In this video, we're going to do traditional configuration of OSPF for IPv4
using this topology.
So in the lab environment, which I have for you at the end of the set of videos
,
I've got three little virtual machines PC7 at this IP address for IPv4.
I've got a little machine down here PC8 at this IP address and I've also got a
little PC here PC1
at this IP address. They're already correctly set up with their default gate
ways.
I also have our server one nugg, which is sitting logically on this network
segment at .100. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
segment at .100.
It also has a correct default gateway and I've also got a little Windows 11
machine that's also
sitting up here on 10-0-1 that you can use as well. So once this is built and
set up,
when you do the lab, feel free to take advantage of testing and working with
any of those devices
connected to this infrastructure. And also notice here, I'm not including as
part of any OSPF area,
this serial link here, nor this one here. So let's demonstrate this
implementation of OSPF and
as promised at the end of this set of videos, I'll put you on a lab where you WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
as promised at the end of this set of videos, I'll put you on a lab where you
can get the hands on
practice yourself. And here we go. So on the desktop in the lab environment, in
fact, if you want to
follow along as I do these, feel free. The link is near the bottom of this set
of videos.
So once again, if you don't want to wait and do the lab at the very end, you're
welcome to join me
and do them step by step as we do them together. So here is an icon for the lab
topology on the desktop.
I'm going to double click on that to open it up. And this represents our top
ology here that we're
going to be building. And then actually access the console for these devices. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
going to be building. And then actually access the console for these devices.
We're going to go
ahead and go to server one. So server one, not only is it in the bottom right
hand side of our
topology, but it's also going to be used for console access to each of our rout
ers. So I'm going to
go ahead and double click on server one, give that a moment to initialize, and
there it goes. And then
I also have a little notepad document that's currently open. So this little
document called OSPF
configs, you can use it as a reference or you can use it to copy paste if you
want to. If you want to
brush up, however, when you do the lab, if you want to brush up on the commands WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
brush up, however, when you do the lab, if you want to brush up on the commands
, I would recommend
doing at least a few routers manually. And then you can copy paste the rest
just to make sure you have
a comfort level with the commands needed to implement it. So the first thing I
'm going to do is I'm
going to make sure that there's no routing protocols whatsoever. In fact, there
isn't. So I can
actually do this. This little icon right here, that little carriage return
symbol, if we click on
that, here we get issue commands, we can type the commands here, and then issue
them to multiple
routers. So if we do a show IP protocols and press center, and then I select
all for all routers WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
all for all routers
and scroll down, I don't want to send that to PC 8 PC 7 or PC 1 because they're
not routers,
and then click on send script, it'll send that command to all eight routers. So
OSPF is not configured.
So let's go back to our notepad document here. And on R1, what I'm going to do
is simply go into
configuration mode, start up OSPF process ID1, and that's specify auto cost
reference bandwidth to a
thousand, and then use this network statement net 0, 0, 0 with a wildcard bits
all on, and assign
any interfaces that match that network statement to area 0. So we'll just right WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
any interfaces that match that network statement to area 0. So we'll just right
click on that, copy,
go to R1, and right click and paste away. And it's done. Now another thing that
's interesting,
and sometimes I'll do it, so I'm going to explain it now in case I do it
accidentally. If I go into
router OSPF1, and I say network 0, 0, 0, 0, space 0, 0, 0, 0, 0, I know those
wildcard bits are all set to 0,
but a long time ago, some of it Cisco said, you know what? If somebody's going
to do that, they probably
mean all interfaces. So even though I said all zeros there for the wildcard WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
mean all interfaces. So even though I said all zeros there for the wildcard
bits, if you do a do show run,
section router, and take a look, it actually flipped them for us. So that's the
little heads up,
in case I ever do a four zeros for the wildcard bits, what it's really going to
do with OSPF is flip them
all over and just put them all as bits on. All right, so that's router one
configured. So now we'll do a
show IP OSPF interface brief. Now I've got four interfaces involved with OSPF.
