[AUDIO LOGO]
So now that we've done a little bit
of planning on how we're going to implement IS-IS
in our environment, let's jump in
and start on the command line configuring Area 100.
So as a reminder, we'll jump back
into the topology real quick just so we know what interfaces
and devices we're dealing with.
And then we'll jump into the command line
and get IS-IS up and running in our first area.
So again for this skill, we're going
to be using IS-IS Topology 1, which we've already looked
at in the previous video.
In this video, we're going to be focusing here on Area 100.
That means that we're going to be
configuring router-1, router-3, router-6, and router-7.
Now, on these devices, we will be configuring
all of the interfaces shown on the diagram,
and that will include the gigabit-0000 interface
on router-1 and router-3 even though that's
going into Area 10 because that is still
part of this router that's in Area 100.
Something else we'll be configuring
is we will configure these two interfaces as point-to-point
since they just have two routers on the ethernet segment.
Now, the land between routers 1, 6, and 7, this
is going to stay as a LAN because again, this
is a multi-access network.
Also note that when we configure Area 100 on these devices,
we will be using the readable format so that it actually
looks like Area 100.
So all of that said, let's go ahead and get started.
Let's jump into the command line on router-1.
So the first thing we need to do is, of course,
enable the IS-IS process.
So we'll say router IS-IS, and we'll just
give it a process number we do with OSPF.
We'll just say 1.
The next thing we need to do is configure our net number.
We can see here, it tells us the format
we need to use for the net number.
Now, as we mentioned in some previous skills,
this is usually going to begin with a 49.
Then it's going to be followed by the area number.
Again, this is going to be in Area 100.
And then this is followed by the system-ID.
And since this is router-1, we're
simply going to make it 1.
And then, again, the net number always ends in two 0's.
The next thing we're going to do is set the router type.
So we'll say is-type.
And you can see, again, we have three choices--
level-1, level-1-2, and level-2-only.
Now, we know that IS-IS doesn't really have a backbone
area like OSPF does.
However, we're going to configure this like Area 100
is acting like our backbone.
So what we're going to do is we're
going to configure these as level-2
with level-2 connections between them.
So we're going to say level-2-only.
Next, we're going to start configuring our address family.
So we're going to go in address family IPv4.
Let's set our router ID.
We will set this to the loopback-0 interface.
Let's turn on wide metrics.
So we'll say, metric-style wide.
Let's enable our loopback interface.
And then we'll begin to configure our gigabit
interfaces.
First thing we'll do is we'll set the circuit
type to level-2-only.
Now, this is gigabit-0000 on router-1.
So this is going to be a network type of point-to-point.
And we'll enable our address family.
We'll do the same thing for interface gigabit-0001.
Once again, this is going to be level-2-only.
It's also going to be point-to-point.
And we'll enable our address family.
Now, gigabit-3 is going to be almost the same.
It's still going to be circuit type level-2-only.
And of course, we still need to enable our address family.
But what we're not going to do here
is set it to point-to-point because this
is that multi-access segment.
So this is going to remain the default of LAN
or broadcast network type.
Let's go ahead and commit those changes.
We'll exit configuration mode.
And let's do some verification.
Let's start with a show IS-IS protocol.
So we see here that this is IS-IS router-1.
We see the system-ID is also set to 1.
We see that it's a level-2-only router.
We see that the area is set to 49.100,
which is essentially Area 100, and that those are the areas
that it's routing for.
Those are the things we're concerned
with at the moment as well as if we scroll down
here a little bit.
We see that we are currently running address family IPv4
unicast, again, as a level-2.
And we see that our interfaces, the loopback-0,
and the gigabit 0, 1, and 3 interfaces
are all enabled for IS-IS.
We can also do a show ip protocol.
This is essentially the same information.
It's just showing us that IS-IS is,
in fact, enabled for IP, which we did see on the other output.
This is another way of seeing, basically,
that same information.
We can also do a show IS-IS interface brief.
And we can get some information about our different interfaces.
At the moment we can see that they're only
enabled for level-2.
We don't currently have any adjacencies.
However, they are all up from the perspective of CLNS.
So next, let's jump over and configure router-3.
It's going to be almost the same.
So first, we create IS-IS.
Our net number, of course, is going
to be a little bit different.
It's going to be 49.0100.
But then, we're going to make this system-ID 3.
So this is just the format we're going
to use for the net address.
Again, we'll set it to level-2-only.
Under address family IPv4 unicast,
we'll set the router-ID to loopback-0.
Again, metric-style wide.
And then we'll configure our interfaces.
So interface loopback-0.
We'll simply enable the address family, interface gig0.
Again, it's going to be level-2-only.
This is going to be point-to-point.
And then we enable the address family.
Same thing for gigabit-1 and gigabit-3.
Unlike router-1, this interface is also
going to be point-to-point because this is not
on a multi-access network.
So again, we apply the address family.
And then we'll commit our changes.
So we have our console message that IS-IS has started up.
Let's do our show IS-IS interface brief.
We see this is a very similar output to what we
saw on router-1, except, note that
out the gigabit-0001 interface, we now
have a Layer 2 adjacency.
