercise:
Configure hostnames on R1 and R2 as illustrated in the topology.
Enable the IP addressing scheme as illustrated. The .1 addresses on either end of R1 and R2 are for Loopback0, which makes it easy to test the commands without having to add switches.
Configure area 0 (the backbone area) between R1 and R2 FastEthernet interfaces.
Enable OSPF in area 5 for the network attached to Loopback0 on R1. Enable OSPF in Area 10 for the network attached to Loopback0 attached to R2.
Issue some show commands to check that your configurations have worked.
Configuration and Verification
For reference information on configuring hostnames, please refer to earlier labs.
For reference information on configuring IP addresses, please refer to earlier labs.
R1(config-if)#router ospf 1 R1(config-router)#network 192.168.1.0 0.0.0.3 area 0 R2(config)#router ospf 1 R2(config-router)#net 192.168.1.0 0.0.0.3 area 0 *Mar 1 00:04:49.211: %OSPF-5-ADJCHG: Process 1, Nbr 10.1.1.1 on FastEthernet0/0 from LOADING to FULL, Loading Done
R1(config-router)#router ospf 1 R1(config-router)#net 10.1.1.0 0.0.0.255 area 5 R2(config-router)#router ospf 1 R2(config-router)#network 172.16.1.0 0.0.0.255 area 10
R1#show ip route ospf 172.16.0.0/32 is subnetted, 1 subnets O IA 172.16.1.1 [110/11] via 192.168.1.2, 00:02:09, FastEthernet0/0 R2#show ip route ospf 10.0.0.0/32 is subnetted, 1 subnets O IA 10.1.1.1 [110/11] via 192.168.1.1, 00:03:03, FastEthernet0/0 R1#show ip ospf database OSPF Router with ID (10.1.1.1) (Process ID 1) Router Link States (Area 0) Link ID ADV Router Age Seq# Checksum Link count 10.1.1.1 10.1.1.1 385 0x80000003 0x006DC7 1 172.16.1.1 172.16.1.1 319 0x80000003 0x00547C 1 Net Link States (Area 0) Link ID ADV Router Age Seq# Checksum 192.168.1.2 172.16.1.1 576 0x80000001 0x00FE47 Summary Net Link States (Area 0) Link ID ADV Router Age Seq# Checksum 10.1.1.1 10.1.1.1 381 0x80000001 0x0080A1 172.16.1.1 172.16.1.1 315 0x80000001 0x005965 Router Link States (Area 5) Link ID ADV Router Age Seq# Checksum Link count 10.1.1.1 10.1.1.1 385 0x80000001 0x004CBD 1 Summary Net Link States (Area 5) Link ID ADV Router Age Seq# Checksum 172.16.1.1 10.1.1.1 316 0x80000001 0x00ED78 192.168.1.0 10.1.1.1 389 0x80000001 0x00AF0F R1#
NOTE: Understanding the information printed in the OSPF database is key to understanding the operation of OSPF. The show ip ospf database command shows the router ID of the router this command is issued on, as well as the locally significant OSPF process ID that has been enabled on the router. It also shows the different types of OSPF LSAs and the routes associated with those LSA types, as well as the OSPF Areas. In addition, each link ID listed in the OSPF database is identified by the originator of the LSA under the column ADV Router.