So on the left has the
interface number, has a process ID, the area those interfaces are in, the IP WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
interface number, has a process ID, the area those interfaces are in, the IP
address associated with
those interfaces, their cost, and their states. So you're on the left side of
the interface, and then
their respective process IDs are all part of OSPF process ID one, the area that
they're all in, area zero,
their IP address and mask that they all have, their cost. So a loopback
interface is going to have a
cost of one, and the other three interfaces are gigabit, and their current
state. So all the three
ether interfaces are acting as a DR, because there's actually no competition
out there. As far as WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
out there. As far as
neighbors, the second character there, the C is for connected neighbors,
neighbors that we see out
there, and the first number there is the fully adjacent. So we have no
neighbors out there, and no
full adjacent season. That's because we haven't configured the rest of the rout
ers yet. So let's go to
router two, and it's a very similar treatment. So if we look at the topology
again, router two,
all of its interfaces are associated with area zero. So we'll go back to our
text document. I'm going
to grab the config here for R2, and copy that, and then make sure I'm on the
right router R2, WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
right router R2,
paste away, and away we go. And then we'll go to R3. Now R3 is going to be a
little bit different. Let's
take a look. So here on R3, we're going to have gig one zero in area zero, fast
-eat-at-four zero in
area zero, but interface fast-eat-at-four slash one is going to be assigned to
area one. So let's take
a look at the config for R3. So for router three, we'll start the OSPF process
one. We'll set the auto
cost reference bandwidth to a thousand, and then I'm going to put the loopback
interface, which is
three dot three dot three dot three in area zero. And then I'm going to specify WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
three dot three dot three dot three in area zero. And then I'm going to specify
the 10 zero, anything,
is going to be an area zero, and 10 one, anything is going to be an area one.
Let's take a look at
our topology once again. So this one is 10 zero, and this is 10 zero. So that
network statement should
put both of them in area zero, and this interface fasting at four slash one is
10 one. So that should
put it in area one. And then for the loopback, I just put that loopback three
three three three into
area zero. Although we also could have put it in area one. Normally though, I
'll put the loopback
in the backbone area if it's an ABR. All right, so let's go grab that config WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
in the backbone area if it's an ABR. All right, so let's go grab that config
copy and make sure
on the right router are three right click. And away we go. So we do a show IP
OSPF interface brief
press center. I've got three interfaces in the weight state. So this one right
here gig one zero is
the interface that goes up to R1, and because R1 had already become the
designated router for that
segment and was established R3, when it saw that said, okay, you're the DR,
there's no BDR present,
I'll go ahead and be the BDR. And then here in just a moment, if we wait long
enough, those three
other interfaces should all act as DRs as well. And that's here in this column WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
other interfaces should all act as DRs as well. And that's here in this column
called state. So let's go
ahead and do a up arrow key show IP OSPF interface brief. And there we go. And
if we bring up the
topology, let me scoot this over to the right a little bit so we can see
everything. So let me line
these up here on R3. F8 four slash zero is the DR for that segment. And that's
because there's
nobody out there yet. I haven't configured R4 yet. And that's an area zero. And
gig one zero is an
area zero. That's this one. And it's the BDR because R1 was already established
DR on its gig two zero
for that segment. And then gig zero zero not shown in our topology, but that's WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
for that segment. And then gig zero zero not shown in our topology, but that's
right here. That's
acting as a designated router. And then off gig zero zero there, there's no
neighbor. So he's all
by himself on that segment. So he's the DR. And then F8 four slash one, which
is right here,
it's acting as a DR for that segment. And that's in area one again, that's four
slash one.
All right. So there's our three configured and we're going to follow that same
logic as we configure
our four and all the way down to our five, our six, our seven, and our eight.
And here in the topology,
I put the odd numbered routers on the left and the even numbered routers on the WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
I put the odd numbered routers on the left and the even numbered routers on the
right. Let's go
back to our notepad document. Again, that notepad document is on server one. So
we'll get into our four.
