In this video we'll take a look at the configuration steps
to implement and then verify stub routing with EIGRP.
And let's start with a good game plan.
And let's, for this game plan, let's imagine
that R8 is a branch office.
And up here we have the corporate network.
And what we could do is, we could say,
if we lose a route in EIGRP, let's not bother. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
if we lose a route in EIGRP, let's not bother.
Traditionally, we would, by default, R3
would send the query to R8, its neighbor.
R7 would send the query to R8.
R6 would send the query to R8.
And what we can do is we can train the entire network to not
send those types of queries to R8, who is the network up here,
by simply making R8 an EIGRP stub.
Now there are a few flags that we
can add to that, including directly connected networks.
Because R8, if he's directly connected here,
and we want that information advertised-- so here's
what I propose we do.
In the previous video, we had a loopback interface on R1 WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
In the previous video, we had a loopback interface on R1
that we shut down.
And we saw queries go all over the network,
including down to R8.
Once we configure R8 as a stub, when we lose a loopback up
here in the corporate area, in the corporate network,
we should not see the queries for that specific network
being advertised or being sent down
to R8 because the neighbors R6, R3, and R7 will all
know that R8 is a stub.
And they won't bother making the request.
So let's start with verifying our neighborships. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
So let's start with verifying our neighborships.
We'll do a show IP EIGRP--
and, again, you could do the show EIGRP address family IPv4.
This is a little bit quicker, a little less typing.
Neighbors detail, and so this shows us
from R6's perspective its neighbor
of R8, which is right there.
The other neighbor is R3.
We'll do a show IP EIGRP neighbors.
And let's go for detail.
And that shows us about the neighborship with R8
right there.
And also R7 is a neighbor, based on our topology of the show IP WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
And also R7 is a neighbor, based on our topology of the show IP
EIGRP neighbors detail.
All right.
Fantastic.
Just looks like a normal neighbor.
No problem.
And just for grins, on R8, let's do a debug of EIGRP packet
or queries.
And now with that on, here we have some packets
that are being shown here, but no queries at the moment.
And just for grins, here on R1, let's just do a baseline test.
We'll go to interface loopback 0.
We'll bring it down.
That should activate queries throughout the entire network.
Oh, I don't have a console message. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
Oh, I don't have a console message.
I've been playing around with this lab.
Let me bring it up.
We'll do a no shut, yeah.
If it was shut and I shut it again,
it's not going to really start looking for that route.
All right.
So it is up.
And we'll do a shut.
And that should trigger the queries.
Great.
All right.
Let's go back to R8.
And here on R8, I'll do an undebug all.
All right.
And with debugging turned off, here we
have some queries that are coming in.
So here's a query we received on 3/2.
If we scroll up, we should probably WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
If we scroll up, we should probably
have a query coming in on a few other interfaces as well.
And we do.
We're also sending queries, too.
So we got the query.
We're sending queries to our neighbors, hey,
anybody know where this route is?
It's a lot of querying going on.
So what we'll do to solve that is we
will go ahead and configure this router R8 to be a stub router.
And now it's done a couple different ways.
So let's do a show IP protocols and see
what we're dealing with.
So we are currently working with named EIGRP.
So it's done slightly different.
The command's the same, EIGRP stub either way-- WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
The command's the same, EIGRP stub either way--
either in router configuration mode for EIGRP
if we did it traditionally, or we'd
do it under the address family if we're doing named EIGRP.
But the command is the same, EIGRP space stub.
And then there are some options for connected.
And I'll show you those here in just a moment.
So let's do a show run section router.
And that way it will save me a little bit of typing.
And here we go.
So we'll go into configuration mode.
And let me take router EIGRP our EIGRP.
And then, that's enough. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
And then, that's enough.
I'll just paste that in.
And here inside the address family,
we'd use the command EIGRP space,
and then we specify "stub".
So the keyword "stub" here, by itself, means,
I'm the end of the world.
There's nothing else behind me.
But in our case, we do have something behind it.
We have a connected network, 192.168.1
that we want to go in.
So we can add the additional options
about what we want to advertise, even though we're
the end of the world.
So we'll stay connected.
That will get our gig 0/0 interface on R8.
And I'm not doing any static routes.
I don't have any summary routes. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
I don't have any summary routes.
But we could advertise that as well.
We'll press Enter.
And that's going to modify our neighborships.
We have three neighborships.
And now if we go to R6, and I'll show you
where that is in the topology.
If we go into R6 or R3 or R7 and those commands
are all queued up.
And we'd look at the neighbors.
Let's go to six.
So here on R6, if we use the Up arrow key.
Show IP EIGRP neighbors detail.
Look at this-- stub.
So it's a stub.
So that means that R6 will not bother asking R8 WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
So that means that R6 will not bother asking R8
if there is a route that's gone missing.
So he might say, it's gone missing.
But hey, R8 is a stub.
So I'm not going to bother asking him
because he won't know.
So we're saving ourselves a request.
So to verify that, let's go back here to--
and let's also verify that from R7's perspective.
So he sees R8 as a stub and also R3.
Everyone knows it.
Yeah, there we go.
Everyone knows that R8 is a stub.
So if we did debugging here on R8 as a test, WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
So if we did debugging here on R8 as a test,
I don't need to go to configuration
mode for debugging.
So we'll do an Up arrow key a few times.
And we'll do a debug of EIGRP packets query.
And let's go back to R1.
We'll bring up that loopback interface with a no shutdown.
We'll give that a moment to synchronize,
be happy with that.
I was going to say be passive with that.
So the word passive in EIGRP is a good term.
It means, hey, we know where the route is. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
It means, hey, we know where the route is.
The topology table is all settled.
And let's just peek at R8 for a moment.
We'll do a show IP EIGRP topology for 1.1.1.1/32.
And all right.
That's great.
So let's go ahead back to R1.
And on R1 we'll do a shut.
And it'll take a moment.
But we're not going to see queries
for that specific route being sent to R8.
Now, R8 might be asking other devices
because they're not stubs, hey, where's this network?
But as far as receiving those requests, not going to happen-- WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
But as far as receiving those requests, not going to happen--
or at least that's the plan.
So we'll do an un all for undebug all.
And let's go ahead and scroll up a little bit and take a look.
And there we go.
So we're in queuing a query, mean
we're sending a query out 3/2 to our buddy there.
We're sending a query to 4/1.
We're sending a query to 3/1.
But what I do not see here is I don't see anybody
who is sending us a query.
And that is because those three neighbors that we have,
that R8 has, know that R8 is a stub.
And they're not going to bother sending a query. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
And they're not going to bother sending a query.
So that's also going to avoid a stuck in active
scenario because R8 never is going
to be asked about those corporate networks when they're
missing or not there.
R8 is not going to get the queries
for those remote networks.
So check this out.
In the very next video, I'm going
to give you a hands-on lab that you
can do to practice both implementing and verifying
EIGRP stub routing for yourself.
So I'll see you in that video and lab in just a moment.
Meanwhile, I hope this has been informative for you
and I'd like to thank you for viewing. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
and I'd like to thank you for viewing.