One of the benefits of having multiple areas in OSPF is that we can do things
like summarization
or we can create an area and make it a stub area or a totally stub area. And in
this video,
I'd like to walk you through doing that for the address-fileme IPv4 in the
world of OSPF version 3.
And to start off, I also like to show you how we can do redistribution of
routes into OSPF version 3
for address-fileme IPv4. So, we'll do that here on R1. We'll take some static
routes and redistrue
them into OSPF so they're now external routes. And that would make R1 the WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
them into OSPF so they're now external routes. And that would make R1 the
autonomous system
boundary router, the device doing the redistribution. And the routes I have
begin with 10.0.11 and
there's four or five of them. We'll redistrue the static routes into OSPF for
the address-fileme IPv4.
And those will be showing up as LSA type 5s. When R4 sees those, it's going to
four of those LSA type 5s
down into area 2. That which point, router 6 and router 8, we'll see those as
external OSPF routes.
And the same thing would happen here on R3. It would see those LSA type 5s for
the individual routes
and it would advertise those or forward those I should say down to area 1 as L WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
and it would advertise those or forward those I should say down to area 1 as L
SA type 5s.
It would also include the LSA type 4 that describes how to reach the ASBR that
did the redistribution
in the first place. So, why do I bring that up? Well, if we're going to create
a stub area,
when we create a stub area, that prohibits if we do it here on R4. A stub area
will no longer
forward those LSA type 5s and as a result, it also won't bother saying an LSA
type 4 into the
stub area. However, it will still send the LSA type 3s for this network and
that network and that
network and that network etc etc etc but it won't send the LSA type 5s. Unless, WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
network and that network etc etc etc but it won't send the LSA type 5s. Unless,
with a totally
stub area, we tell the area of router router to not send any summaries. So it
won't send the LSA type 3s
down into area 2. And that's going to reduce the number routes that these rout
ers in area 2 have to
process and look at. And whether it's a stub or a 20 stub area, R4 is going to
send 1 LSA type 3 and
that's a default route. So that the routers in that area will have a default
route that they can
use to forward to get to for example in a totally stub area to get to these WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
use to forward to get to for example in a totally stub area to get to these
other networks that it
doesn't know about for sure. It will send me the default route which will bring
them up to R4
and then R4 can continue the routing. So this video will do a static redist
ribution as part of
OSPFE3 for IPv4 and we'll set up a stub and a totally stub area and we'll use
that over here in
R4 for area 2 and then we can compare and contrast the differences. So with
that in mind, let's head
over to our router 1 device that's going to act as our autonomous system
battery router and redistribute
the static routes that it currently has into OSPF. So let's begin. We're here WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
the static routes that it currently has into OSPF. So let's begin. We're here
on server 1. Let's go
up to R1 and this is just to a quick confirmation with the show IP route static
and sure enough it has
five static routes. So we'll redistribute those into OSPF V3 under the address
family for IPv4.
Let's do a show run, pipe, section router and we're going to configuration mode
. We'll go into
router OSPF V3 process ID1. We'll further go into address family IPv4 unicast.
Then here we'll do a
redistribute space and let's go ahead and pull in the static routes. We'll type WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
redistribute space and let's go ahead and pull in the static routes. We'll type
in static and that'll do it.
So those five static routes have now been injected and redistributed into OSPF.
So let's do a show
OSPF V3 IPv4 database. If you didn't put an IPv4 it'll show you if you have it
set up for IPv6
and IPv4 it'll show you both databases. So press enter. So here are LSA type
ones for area 0.
Here is our LSA type 2's for area 0. If we go down further here are the LSA
type 3's for area 0.