We'll copy that. And with our four, we're going to have two of its interfaces,
the F8 four
slash one and gig two zero, which are both on the 10 zero address base going to
be part of area zero.
And then the serial three slash one that goes down to our six, that is the
address base of 10.2.
And that's going to become associated with area two based on our network
statements.
So we'll right click and make sure we go to the right router, our four and WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
So we'll right click and make sure we go to the right router, our four and
paste. All right. And
there's our Json C's over to our two and also to our one. We'll continue down
to our five. Our five
has all of its interfaces in area one. That's on the left hand side of our top
ology. So we'll copy that.
Go to our five, put that in, and then we'll go to our six and grow our six
right click copy.
Our six is on the right hand side of our topology. All of its interfaces are in
area two. And then
we'll go to our seven right click copy and on our seven, go and paste that in. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
we'll go to our seven right click copy and on our seven, go and paste that in.
And all of its
interfaces are in area one. And then finally our eight. So we'll grab our eight
s config and copy.
And all of its interfaces are in area two. So I could have just used a wild
card, but I wanted to
not include the serial interfaces. And that's why I'm using three network
statements. Instead of
using a wild card bit saying all interfaces. Also, we could go into individual
interfaces to
enable OSPF that way. In fact, let me go ahead and demonstrate that on one of
the interfaces. Let's just
grab the first two network statements and we'll go to our eight and paste that WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
grab the first two network statements and we'll go to our eight and paste that
in. And then
let's do a do show IP OSPF interface brief. So the interface I don't have down
on our eight is
the gig zero zero. So another way of doing it is going to interface gig zero
slash zero and
saying IP OSPF process ID one and area two press enter. And we'll do a double
type of end. We'll do
the do show IP OSPF interface brief. A matter of config modes. I don't need to
do. So I can just do
it show IP OSPF interface brief. It'll be much better. And then we have OSPF WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
it show IP OSPF interface brief. It'll be much better. And then we have OSPF
enabled on those three
interfaces loop X zero gig zero zero and F a four slash one all part of OSPF
process ID one as shown
right here. And all those interfaces are assigned to area two. And if we've
given it just a minute,
it'll also figure out that there's no other OSPS speakers on gig zero zero or
off of gig zero zero.
So if we hit the up to okay again, press enter. It should now be the DR for
that segment as well.
All right, so let's have some fun with this. Let's go to our three. That's a
good sample. And let WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
good sample. And let
me scooch over the topology so we can see our three while we're configuring it.
All right, so our
three is right here. I also wanted to take a moment and just verify the actual
cost of those interfaces.
In fact, we don't have to go too far to see it. So here's our three right here.
Oh, you know what?
I want to let's go ahead and take a look at a router that has gigabit, fast
ethernet, and the
serial link associated with OSPF. So let me move the topology over just a
little bit. All right,
so here is our four. Let's go ahead and do the tab for our four by clicking
right here. And here
at our four, let's do a show IP OSPF interface brief and confirm the costs. So WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
at our four, let's do a show IP OSPF interface brief and confirm the costs. So
for gigabit interfaces,
it's this cost of one. Let's just call them right here. So for gigabits, it's a
cost of one for
fast ethernet four slash one, it's a cost of 10. And for the serial interface
three slash one,
it's a cost of 15,625. And that's what we assumed earlier when we wrote that
out in the overview.
So let's do some basic commands to verify OSPF show IP OSPF for center. There's
a lot of
information here. So I'm going to hit the space bar a couple times. Let's WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
information here. So I'm going to hit the space bar a couple times. Let's
scroll up and take a look.
So here's the OSPF process ID and the router ID. So the router ID is going to
be, if it's not hard
coded like 4444, it's going to use the highest IP address on a loopback. If you
have no loopbacks,
the highest IP address on another interface at the time OSPF comes up. So each
of the routers has
a loopback interface with the number matching the router. And that's why router
four has a router
ID of 4444. And as we scroll down before we get to the area information here,
it's showing us the
reference bandwidth is 1000 megabits per second. And that's really important. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
reference bandwidth is 1000 megabits per second. And that's really important.
