In this LAB, I will show you the difference between Type1 and Type2 when you import RIP to OSPF. To be able to show you the difference, we must remove the import route command that we have done on R3 to import RIP into OSPF.

Now the OSPF routers cannot see the network 5.5.5.0/24 anymore, and to be sure let’s check the routing table of R1.

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Indeed, R1 does not see 5.5.5.0/24 in his routing table anymore.

Now, what is Type1 and Type 2 that I am referring to. If you go again to the import route command and you make a “?” (question mark), you can see that you have “Type”. This can be Type 1 or Type 2. Let me show you that.

If you import RIP into OSPF as type 1, then the route will add the cost of the links inside the OSPF network to the cost of the external link. That means that the cost will not be the same inside the OSPF network.

While if you import RIP into OSPF as type 2, then the route will have the cost of the external link no matter how many links it passes through in the internal OSPF network.

So generally, a type1 route will have a higher cost than a type 2 route and routers in the OSPF network will prefer the type 1 route.

Let me show you that. I will import the RIP into OSPF as type 2. The cost then should not change. Let’s see.

I will check on R1 an R4 what will be the cost for the entry 5.5.5.0/24 in their routing table.

Both R1 and R4 have the same cost in the routing entry of 5.5.5.0/24 which is 1 even that R4 is far from R1. And that’s because we have imported RIP into OSPF as type 2, so the cost doesn’t change.

Let’s import now RIP into OSPF as type 1 and see if the cost will change between R1 and R4.

I will remove the old route import and make the new one as type 1 now.

The command has been entered on R3. Let’s check the routing tables of R1 and R4 and see what the result will be.

Look now!!!! R1 has 5.5.5.0/24 route with a cost of 2 and R4 has 5.5.5.0/24 route with a cost of 3. So, the cost has been changed because R4 is far from R1, and in case we had a router even far than R4 then you would see that the cost would increase.

That’s all what I needed to show you in this LAB and in this chapter, I hope you enjoyed it and see you in the upcoming one.

P.S: please keep the LAB operational because we need it for the upcoming chapter.

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