REPORTER two In this example is an area border, rather.
So we have to configure interfaces in both Area one and Area zero.
Rotor three is also an area border router.
It has an interface, an area zero as well as an interface in area two.
We've been told to configure OSPF using interface commands.
So on raw two three we have this interface which needs to be in Area two.
This interface needs to be an Area zero and we'll configure the loopback interface in Area zero as well.
So router OSPF one, that's all we need to do.
Now, what we need to do in this example is go on to interfaces because we've been told to enable OSPF
using interface commands.
IP OSPF Process one area zero interface gigabit zero one IP OSPF Area zero interface gigabit zero zero.
In this case, interface gigabit is zero zero is going to be in area two, actually not area one.
So let's confirm that I did that right.
This interface needs to be in Area Zero.
This interface needs to be in area two.
That's good.
And this interface needs to be an area zero.
We can confirm that.
We've done that right by using the show IP Interface Command.
In the real world you may want to use show IP OSPF interface brief packet tracer doesn't support that
command, it only supports the detailed command rather than brief.
We can see that the loopback is in area zero gigabit is zero one, is in area zero and gigabit is zero
zero.
Is now in area two.
So that looks good.
Show ip ospf neighbor.
We have a neighbor relationship established rather to show IP route.
We see both intra area OSPF routes.
As well as into area OSPF routes.
This route came from area one, whereas this route originated in area zero.
Yes.
A another inter area ospf route.
So ping ten 111.
That works.
Ping 1.1.1.1.
That also works.
So we have connectivity now between router three and.
Root of two and root of one on router one show IP root we see an inter area root for the loopback of
router three and we also see inter area roots for ten 1 to 0 as well as ten 130.
So can we ping the loopback of router two?
Yes, we can.
What about router three?
Yes, we can.
What about ten?
One, two, one.
Yes, we can.
Ten.
One, two, two.
Yes, we can.
The network is working as expected.
So the last router to configure is router four.
That's a fairly easy one.
On rather for we need to enable all interfaces with a single network command.
So on right of for rather ospf one network.
And we can simply do this to enable OSPF on all interfaces in area two.
So what should happen is we should see a neighbor relationship established to router three.
It may take it a while to form.
In the meantime, we can check that OSPF is enabled.
As you can see there, the relationship has just come up.
But she has the output of show IP protocols.
We running OSPF and process ID one.
We have enabled OSPF on all interfaces using this command and all interfaces belong to area to show
IP route.
Here we see an interior route from area one into area routes from area zero.
Area zero into area routes.
There are no OSPF intra area routes because on router three, the loopback and this interface are in
area zero.
There are no other interfaces in area two on router three.
So ping 1.1.1 that works.
Can we trace to router one?
Yes, we can ping the loopback of router two.
That works.
Loopback of router three that works.
So after this point we've successfully configured OSPF on all our routers router foes OSPF database
only shows information for area two.
There are two routers in Area two.
These are LSA Type one advertisements.
There is one designated router in area two and that designated router is router three.
These are LSA type three's.
In other words, summary ALA says these networks originated in other areas and we can see that.
Over here by looking at inter area in the routing table.
So these routes came from a different area to area to.
On Router three.
Show IP OSPF database router three has interfaces in area zero as well as area two.
So it sees two routers in area zero one designated router in area zero.
Designated router is rather two.
It sees summary losses, type three losses in Area zero.
These networks originated from other areas.
As an example, this network originated from Area one.
This network originated from Area two.
Router three also has interfaces in area two, so it sees two riders and Area two, one designated writer
in Area two and these summary or LSA Type three networks in Area two routers in areas have the same
database.
So the database of router three and router four are the same four.
Area two database for router two and router three are the same for area zero.
Database for router one and router two are the same for area one.
So going back to router one, show IP OSPF database.
Rather one only has interfaces in area one, so we only see area one.
Two roads in area one one designated rotor.
These routes originated from other areas.
Show IP route shows us that again.
Notice this loopback.
The loopback of router four is an entire area route.
Originated in another area, but rather one can still ping that loopback.
We've successfully configured this network with OSPF in multiple areas.
How did you get on?
Were you able to do this yourself?