If you have anything
faster than fast ethernet and you want OSPF to make intelligent decisions, you
'd want to set all
your routers with a higher than default reference bandwidth. So we set that to
1000. And here it's
showing us that area zero, the backbone area is connected to. It's showing us
the authentication
associated with that area. And we have area two as well. Because our four also
has an interface
in that area. So it has one interface in that area and that is serial three
slash one. If we go back
up to the backbone area, it says it has four interfaces. So is that true? Let's WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
up to the backbone area, it says it has four interfaces. So is that true? Let's
do a show IP OSPF
interface brief. Let's see if it has four interfaces in the backbone area. And
it sure does. As shown
right here, that would loopback interface, F a four slash one gig two zero, oh
and gig zero zero,
which isn't reflected in our topology. But indeed does have OSPF enabled on it.
So once again,
we do a show IP OSPF press center go down. We have four interfaces in area zero
and we have one
interface in area two. We could also verify who our neighbors are with show IP WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
interface in area two. We could also verify who our neighbors are with show IP
OSPF neighbor
and press center. And here it's showing us we have a neighbor adjacency with
the router idea 3333.
That's R3 and 222. That's R2 and 6666, which is R6 off of the respective
interfaces.
It's also showing us here, which interfaces is a reach belong. It's also
showing us the state. So
this is saying here in the state column that R3 is the DR for the segment. R2
is the DR for that segment.
And then we have a full adjacency with no DR expected with 6666. And that's WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
And then we have a full adjacency with no DR expected with 6666. And that's
because it's a serial
link point to point link. And we talked about stamp and what has to match for
OSPF adjacencies to
occur. So if we want to take a look, for example, at interface, fast, Ethernet,
four slash one,
we do a show IP OSPF interface, FAA four slash one press center. So there's our
command that we
issued. It says that interfaces associated with area zero. It was attached to
via a network statement.
It's associated with OSPF process ID one. Here's the router ID 4444. Here's the WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
It's associated with OSPF process ID one. Here's the router ID 4444. Here's the
network type broadcast,
which is the default for Ethernet. It also implies that we're going to be
looking for and using
a designated router. And if there's two routers on that segment, a backup
designated router,
there's the OSPF cost based on the reference bandwidth that we set on that gig
abit interface.
Here it has a repeat of that cost in case we missed it the first time. It's
also specifying here
our state. So we are the BDR for the segment. And our three is acting as the DR
. It's also indicating
that here with the designated router at 3333. And we are the backup designated WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
that here with the designated router at 3333. And we are the backup designated
router. And here's our
hello and dead intervals. We could also do show IP OSPF interface brief. And
that would also confirm
our current roles on those segments. So right there's indicating we are the BDR
on the interface
FAA4/1 for that segment. The show IP OSPF neighbor would indicate the roles are
in neighbors.
So off of our fast Ethernet 4/1 interface, our three is acting as the DR. And
then we are acting as
the BDR. And then the neighbor count is showing us one and one. So the second WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
the BDR. And then the neighbor count is showing us one and one. So the second
one there is the count.
And the first one there is the fully adjacent. And if we want to see glimpse of
the LSAs that are
involved because our four is an area border router. It should have LSAs for
area zero and also LSAs
for area two. So we do a show IP OSPF database. That's going to give us
information on those LSAs.
So here's the command show IP OSPF database. Here it's starting off with the
router link states. Those
are the LSA type one for area zero. So our four in area zero has knowledge of WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
are the LSA type one for area zero. So our four in area zero has knowledge of
and is receiving
information about the LSA type ones for all four routers that are in area zero.
Then as we go to
the network link states, that's the LSA type two is generated by the designated
routers in area zero.
