[AUDIO LOGO]
So now that we have IS-IS up and running in Area 100
acting our backbone area because we configured everything
as level-2, well, now, let's go ahead and configure Area 100.
Now, we are going to configure Area 100 just a little
bit differently.
So let's go ahead and bring up the topology,
take a look at it, and talk about what
we're going to configure just a little differently.
And then, of course, we're going to jump into the command line
and get IS-IS up and running.
So let's take a look at that topology.
So again.
In this video, we're going to be configuring
Area 10, which means we're just going to be configuring three
routers.
We're going to configure router-2, router-4,
and of course, router-5.
Now, what's going to be a little bit
different about this configuration is
although this multi-access network here will, of course,
still be a LAN network, what's going to change
is we're going to configure this as level-1.
We don't need level-2 here because this isn't necessarily
part of the backbone.
Now, we will have to configure router-2 as a level-1/level-2
because it's going to need to have level-2 like this in order
to ultimately connect in our Area 30 up here.
So router-2, at least for now, will be level-1, level-2,
but this LAN segment here between R2, R4, and R5,
we're going to start off configuring it, as we said,
just as level-1.
So with all of this in mind, let's jump
into the command line.
We'll go ahead and start on router-2.
So this will be much the same configuration
we've already looked at.
So again, we just turn on IS-IS.
We'll set our network number.
Again, it's going to be 49.
Now, this is going to be Area 10.
So this is going to be 0010 now.
And then, of course, we'll set this up to be system-ID-2.
So that takes care of our net number.
We go into our address family once again.
Set our router-ID, configure our metric-style,
going to our loopback interface, turn on our address family,
and then we'll start with our gigabits.
So we'll start with gigabit-0000.
This one is going to be level-2 because this is the interface
going over towards router-1.
It's also point-to-point.
And we'll enable our address family.
Gig-1, this one is going to be circuit-type level-1.
This is that multi-access segment,
that also means it doesn't get point-to-point.
So now, all we have to do is enable the address family.
Gigabit-2, this is going up to router-9.
This is also going to be level-2 because it's
going into a different area, also, point-to-point.
And we enable the address family.
Commit the changes.
Let's exit configuration.
And let's do some verification.
Let's do a show IS-IS protocol.
The main thing to look at here is the default level.
Notice that this is a level-1, 2 router because that
is the default. And that's good because,
again, that's what we need router-2 to be.
It's going to be level-1 down towards router-5 and router-4,
but it's level-2 going over towards router-1
and up towards router-9.
Let's also verify that our neighborships have come up.
At this point, we're only expecting a neighborship
to router-1, which we do have.
We see, of course, that it's out our gigabit-0000 interface that
is point-to-point and that it is a level-2 connection.
So, so far, this is looking good.
We can also verify that we have some routes.
We should, at this point, have all of the routes
from Area 100, and we can see here that we do.
Once again, at this point, they're all level-2,
and that's OK.
That's what we should have at this point.
So, so far, router-2 is looking good.
Let's go ahead and jump over and configure router-4.
Once again, almost the same configuration here.
Again, the net number is going to be different, but other
than that, it's pretty much the same.
Set our router-ID, metric-style.
We'll enable our address family under our loopback.
We'll set the circuit-type on gigabit-0000 to be level-2
since, again, that goes over towards router-3, also makes it
point-to-point.
And we'll enable our address family.
Interface gigabit-0001, this is going
to be a circuit-type level-1 because again, this
is that multi-access network.
That also means it does not get set to point-to-point.
And all we have to do is activate our address family.
Commit our changes and exit config.
So once again, let's do some verification.
We'll do our show IS-IS protocol.
And again, this is a level-1-2 router.
That's what it needs to be because again, it's connected
at level-2 over to router-3.
And we can come down here and see
that we are, in fact, running it on the correct interfaces.
We do a show IP route for IS-IS routes.
We can see here that we have mostly level-2 routes.
But notice, we do have, at this point,
at least one level-1 route.
This is the route coming from router-2's loopback.
Because at the moment, if we do a show ISS neighbor,
we can see that our neighborship to router-2
is actually a level-1.
So that explains why we're getting a level-1 route
on the connection from router-2.
And again, this is exactly what we intended.
We can also see this in the database.
If we do a show IS-IS database, this
means we're now going to have two databases.
Here, we have a level-1 database.
And here, we have our level-2 database.
So finally, let's go configure router-5.
Again, this is IOS XE.
So it's going to be just a little bit different but mostly
the same.
Again, we go into our IS-IS process.
We'll set our network number.
This one will go ahead and set the is-type because router-5
only has to run level-1.
We'll set our router-ID.
We'll set our metric-style.
And then we'll go to our interfaces.
We can see our neighborships have already come up,
but we'll just go ahead and hard-code the circuit-type
anyway just so we know that it's level-1.
Exit out of configuration.
And let's do some verification.
Once again, we'll do a show IS-IS neighbor
even though as we've already seen,
router-2 and router-4 already came up.
So we see that those are good.
We can also tell based on the circuit-ID that router-5
is on DIS on this circuit if we do a show IS-IS database,
notice that we're only seeing a level-1 database
since we configure this router to only be level-1.
And if we do a show IP route IS-IS, notice how few out
we have.
This is because we're looking at the default behavior
where when a level-2 router sends
the routes into a level-1 area or adjacency,
it generates this default route.
This default route is used instead
of all the routes from level-2.
This is part of what IS-IS does automatically
to help reduce the size of the routing table.
So we see that we have the two level-1 entries and that one
default, of course, being generated
by both router-2 and router-4.
Just for final verification, let's go
check on a router outside of Area 10
let's hop over to router-7.
So here, let's do a show IS-IS database.
Remember, this is going to be only a level-2 database
since this is in Area 100, which is our backbone.
If we do a show IS-IS rib, let's look particularly
at router 5's loopback.
We'll say, 10.5.5.5.
And what we're looking for here is the fact
that the R flag is set.
We talked about flags previously in another video,
and we said that the R flag is used if this
is leaked between areas.
And we can see here that that's what this has done.
It's been leaked from level-1 to level-2.
If we look at that route, we see that we actually
have two paths to get to.
It one of them is through router-3.
The other one is through router-1,
which means that if we were to trace to that destination,
we'll source it from our loopback,
we can see that it's actually doing load-sharing
through the environment, which is
exactly what we would expect.
So we see here that we have IS-IS up and running in Area 10
exactly as we designed it.
In this video, we took a look at how
to set up our second area where we did things
just a little bit differently by having some level-1 adjacencies
on our LAN segment.
Then we verified how the databases
are configured to have just level-1
on the level-1-only router, router-5.
But how we had both databases on our level-1/level-2 routers,
that would be routers 2 and 4.
Then we of course wrapped up by doing a traffic test
and verifying that we actually have load-sharing going
on through our network even into the other area where it only
has some level-1 adjacencies.
I hope this has been informative for you,
and I'd like to thank you for viewing.