I have this LAB scenario. I have already configured OSPF on all routers and I have configured RIP between R3 and R4 and made the route import.

R1 should now see the route of 192.168.34.0/24 as LSA Type 5 external route from OSPF and should also see the route of 192.168.23.0/24 as a LSA Type 3 summary route from OSPF (inter-area).

Let’s check that from R1.

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In the routing table of R1 they are there. I should like to see them also in the LSDB table so I can see the LSA types.

You can see on the LSDB table, it shows the network 192.168.23.0 as an LSA Type 3 Summary network and then network 192.168.34.0 as an LSA Type 5 External.

Excellent for now!!!!

What I wish to do, is to make the area 1 as a stub area. Remember, in the stub area the LSA Type 5 external will be blocked, that means we shouldn’t see it in the LSDB once we make the area 1 stub (LSA type 3 summary network will still show up).

Let’s do the configuration.

As simple as that. I have made now area 1 as a stub area. Let’s check if the LSA type 5 external is still showing on R1.

You can see clearly that the LSA type 5 external has disappeared on the LSDB once I made area 1 as a stub area.

Let’ see now R1 routing table to check how he will be able to reach the network 192.168.34.0/24.

A default route has been inserted on OSPF to allow the R1 to reach the network 192.168.34.0.

You can see also that 192.168.23.0 which is an inter-area is still there.

Let’s ping from R1 to 192.168.34.4 to see if we can reach to that network.

We can with success. R1 used the default route to reach to the network in RIP.

Let’s remove the stub area now so I can do the upcoming LAB. Once done, please leave the LAB open.

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