So for the 12 network and the 13 network, our one based on the advertising
router is the designated
router. For the 24 subnet, it's router two. And for the 34 network, that is our
three acting as
the designated router. And one of the reasons is in that order is because I
configured those routers WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
configured those routers
in that order. If we configured everything at the exact same time, they would
duke it out based
on priority and then the highest router ID regarding who would be the DR for a
given segment.
But because I did them systematically like one and two then three then four
with some time in
between, that's why our one went out as far as the DR functionality over our
two for the 10,
012 network, even though our two has a higher router ID. And then we go down a
little bit further.
Here are the LSA type threes, which are these summary LSAs. And these are the
networks that are
being advertised by the AVR. So the 555 loopbacked rests 6666, 7777, the 8888. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
being advertised by the AVR. So the 555 loopbacked rests 6666, 7777, the 8888.
So here are the advertising
routers that are propagating those LSAs. So over on the left, our three is
doing the advertisements.
And here on our four is doing the advertisements. And then as we continue to go
down a little further,
it's going to repeat that process. But this time for area two. So here in area
two, we have our LSA type
ones from each of the routers in area two, which is our four, our six, and our
eight. Then we have one WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
eight. Then we have one
designated router in area two. And that would be for the ethernet segment
between our six and our eight.
And based on this advertising router, our six is the DR for that segment.
Because it is the
advertising router. So if we popped over to our six for a moment. And here if
we did a show IPOSPF
interface brief, breastenter, sure enough off of its FA4/0 for that 10.2.68
network, it is acting as the DR.
And it also implies that our eight on its FA4/1 is acting as the BDR. We can WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
And it also implies that our eight on its FA4/1 is acting as the BDR. We can
verify that with the
show IPOSPF neighbor. And then verify right there that our eight is acting as
the BDR for that segment.
So going back to our four, again, here's all the information for area two. So
again, the LSA type ones
are here for area two. The LSA type twos for area two are here. And we're going
to have one. Also,
what's interesting to note though is over here on our eight in area two, it has
gig zero zero. And
it is the DR for that. So why don't we have our eight also as a DR that's
advertising these
network link states for its gig zero zero address. And the answer is if there's WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
network link states for its gig zero zero address. And the answer is if there's
up two or more
OSPF speakers, meaning router running OSPF on a common segment, the device that
's the DR doesn't
need to advertise a network link state because it's the only DR on that segment
. It's only when you have
two or more OSPF speakers where the DR is going to generate that network link
state, that LSA type
two. And that's why we only see one here for area two. And then we have the
summary net link states WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
summary net link states
for area two. And those are being generated by R4. And that's why here for area
two, the only
advertising router is the ABR R4 that's connected to area two. So here are all
the networks that are
being advertised. And if we change the config and we made area two a totally
stubby area, even these
summary routes would be suppressed and not advertised in area two. Instead, we
just advertise a default
route from R4 into area two. And that would save all the routers in area two
from having to know about WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
from having to know about
these detailed routes. So in our small topology, it's not a huge deal, but in a
large network with
hundreds of routers by quarantining off and making separate areas and making
them stub areas,
we can save processing power and resource utilization on those routers in those
stub areas.
So in fact, while we're right here, let's also go down to R8 at the bottom
right of our topology.
And let's do a show IP OSPF database. So R8, because it's only an area two, is
only going to have WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
only going to have
information on area two. So there are the three LSA type ones coming from the
three routers in area two.
Here's the LSA type two coming from R6. And then we have the LSA type threes
that are being advertised
by the area border router. So as a quick example of how changing area two into
a totally stubby area
could help remove all of these summary routes and just get a default route
being advertised by the
ABR. What we'll do is we'll go ahead and on R4, we'll specify that area one is
a totally stubby
area until it not to forward summary routes into that area. So to make that WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
area until it not to forward summary routes into that area. So to make that
happen, we need to make
sure that on this segment and this segment. And also this one, we'll specify
that that area is a
stubby area. Because if they don't agree on the type of area, that will prevent
OSPF from neighboring
up. So to do that, let's go to R4. And on R4, we'll go to router configuration
mode for OSPF
process ID1. And we'll say area two, space, question mark, stub, space question WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
process ID1. And we'll say area two, space, question mark, stub, space question
mark, and no summary.