And if we go down below the LSA types 8 and 9. And here we have our type 5, the WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
And if we go down below the LSA types 8 and 9. And here we have our type 5, the
external links and
there are the five networks right here. Fantastic. So if we go down to R8 and
we do a show OSPF V3
database for a center it should also have those five routes and it does as LSA
type pipes. And as
result if we do the show IP route let's go ahead and use OSPF. Let's tack on OS
PF V3. There are those
five external routes right there in the routing table. So the point of adding
those external routes is
that once we make area 2 a stub area our 4 is going to advertise a default WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
that once we make area 2 a stub area our 4 is going to advertise a default
route. It's going to send
the summary still for all the normal LSA type 3's but it's not going to send
the LSA type 5's into area 2
if it's a stub area. So let's go ahead and make our 4, our 6 and our 8 all
believe the area 2
is a stub area. So since we're on our 8 let's do a show run, pipe section
router. Now what we do
is go into configuration mode and we go into router OSPF V3 process ID1 and WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
is go into configuration mode and we go into router OSPF V3 process ID1 and
here we could just say
area 2 stub and that would apply to both address families. Or if we want to be
very specific for
example you don't have the same type of areas for IPv6 and IPv4 we then go into
the specific address
family for IPv4 unicast. So we'll go into that address family and then we can
go ahead and say area
to and a question mark and specify that it is a stub. Boom. Now we're going to
lose the
naborship with our 6 and that's because our 6 doesn't agree that this is a stub
area. And just to
demonstrate the slight difference if we go to our 6 and we go to configuration WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
demonstrate the slight difference if we go to our 6 and we go to configuration
mode for router
and we go to configuration mode for router OSPF V3 process ID1. Let's do a show
run, pipe section
router. Notice here we're not in address family configuration if we said area 2
stub right here
that would also work. It's just implying that we want area 2 to be a stub area
for both possible
address families. So we just got our adjacency back with our 6 and then we'll
go to our 4. So we'll
do a config t router OSPF V3 process ID1 and again we can go into address
family for IPv4 for just that WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
family for IPv4 for just that
address family or we can do it right here at the router config level to make it
apply to both.
So let's go to address family for IPv4 unicast and then here let's go ahead and
specify the area
to is a stub. So that way we should get our naborship back with our 6 and there
it is fantastic. So in
our topology we've now just configured area 2 as a stub. So if we go down to
for example r8
if we take a look at the routing table previously we had all these external
routes, easily lc type 5s
that came into the area being forwarded by the area border router but now that WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
that came into the area being forwarded by the area border router but now that
we're a stub area
those external type 2s should all be gone and we should also have a default
route. So let's check
that out with a show IP route OSPF V3 and there is our default route provided
by the area border
router r4 and we've hit the space bar you'll notice we don't have any of the lc
type 5 lcs that
made it in and as a result we don't have those external routes here anymore but
we still have
reachability because we simply use our default route and we want to take it one
step further we
could tell router 4 that we want to not advertise a summary at all and that way WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
could tell router 4 that we want to not advertise a summary at all and that way
all those lc type 3s
for all these intr area routes they'd all go away with the exception of the one
default route.
So let's make that change next on our four we're still in address family
configuration mode
I'm hit the up arrow key area to stub and some say no summary and boom that
area border router
is no longer sending the lc type 3s for all those individual routes and verify
that we can go back
to r8 and here it is. If we hit that arrow key and look at the routing again we
have our
intr area default route and we have our intr area route for the 10246 network WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
intr area default route and we have our intr area route for the 10246 network
but all those other
intr area routes they're all gone but we can still ping some addresses there so
we could
of ping for example our trace to 10.1.7. and let's look at our topology let's
go ahead and ping 10.1.7.10
right there our trace rather to 101710 press enter we still have full
connectivity across the entire
network and if we look back at routers in area 1 for example on our 7 let's go WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
network and if we look back at routers in area 1 for example on our 7 let's go
to our 7 and we
just show up route for osbf v3 learned routes we have all the intr area routes
and we have the external
routes and that's because area 1 where our 7 is is simply a normal area and to
verify that we need
to show osbf v3 press enter and here showing us that we have one normal area
and that is area 1 here
on router 7 where if we went over to router 6 for example on the right hand
side of our topology
and r6 is participating in a stub area here if we did that same command of show WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
and r6 is participating in a stub area here if we did that same command of show
osbf v3 and press
enter here showing that we have one stub area here it's also confirming that
area 2 indeed is a stub
area and osbf v3 for the address family ipv4 can also do summary addresses as
well we've done that
in previous skills with different implementations of osbf in the next video
though I'd like to walk and
do how to do that summarization from one area's routes to another on an abr
using osbf v3.