OSPF Standard and Backbone Area

In this article series we will concentrate on OSPF Area Types and their configuration examples on Packet Tracer.

You can DOWNLOAD the Packet Tracer example with .pkt format HERE.

As you know from the previous posts, OSPF has 6 different areas. These areas are:

– Backbone Area
– Standard (Normal) Area
– Stub Area
– Totally-Stub Area
– Not-So-Stubby Area (NSSA)
– Totally Not-So-Stubby Area

In this first post, we will focus on Backbone Area and Standard (Normal) Area. Beside this, we will see the configuration of virtual-link on OSPF. What was the virtual-link? It was the link that used to connect the normal areas to the backbone area, if they are not connected directly to the backbone area. Remember, in OSPF, there was a rule. All areas must be connected to the backbone area, Area 0. If they are not, they can temporarily connect to the backbone via virtual-links.

OSPF Backbone Area and Standard Area with Accepted LSAs
Backbone Area is also a Normal Area but it is Area 0.

Normal Areas accept the Summary LSAs from other Areas (Type 3 and Type 4 LSAs). They accept also the External LSAs (Type 5 LSAs). Type 1 and Type 2 LSA are already accepted inside area.

We talked about theorical too much. This post aims to show you the configuration of this areas and as you know, doing the configuration is the most effective way of learning network protocols.

Our topology will be like below fort he first example.

OSPF Backbone Area, Standard Area and
Virtual-Link Example Topology
As you can see, in this topology, there are Backbone Area (Area 0) and three standard (normal) areas (Area 1, Area 2, Area3).

Firstly let’s configure the IP Addresses on all routers:

Router1

Router1>enable
Router1# configure terminal
Router1(config)# interface GigabitEthernet0/0
Router1(config-if)# ip address 10.1.0.1 255.255.255.0
Router1(config-if)# no shutdown
Router1(config-if)# exit
Router1(config)# interface GigabitEthernet0/1
Router1(config-if)# ip address 10.2.0.1 255.255.255.0
Router1(config-if)# no shutdown
Router1(config-if)# end
Router1# copy running-config startup-config

Router2

Router2>enable
Router2# configure terminal
Router2(config)# interface GigabitEthernet0/0
Router2(config-if)# ip address 10.1.0.2 255.255.255.0
Router2(config-if)# no shutdown
Router2(config-if)# exit
Router2(config)# interface GigabitEthernet0/1
Router2(config-if)# ip address 10.3.0.1 255.255.255.0
Router2(config-if)# no shutdown
Router2(config-if)# end
Router2# copy running-config startup-config

Router3

Router3>enable
Router3# configure terminal
Router3(config)# interface GigabitEthernet0/0
Router3(config-if)# ip address 10.2.0.2 255.255.255.0
Router3(config-if)# no shutdown
Router3(config-if)# exit
Router3# copy running-config startup-config

Router4

Router4>enable
Router4# configure terminal
Router4(config)# interface GigabitEthernet0/0
Router4(config-if)# ip address 10.4.0.1 255.255.255.0
Router4(config-if)# no shutdown
Router4(config-if)# exit
Router4(config)# interface GigabitEthernet0/1
Router4(config-if)# ip address 10.3.0.2 255.255.255.0
Router4(config-if)# no shutdown
Router4(config-if)# end
Router4# copy running-config startup-config

Router5

Router5>enable
Router5# configure terminal
Router5(config)# interface GigabitEthernet0/0
Router5(config-if)# ip address 10.4.0.2 255.255.255.0
Router5(config-if)# no shutdown
Router5(config-if)# exit
Router5(config)# interface GigabitEthernet0/1
Router5(config-if)# ip address 10.5.0.1 255.255.255.0
Router5(config-if)# no shutdown
Router5(config-if)# end
Router5# copy running-config startup-config

Router6

Router6>enable
Router6# configure terminal
Router6(config)# interface GigabitEthernet0/1
Router6(config-if)# ip address 10.5.0.2 255.255.255.0
Router6(config-if)# no shutdown
Router6(config-if)# end
Router6# copy running-config startup-config

After this basic interface configurations, let’s configure the OSPF on all routers. Here, OSPF process number will be 1 and the Routerx’s router ID will be x.x.x.x. Beside this, all the connected areas will be configured.