Lab 6 - OSPF Multi-Area Network

Prerequisites: CCNP level skills.

In the next few labs I am going to use the following topology.

Topology

Pic. 1 - OSPF Multi-Area Topology.

Icons designed by: Andrzej Szoblik - http://www.newo.pl

Workflow

1. Get familiar with the topology and the 'Task List'.
2. Answer the questions.
3. Enable IP addresses as per the topology diagram (pic. 1).
4. Check layer 3 reachability between all routers (point to point reachability since there is no OSPF enabled yet).
5. Enable OSPF as per topology diagram (pic. 1) using the Task List below.
6. Ensure full reachability between all IP addresses in the network presented (pic. 1).

Task List

• All loopback addresses should be advertised with their configured network mask (/24).
• All interfaces of R3 must belong to the backbone area.
• Loopback0 interfaces of R1 and R2 must belong to the area 0.
• F1/0 interfaces of R1 and R2 must belong the the area 1. Area 1 should be a normal area in this lab.
• R1 should be the DR, and R2 should be the BDR on the Ethernet Segment (10.1.123.0/24).
• All interfaces of R4 should operate in the area 1. The Loopback addresses should be advertised with their configured network mask.

Questions

1. What are the reasons to use multi-area rather than single area OSPF design?
2. What are the OSPF router types
3. What is ABR and its role?
4. What is ASBR and its role?
5. What are the types of LSAs and what they describe?
6. What are the OSPF area types and which LSAs do they maintain?

Video Note - The answers.
http://www.youtube.com/watch?v=8u6-_mkc0-4

Lab Solution

R1 Configuration:

!

interface Loopback0
 ip address 172.16.101.1 255.255.255.0
 ip ospf network point-to-point
!

interface FastEthernet1
 ip address 10.1.124.1
 ip ospf priority 20
!

interface Serial0/1
 ip address 10.1.13.1 255.255.255.0
 serial restart-delay 0

!

router ospf 1
 router-id 1.1.1.1
 log-adjacency-changes
 network 10.1.13.1 0.0.0.0 area 0
 network 10.1.124.1 0.0.0.0 area 1
 network 172.16.101.1 0.0.0.0 area 0
!

R2 Configuration:

!

interface Loopback0
 ip address 172.16.102.2 255.255.255.0
 ip ospf network point-to-point

!

interface FastEthernet1/0
 ip address 10.1.124.2 255.255.255.0
 ip ospf priority 10
!

interface Serial0/2
 ip address 10.1.23.2 255.255.255.0
 serial restart-delay 0

!

router ospf 1
 router-id 2.2.2.2
 log-adjacency-changes
 network 10.1.23.2 0.0.0.0 area 0
 network 10.1.124.2 0.0.0.0 area 1
 network 172.16.102.2 0.0.0.0 area 0
!

R3 Configuration:

!

interface Loopback0
 ip address 172.16.103.3 255.255.255.0
 ip ospf network point-to-point
!

interface Loopback1
 ip address 172.16.133.3 255.255.255.0
 ip ospf network point-to-point
!

interface Serial0/1
 ip address 10.1.13.3 255.255.255.0
 serial restart-delay 0

!

interface Serial0/2
 ip address 10.1.23.3 255.255.255.0
!

router ospf 1
 router-id 3.3.3.3
 log-adjacency-changes
 network 0.0.0.0 255.255.255.255 area 0
!

R4 Configuration:

!

interface Loopback0
 ip address 172.16.104.4 255.255.255.0
 ip ospf network point-to-point
!

interface Loopback1
 ip address 172.16.144.4 255.255.255.0
 ip ospf network point-to-point
!

interface FastEthernet1/0
 ip address 10.1.124.4 255.255.255.0
!

router ospf 1
 router-id 4.4.4.4
 log-adjacency-changes
 network 0.0.0.0 255.255.255.255 area 1

Verification

Pic. 1

Pic. 2

Pic.3

Pic. 4