And I got to spell that out. All right. So what that effectively that does is
tells R4 that area two
is a stub area and not to send summary routes into that area. Now the reason we
just lost our
adjacency was because we have to agree with our neighbor what type of area it
is. It's no longer
a normal area. It's now a stub area. So let's go to R6. And here in R6, we'll
go to configuration
mode for router, OSPF1. And we'll say area two, stub. Now we don't have to say
no summary here because WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
no summary here because
R6 is not an area border router. So it wouldn't be forwarding summaries anyway.
If you add it here,
it won't hurt, but it's not needed. So I'll go ahead and press enter. And you
'll notice we lost our
adjacency with our eight, but we did regain our adjacency with R4 because we
now agree. So now here
on R6, we can do a show IP OSPF. Right here is saying the number of areas in
this router is one,
zero normal, one stub, and zero, not so stubby areas. And right here under area
two, it's indicating
it's a stub area. And then we also need to go to R8 and make sure it knows as WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
it's a stub area. And then we also need to go to R8 and make sure it knows as
well. So on R8,
go to configuration mode, router, OSPF1, and area two, stub. And that should
restore our adjacency
with R6. And there it is. Fantastic. Previously on R8, it had all of these
summary net link states
effectively LSA type threes with all the routes effectively advertised from R4
regarding those
networks. But now that we made it a stub area, and we also told R4 not to send WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
networks. But now that we made it a stub area, and we also told R4 not to send
the summaries,
check it out. Now if we hit the app, or I'll key a few times, and do that same
exact command show
IP OSPF database in press center. Look at this. We still have the LSA type ones
for our four,
our six, and our eight. We still have the DR thus advertising the LSA type two,
but check this out.
For the summary net link states, we only have one. And that's advertising the
default route. So if
we looked at the routing table, it is show IP route press center, you'll notice
. In fact, let's do it
again with a OSPF. We'll filter it down. So we have a default route that's been WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
again with a OSPF. We'll filter it down. So we have a default route that's been
advertised.
Then we have an OSPF learned route. That's R6's loopback. That's an area two.
We have 10246,
which is the network between R6 and R4. What the heck is 1026? Why do we have
1026? I'm curious.
Who's got 1026? Let's go take a look at R6. That's not an R2. It's show IP
interface brief.
I see. So R6 has a 1026 interface. And we do show IP OSPF interface brief. Sure WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
I see. So R6 has a 1026 interface. And we do show IP OSPF interface brief. Sure
enough,
it's enabled for OSPF. And that's why we know about it. So let's go back down
to R8.
I was just curious. Where does that come from? So by turning this area, area
two into a stub area,
and also telling our four to go ahead and not send LSA type threes into that
area,
we're reducing the size of the routing tables on routers in area two, including
R6 and R8. And
just as a quick test, if we want to verify full connectivity, we could go ahead
and try to ping, WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
and try to ping,
for example, it's ping from R8 all the way to this PC7 at 10.1.7.10. So back at
R8, let's go ahead and
do a ping to 10.1.7.10. And that's working. Let's also do a trace just to
verify the path 10.1.7.10.
And then based on the trace, the next top was R6, and then R4, and then R2, and
then R1,
and then R3, and then R5, and then R7, to finally hit the destination, which
was at .10.
So now that we have the opportunity to see the legacy implementation of IPv4 WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
So now that we have the opportunity to see the legacy implementation of IPv4
with OSPF,
in the next video, I like to walk you through the legacy implementation of OSPF
, but this time for
IPv6. So a lot of the same concepts are going to hold true, except the IP
addresses are a lot longer.
So I'll see you in the next video when you're ready.