Is it easier to troubleshoot a network that you're already
a little bit familiar with?
The answer is absolutely yes.
And that's the intent of this video and this lab.
[MUSIC PLAYING]
And here's what I would encourage you to do.
If you are logged on to the CBT Nuggets website,
go ahead and click on the link for the virtual lab,
and then bring up this lab environment.
Just takes about a minute and a half
for it to load and initialize.
And then this network topology is running EIGRP.
And I've got a couple questions that I'd
like you to investigate, because in the next video, WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
like you to investigate, because in the next video,
we're going to troubleshoot this.
So this is the functioning workening--
workening.
This is the functioning working network.
And I'd like you to identify are we using
named mode or classic mode?
What are the autonomous system numbers
that we're using on these devices?
What are the K values that are in use on these systems?
Because one of the things--
V-A-L-U-E-S. Yeah.
One of the things we have to troubleshoot
is that if we have two devices and they have different K
values, they are not going to neighbor up.
In fact, let me take a look at a short list of things
that could go really wrong.
We could have neighbors that are in the wrong autonomous system. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
We could have neighbors that are in the wrong autonomous system.
So for IPv4 or IPv6, if they don't
agree on the autonomous system, they won't become neighbors.
If the authentication is wrong between the two neighbors,
that won't happen.
They won't become neighbors.
If we have passive interfaces, that would prevent it as well.
If we had a completely wrong IP address.
So if we had an IP address like, for IPv4, 10.--
let's put it as 12.0.0 here.
And R2 thought it was 10.21.0.0 for IPv4, WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
And R2 thought it was 10.21.0.0 for IPv4,
they would not form neighborships.
You'd get bombs going off saying, hey,
we're the wrong network.
Not the same [INAUDIBLE] connected network.
For IPv6, it's a little bit more forgiving.
Also, check this out.
With EIGRP, if you have 10.12.0.0 here,
if that was the network--
let me just erase that real quick.
I have the technology.
Let's use it. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
Let's use it.
All right.
And back to the pencil.
So if we had 10.12.0.0 on our gig 0/1 interface and it was
a 24-bit network, and over on R2, it was 10.12.0.0/25,
you know what?
EIGRP for IPv4 wouldn't care.
They would still become neighbors.
Although we'd want to have the correct networks.
So that's kind of like a weird exception.
But it's important to be aware of what works
and what doesn't work.
What else?
Oh, if we had an access control list.
If there's an ACL inbound that's blocking 224.0.0.10, which WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
If there's an ACL inbound that's blocking 224.0.0.10, which
is the multicast address for EIGRP,
that's going to stop R1 from seeing R2's hello.
If it's inbound on that interface,
that would probably cause problems.
Or if we have passive interfaces, where we tell--
let's say, if we told R6, fa 0/0, which is passive,
that network would still be included in EIGRP.
But we would not form neighborships
off that interface.
And if we had interfaces that were down, of course, WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
And if we had interfaces that were down, of course,
that would also cause us grief.
I mentioned authentication.
And oh, and the AS number, I mentioned it as well.
So any one of those things could be wrong in the upcoming labs.
And so what I'd like you to do, as I clear that screen,
I would love it for you to log on to this lab topology
and just do some basic--
just do some show IP routes for IPv6 and IPv4.
Maybe look at how the router config is.
Maybe do a ping from, let's say, R4, all the way over to R7, WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
Maybe do a ping from, let's say, R4, all the way over to R7,
to R7 gig 0/0 for IPv4 and IPv6.
Follow the path.
Make sure you're using the optimized path.
Because right now, EIGRP is choosing the optimal paths
based on what the network is.
With Fast Ethernet, and really slow serial, and gigabit,
it's choosing the best paths.
The networks over on this side, the second octet for IPv4,
is a 1.
And over here on the right hand side
down here, the second octet in the IP address is a 2.
And up here in this part of the network,
the second octet is a 0. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
the second octet is a 0.
And then followed by RR, which is the router number.
So 12, and 34, and 35, and so forth.
And for IPv6, they all start with 2001 DB8 6783, and then
RR, referring to the router numbers.
Again, between R1 and R2, it'd be 12, and 34, and 38
between R3 and R8 and so forth.
OK, so that's your opportunity as a warm-up to get familiar.
This is also a great opportunity to practice your show commands
with EIGRP, including looking at the topology table, WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
with EIGRP, including looking at the topology table,
and looking at the feasible successor information
and successor information in that table,
and anything else you'd want to practice with EIGRP
for both IPv4 and IPv6.
It's here for you.
OK.
So have some fun with the discovery lab of what's there
and how the routing all works, because it's currently working.
And in the next video, I will introduce the problems
for both IPv4 and IPv6, which will then give you
an opportunity to troubleshoot and hone
your skills in troubleshooting to get the network functioning WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
your skills in troubleshooting to get the network functioning
once again.
So I'll see you in that next video in just a moment.
Meanwhile, I hope this has been informative for you,
and I'd like to thank you for viewing.