It's not fun when we hear a term and we're
supposed to know what it means, we're like,
I don't know what that is.
So in this video, what I'd like to do is chat with you
about some of the vocabulary terms that are associated
with EIGRP so that when you see them, you'll think, oh yeah,
I know what that does.
And so that's the focus of our video today,
to better understand some of the EIGRP vocabulary.
So let's start the party using this topology
with all eight routers-- WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
with all eight routers--
R1, 2, 3, 4, 5, 6, 7, 8-- all of them
running EIGRP with the network 10
included as part of the network statement for EIGRP.
And let's pick on one router.
Let's go ahead and focus just on R3.
And regarding this remote network of 10.2.68,
R3 should know about that route.
It should know about it because it learned it via EIGRP.
And the way routers put routes in the routing table,
they think, OK, here's all the sources for this network.
And it looks for the one with the lowest AD. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
And it looks for the one with the lowest AD.
And then if it has two or three routes with the same AD,
it will go ahead and base it on cost,
put the lowest one in the routing table.
So if we go to R3 and do a show IP route,
we should see the route for 10.2.68,
and it should show the administrative distance
for EIGRP, which is 90.
And it should show the cost.
I'm going to go ahead and put cost metric here
because in EIGRP it uses a very interesting calculation
for the actual metric or cost.
So we'll take a look at that.
But that should show up when we take a look at R3 regarding WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
But that should show up when we take a look at R3 regarding
this route for 10.2.68.
So here on R3--
and this is a hands-on lab, so if you're
logged on to the CBT Nuggets website from a computer,
click on the link for the virtual lab
and you can follow right along with me.
So we'll do a show IP protocols.
I just want to verify that it's actually running.
So here it shows us that EIGRP.
I'll scroll up just a little bit.
EIGRP is running in autonomous system one.
Fantastic.
It also has some information right here regarding
how it's going to calculate its metric.
We'll have a separate video on that. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
We'll have a separate video on that.
It has the router ID and an EIGRP.
The router ID is done the same way that it's done with OSPF.
You can hardcode it, or it can use the highest IP
address on the loopback.
Or if there's no loopback, it's the highest IP address
on some other interface that's up when EIGRP turns on.
Here we have the administrative distance.
The default for internal EIGRP is 90.
If we have external, it means redistributed routes
that come into EIGRP, they would have
a default administrative distance of 170.
And then if we scroll down, here's
our network statement that basically
means that 10 anything is going to match. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
means that 10 anything is going to match.
And anything that starts with 10,
those interfaces are now participating in EIGRP
autonomous system number one.
And they'll be sending hellos every five seconds.
And if they see other EIGRP neighbors
on those same subnets in the same autonomous system,
they'll neighbor up and they'll start keeping track of them.
And if they don't see their hellos within 15 seconds, which
means we missed three hellos at five seconds each,
we'll then go ahead and take action, saying, oh my gosh,
that neighbor is dead.
And then from R3's perspective, it knows about three neighbors.
And that would be based on these last octets--
router 1, router 4, and router 5. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
router 1, router 4, and router 5.
Let's take a look at our topology just to confirm that.
So here's our topology.
Here's router 3.
And sure enough, it has a neighbor of R1, right there,
and R5, right there, and R4, over there.
So 1, 4, and 5 are the three directly connected neighbors.
And we can verify those neighbors
with a show IP EIGRP--
if I spell that right--
EIGRP neighbors.
And sure enough, there's our three neighbors
with the interface IP addresses of those neighbors
that we're neighboring with.
So if we do a show IP route and press Enter, WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
So if we do a show IP route and press Enter,
the D's here represent we have EIGRP learned routes.
And if we look for that one network--
and I happened to use it.
I picked it from the list, that 10 2 68,
because it's going to show up at the bottom.
There's the 10 2 68 network.
There's the administrative distance for EIGRP.
Great, 90.
And then here is the whopping metric--
2,173,184.
And the next hop is 10.0.13.1 And the exit
interface we would use if we needed to forward a packet
in that direction is gig 1/0. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
in that direction is gig 1/0.
So what I thought would be fun to do
right now is let's take that one route for the 10.2.68 network
that we just looked at in the routing table,
and let's go ahead and use some new terms that EIGRP would
use for that exact information that we're looking at,
including the route itself--
it has a special name-- and also, the metric or the cost.
It has a special name.
Let's take a look.
And here are the special terms we're going to use.
This route right here, this winner that
got into the routing table, it won.
It succeeded.
It made it.
Congratulations.
We're going to call that the successor. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
We're going to call that the successor.
And if we want to spell it out, we
could call it the successor route--
meaning, if we had many different sources in EIGRP
that were all advertising that exact network,
this is the one that made it.
It made it to the routing table.
It's called a successor route.
