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One of the benefits of having multiple areas in OSPF is that we can do things

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like summarization

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or we can create an area and make it a stub area or a totally stub area. And in

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this video,

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I'd like to walk you through doing that for the address-fileme IPv4 in the

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world of OSPF version 3.

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And to start off, I also like to show you how we can do redistribution of

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routes into OSPF version 3

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for address-fileme IPv4. So, we'll do that here on R1. We'll take some static

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routes and redistrue

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them into OSPF so they're now external routes. And that would make R1 the
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them into OSPF so they're now external routes. And that would make R1 the

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autonomous system

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boundary router, the device doing the redistribution. And the routes I have

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begin with 10.0.11 and

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there's four or five of them. We'll redistrue the static routes into OSPF for

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the address-fileme IPv4.

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And those will be showing up as LSA type 5s. When R4 sees those, it's going to

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four of those LSA type 5s

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down into area 2. That which point, router 6 and router 8, we'll see those as

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external OSPF routes.

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And the same thing would happen here on R3. It would see those LSA type 5s for

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the individual routes

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and it would advertise those or forward those I should say down to area 1 as L
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and it would advertise those or forward those I should say down to area 1 as L

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SA type 5s.

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It would also include the LSA type 4 that describes how to reach the ASBR that

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did the redistribution

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in the first place. So, why do I bring that up? Well, if we're going to create

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a stub area,

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when we create a stub area, that prohibits if we do it here on R4. A stub area

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will no longer

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forward those LSA type 5s and as a result, it also won't bother saying an LSA

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type 4 into the

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stub area. However, it will still send the LSA type 3s for this network and

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that network and that

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network and that network etc etc etc but it won't send the LSA type 5s. Unless,
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network and that network etc etc etc but it won't send the LSA type 5s. Unless,

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with a totally

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stub area, we tell the area of router router to not send any summaries. So it

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won't send the LSA type 3s

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down into area 2. And that's going to reduce the number routes that these rout

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ers in area 2 have to

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process and look at. And whether it's a stub or a 20 stub area, R4 is going to

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send 1 LSA type 3 and

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that's a default route. So that the routers in that area will have a default

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route that they can

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use to forward to get to for example in a totally stub area to get to these
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use to forward to get to for example in a totally stub area to get to these

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other networks that it

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doesn't know about for sure. It will send me the default route which will bring

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them up to R4

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and then R4 can continue the routing. So this video will do a static redist

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ribution as part of

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OSPFE3 for IPv4 and we'll set up a stub and a totally stub area and we'll use

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that over here in

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R4 for area 2 and then we can compare and contrast the differences. So with

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that in mind, let's head

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over to our router 1 device that's going to act as our autonomous system

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battery router and redistribute

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the static routes that it currently has into OSPF. So let's begin. We're here
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the static routes that it currently has into OSPF. So let's begin. We're here

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on server 1. Let's go

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up to R1 and this is just to a quick confirmation with the show IP route static

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and sure enough it has

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five static routes. So we'll redistribute those into OSPF V3 under the address

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family for IPv4.

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Let's do a show run, pipe, section router and we're going to configuration mode

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. We'll go into

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router OSPF V3 process ID1. We'll further go into address family IPv4 unicast.

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Then here we'll do a

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redistribute space and let's go ahead and pull in the static routes. We'll type
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redistribute space and let's go ahead and pull in the static routes. We'll type

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in static and that'll do it.

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So those five static routes have now been injected and redistributed into OSPF.

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So let's do a show

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OSPF V3 IPv4 database. If you didn't put an IPv4 it'll show you if you have it

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set up for IPv6

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and IPv4 it'll show you both databases. So press enter. So here are LSA type

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ones for area 0.

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Here is our LSA type 2's for area 0. If we go down further here are the LSA

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type 3's for area 0.