This should be our connection up to router-1.
Show IS-IS neighbors confirms that this
is a point-to-point connection out gigabit-0001 to router-1.
We also can see, of course, that this is a level-2.
So far, so good.
And honestly, we should actually have a couple of routes
at this point, at least router-1's loopback.
So if we do a show IP route IS-IS,
there's also a few other interfaces
connected to router-1 we should see.
And in fact, we do.
We see router R1's loopback as well as router one's connection
over to routers 6 and 7 as well as its connection to router-2.
So far, this is working exactly as designed.
Let's now jump over and configure router-6.
Now, of course, router-6 is going
to be a little bit different since we've
been doing this on IOS XR, and router-6 is IOS XE.
So let's take a look.
First, of course, we still have to create the process.
We still have to set the net number.
And we'll configure it exactly the same way.
But of course, this is going to be system-ID 6.
We set the router-ID right here.
So we'll again set this to loopback-0.
We'll set the metrics style to wide
and we'll set the is type 2 level 2.
So again you see the very similar configuration we just
don't have to go into the address family
to configure most of these then here's
where the big difference is we then go out to our interfaces.
So now, we go out to interface loopback-0,
and we say IP router IS-IS 1.
This puts the loopback-0 interface
into the routing process.
We'll do the same thing for interface gigabit-1.
And we'll also set this for level-2.
We can see neighborships already coming up,
of course, even though we haven't
configured that part yet.
So this is going to be IS-IS circuit-type level-2-only.
Interface gigabit-2 is going to be very similar.
It's going to be enabled for the process, of course.
It's going to be set to level-2-only,
but it's also going to get IS-IS network point-to-point.
We'll go ahead and exit configuration.
And again, we can just do a show IS-IS neighbor.
We can actually see that at least one neighbor already came
up, our connection to router-1.
Now, from router-6's perspective,
that would be its only neighbor at this point
until we bring up router-7.
So let's go configure router-7 as well.
Again, going to be almost an identical configuration.
Of course, the net number is going to be different.
The rest of this is pretty much going to be the same.
So that takes care of gigabit-2.
We need almost the same configuration on gigabit-3.
And of course, we didn't do interface gigabit-1 yet.
I'm doing this one last just because this one doesn't
get the point-to-point.
So once again, we have to bring it into the process,
and we're going to say that it's level-2-only.
But gigabit-1 is multi-access, so it's
going to go with its defaults.
Let's exit out of configuration.
And let's do a show IS-IS neighbor.
We can see, of course, in the console messages
that many of these neighbors are up, but let's just go ahead
and verify it.
And we see that we are, in fact, up with router-1 and router-6.
That's our multi-access segment.
We can see that they're both out gigabit-1.
And we can actually see based on the circuit-ID.
Since it's R7.01, that actually indicates that router-7 that
we're on right now is the DIS on that segment.
We can also see, of course, our neighborship with router-3
here.
Now, that's a point-to-point connection,
so there's not going to be a DIS on that circuit.
Just to verify that we're getting entries,
let's do a show IS-IS database.
And we can see that we're aware of router-1, router-3,
router-6, and router-7 in this IS-IS area.
If we do a show IP route IS-IS, we
should have quite a few routes at this point.
Notice, they're all level-2, but we do have all of the routes.
In fact, we have routes to router-1, 3, and 6's loopbacks
as well as the transit links between each of those devices.
Another command that can be useful is show IS-IS rib.
This will give us some detailed information
about these different prefixes and such in our database.
We don't have to look at all of them.
But one of the big things to watch for here
are the prefix attributes.
The X actually indicates that this is an external prefix.
The R indicates that it was a re-advertisement or a leaked
route.
We'll be talking about leaking routes between levels
in a future skill.
And we'll see that this R flag gets set on those routes
when they are leaked.
And the N is indicating that this prefix is the node-ID.
In our examples here, notice how that's only
set on the loopbacks because the loopbacks are,
in fact, the router-IDs.
Notice here at the bottom this transit network,
which happens to be the network between routers 1, 6, and 7,
does not have the N flag set because that's not
anybody's router-ID.
Just to do some traffic verification, how about
we try something like a trace.
We'll trace to router-1's loopback.
And we'll just source that from our loopback
and make sure we have reachability.
We see that we do, but these are pretty much directly connected.
Let's see what happens if we try to go, say,
from router-6 to router-3, which are not connected.
So on router-6, let's trace the 10.3.3.3 and source
that from our loopback.
This is equal cost paths.
So what this should do is actually some load-sharing.
And we can see here that that's exactly what it did.
It did load-sharing between router-1 and router-7.
In this video, we got IS-IS up and running,
both on IOS XR and IOS XE, with all the devices being
in the same area.
And we configured our point-to-point connections
where we needed to, as well as configuring
all of the devices and the circuits to be level-2-only.
So we're treating Area 100 here a little bit like a backbone.
Then we, also, of course, verified
that our neighborships came up that were learning routes
from those neighbors.
And they're, in fact, usable because we did some tracing
and verified reachability.
I hope this has been informative for you,
and I'd like to thank you for viewing.