So if we ever see the word successor all by itself,
it's referring to the route that made it to the routing table.
Like, congratulations.
You made it.
That's the successor route.
So that's one term in EIGRP that we're going to see quite a bit WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
So that's one term in EIGRP that we're going to see quite a bit
when working with it.
Because if they talk about a successor,
they're talking about the route that made it,
that made it into the routing table.
Another term that we are going to come across
is a term that describes this metric right here.
So in RIP that metric would be a hop count.
In OSPF that metric is called cost.
And here, this metric in EIGRP, for an EIGRP learned route,
that's referred to-- that number is actually referred to
as the feasible distance.
So one way to think of that, to remember it,
would be talking to the router, hey, WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
would be talking to the router, hey,
do you think you could use this route?
And it says, yeah, I guess that's feasible.
I could use that route.
It's got a metric that's agreeable with me.
Sure, I'll do it.
And the reason that this route, 10.2.68, this exact route
got put in the routing table with this entry,
is because of, first of all, the ADs.
The lower the AD, the better.
And if there's a tie on the AD, it's then the lower metric.
So this metric, also known as the feasible distance
from this router's perspective, is
what's used to determine what is the best route.
Again, lower being better for the metric cost. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
Again, lower being better for the metric cost.
And in this case that metric is literally,
from this router's perspective, called the feasible distance.
It is the metric for the successor route.
So there's two terms that we had to take a moment
and kind of let that sink in.
OK.
Successor route is the route that
made it to the routing table.
And the feasible distance is the actual metric
for that winning route.
That's it.
And to let that sink in, here's what
I'd like to do for routers 1, 2, 3, and 4.
I have this table right here. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
I have this table right here.
So this route, right there, 10.2.68, that
is our successor route.
And regarding that route, that specific route,
router 1 is going to have a successor
route for that network, and R3, and R2, and R4.
And what I took the opportunity of doing
is doing a show IP route.
And you can do it in the lab as well.
I did a show IP route for router 1,
router 2, router 3, and router 4.
And I just put in that feasible distance, that metric
for the successor route.
So let's take a moment right now and just verify
that that data is correct, that that WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
that that data is correct, that that
is the metric for the route on our one
that's in the routing table for the 10.2.68 network.
And I'm just going to look at the last three
digits of 928 just to help be able to identify it
in the routing table.
So we'll go back to our lab.
And we'll go up to R1.
And let's do a show IP route, press Enter.
And again, we're looking for the 10.2.68 network, which
is right here at the bottom.
And that ends in 928.
So 2,172,928.
Let's go verify that in our table. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
Let's go verify that in our table.
And there it is, right there.
Great.
Let's go verify the metric for the 10 2 68 regarding
that winning route on R2.
So we'll make a road trip to R2, and it should be ending in 672.
So we'll go up to R2.
We'll do a show IP route, press Enter.
We'll hit Spacebar, and then here's
that route at the very bottom.
And that metric ends in 672.
Perfect.
That matches our table.
So far, so good.
So that's R2.
Let's go to R3 and verify that that ends in 184.
We were just on R3, but I want to double WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
We were just on R3, but I want to double
check this table as well.
Let's do it.
So here on R3, we'll do a show--
actually, it's right here, still in the output
from the previous show command.
So the last three characters are 184.
Looks good.
And then on R4, the metric for that same network, 10 2 68
should be 2,172,416.
Let's verify that as well.
Again I'm focusing on that last three characters
just as a visual representation that the metric is correct.
So up to R4 we go.
And we'll do a show IP route, and hit Spacebar. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
And we'll do a show IP route, and hit Spacebar.
The very bottom route is 10.2.68.
And sure enough, the last three characters are 416.
Fantastic.
So here's what we've done in this lab.
We've taken a look at four routers--
R1, 2, 3, and 4.
They all have a route for 10 2 68.
And do you recall the name of that route?
What would EIGRP refer to that winning
route in the routing table?
And if you're saying, Keith, I think it was successor,
you'd be absolutely correct.
It's the one that succeeded.
It got there. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
It got there.
He made it.
So they all have a successor route for 10.2.68.
And they all have a cost or a metric associated with that.
And that cost or metric is in this column right here.
And in EIGRP, we'd call that metric that each of the routers
has for the successor route, we'd
call that the feasible distance.
That's the terminology.
So we've added two terms to our vocabulary regarding EIGRP.
A successor or successor route, which means
the winner that made it into the routing table.
And the metric for the successor route,
which is the feasible distance. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
which is the feasible distance.
So in the next video, we're going to take this knowledge
and take it one step further, as we add on a couple
additional terms regarding EIGRP.
So I'll see you in that video in just a moment.
Meanwhile, I hope this has been informative for you.
And I'd like to thank you for viewing.