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And if we go down below the LSA types 8 and 9. And here we have our type 5, the
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And if we go down below the LSA types 8 and 9. And here we have our type 5, the

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external links and

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there are the five networks right here. Fantastic. So if we go down to R8 and

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we do a show OSPF V3

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database for a center it should also have those five routes and it does as LSA

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type pipes. And as

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result if we do the show IP route let's go ahead and use OSPF. Let's tack on OS

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PF V3. There are those

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five external routes right there in the routing table. So the point of adding

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those external routes is

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that once we make area 2 a stub area our 4 is going to advertise a default
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that once we make area 2 a stub area our 4 is going to advertise a default

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route. It's going to send

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the summary still for all the normal LSA type 3's but it's not going to send

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the LSA type 5's into area 2

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if it's a stub area. So let's go ahead and make our 4, our 6 and our 8 all

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believe the area 2

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is a stub area. So since we're on our 8 let's do a show run, pipe section

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router. Now what we do

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is go into configuration mode and we go into router OSPF V3 process ID1 and
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is go into configuration mode and we go into router OSPF V3 process ID1 and

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here we could just say

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area 2 stub and that would apply to both address families. Or if we want to be

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very specific for

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example you don't have the same type of areas for IPv6 and IPv4 we then go into

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the specific address

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family for IPv4 unicast. So we'll go into that address family and then we can

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go ahead and say area

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to and a question mark and specify that it is a stub. Boom. Now we're going to

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lose the

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naborship with our 6 and that's because our 6 doesn't agree that this is a stub

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area. And just to

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demonstrate the slight difference if we go to our 6 and we go to configuration
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demonstrate the slight difference if we go to our 6 and we go to configuration

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mode for router

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and we go to configuration mode for router OSPF V3 process ID1. Let's do a show

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run, pipe section

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router. Notice here we're not in address family configuration if we said area 2

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stub right here

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that would also work. It's just implying that we want area 2 to be a stub area

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for both possible

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address families. So we just got our adjacency back with our 6 and then we'll

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go to our 4. So we'll

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do a config t router OSPF V3 process ID1 and again we can go into address

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family for IPv4 for just that
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family for IPv4 for just that

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address family or we can do it right here at the router config level to make it

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apply to both.

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So let's go to address family for IPv4 unicast and then here let's go ahead and

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specify the area

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to is a stub. So that way we should get our naborship back with our 6 and there

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it is fantastic. So in

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our topology we've now just configured area 2 as a stub. So if we go down to

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for example r8

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if we take a look at the routing table previously we had all these external

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routes, easily lc type 5s

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that came into the area being forwarded by the area border router but now that
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that came into the area being forwarded by the area border router but now that

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we're a stub area

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those external type 2s should all be gone and we should also have a default

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route. So let's check

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that out with a show IP route OSPF V3 and there is our default route provided

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by the area border

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router r4 and we've hit the space bar you'll notice we don't have any of the lc

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type 5 lcs that

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made it in and as a result we don't have those external routes here anymore but

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we still have

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reachability because we simply use our default route and we want to take it one

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step further we

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could tell router 4 that we want to not advertise a summary at all and that way
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could tell router 4 that we want to not advertise a summary at all and that way

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all those lc type 3s

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for all these intr area routes they'd all go away with the exception of the one

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default route.

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So let's make that change next on our four we're still in address family

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configuration mode

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I'm hit the up arrow key area to stub and some say no summary and boom that

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area border router

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is no longer sending the lc type 3s for all those individual routes and verify

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that we can go back

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to r8 and here it is. If we hit that arrow key and look at the routing again we

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have our

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intr area default route and we have our intr area route for the 10246 network
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intr area default route and we have our intr area route for the 10246 network

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but all those other

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intr area routes they're all gone but we can still ping some addresses there so

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we could

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of ping for example our trace to 10.1.7. and let's look at our topology let's

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go ahead and ping 10.1.7.10

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right there our trace rather to 101710 press enter we still have full

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connectivity across the entire

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network and if we look back at routers in area 1 for example on our 7 let's go
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network and if we look back at routers in area 1 for example on our 7 let's go

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to our 7 and we

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just show up route for osbf v3 learned routes we have all the intr area routes

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and we have the external

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routes and that's because area 1 where our 7 is is simply a normal area and to

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verify that we need

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to show osbf v3 press enter and here showing us that we have one normal area

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and that is area 1 here

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on router 7 where if we went over to router 6 for example on the right hand

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side of our topology

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and r6 is participating in a stub area here if we did that same command of show
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and r6 is participating in a stub area here if we did that same command of show

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osbf v3 and press

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enter here showing that we have one stub area here it's also confirming that

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area 2 indeed is a stub

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area and osbf v3 for the address family ipv4 can also do summary addresses as

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well we've done that

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in previous skills with different implementations of osbf in the next video

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though I'd like to walk and

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do how to do that summarization from one area's routes to another on an abr

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using osbf v3.