[AUDIO LOG]
So finally, let's finish up with the Total NSSA.
Now, the Total NSSA is much like the Total Stub in that, again,
we're just going to be filtering out the additional Type 3
LSAs that are normally coming into the area.
So from that perspective, it's about the same.
Now, one thing that's going to change between the normal NSSA
is that default-information-originate
we were doing is now going to be overridden by the no-summary,
which makes it the Total NSSA.
And it's going to send in a Type 3 LSA.
So let's jump in and get started.
We'll start looking at the routing table on router 5
and then we'll convert this to a Total NSSA.
So remember that router 5 is inside the NSSA,
so when we do our show ip router ospf,
what we're really looking for is the fact that we're getting
all of these O IA routes.
Also as a reminder, notice our default is coming
in as an N2, so a Type 7.
Now let's convert this to a Total NSSA.
We'll start on router 1.
So we're going to router ospf 1.
And again, for area 100 after our nssa,
we simply add no-summary just like we do for the Stub.
And this makes it a Total NSSA.
We'll commit that change, and let's go look at router 5.
So once again, if we look at the routing table on router 5,
there's two things to note here.
First, we're still getting all the Type 3 LSAs,
but if we look at their next hops,
they're all headed towards router 4, which
would be down towards router 3.
So these are the O IA routes coming in from router 3
because we haven't converted router 3 to Total NSSA yet.
Also note that the default is now an O IA or a type 3 LSA.
Now, let's go ahead and convert router as well.
Again, router 3 is the same configuration
so we'll simply paste it in, and we'll
go back to router 5 to verify.
We do our show ip router ospf again.
We'll see that all we have are the O routes which
are internal to this area, the N2s, which are of course coming
from router 2, and our EIGRP environment,
and then we have our Type 3 LSA coming in as our default.
Just as a quick note here, the reason
the LSA type changes on the default
is we can no longer allow you to follow an external default
route like we could in the normal NSSA.
That's because we're actually hiding OSPF information here.
You don't have all of the internal OSPF routes.
And because of that, it really needs
to force you to default route to the ABR.
So this difference in Lisa type between a normal NSSA
doing a default-information-originate
and the Total NSSA doing the Type 3,
this is absolutely done to prevent loops and inadvertently
following a default out of the OSPF environment
when in fact the route is internal to OSPF.
Now there is sort of one other minor issue
we should address here just because it's another NSSA
option we haven't looked at.
Let's go over to router 1 and configure it to redistribute
an interface into OSPF.
So here we'll make an interface loopback 100.
We'll simply make that IP address 101.1.1.1/24.
We'll bring that interface up.
We're going to route out of ospf 1.
And we will say to redistribute connected routes, which
will bring in that loopback.
Commit our changes.
Now, we should see this route on router 5,
which is sort of interesting.
Let's go check it out.
Notice if I look at my routing table again,
now I've got that 100.1.1.0/24.
Now there's nothing necessarily wrong
with that except we're already getting a default. In fact,
we're getting a default from router 1.
So there's no point in following a specific route towards router
1 when we already have a default.
So if we don't want the ASBR that is also the ABR
to redistribute this into the NSSA itself,
we have to actually turn that off.
Let's go back over to router 1, and what
we need to do is on the end of our area 100 nssa no-summary,
we need to add no-redistribution.
We'll commit those changes.
And let's go back to router 5.
If we do our show ip router ospf,
notice that that 100 network is now
gone and we would just follow the default.
And just to make sure everything's working,
we should be able to ping that address, we have success,
so this is just going to follow the default to get there.
So in this video, we saw how to configure the Total NSSA.
And as you probably noticed, it's
configured in exactly the same fashion
as we configure the Total Stub.
We simply add no-summary to the end of the either NSSA or Stub
command.
We also took a look at what the no-redistribution command does
to prevent an ASBR that is also an ABR from sending
those routes into the NSSA.
This of course, is most useful when
you're doing the default-originate
or when you're doing the Total NSSA.
I hope this has been informative for you
and I'd like to thank you for viewing.