Multiarea OSPF for the CCNA - Part 2 Configure

okay so in part two we begin configuring multi area OSPF in packet tracer I'm going to start with our Internet service provider router that's out here outside of our organization so I'll click on the router go to command-line interface stretch this out get to global configuration mode and start by putting in the hostname the ISP router only has one interface the gigabit 0/0 interface so we'll put in the IP address the network is 209 165 216 / 28 I'll make the ISP router the first address in this subnet so that means 17 will be the first useable host and now I need to do / 28 which is 255 255 255 dot - 40 I'll put in the command no shut to turn on the interface and the only other thing I need to do for this router is put in a default route I'll put in a quad zero default route out of the gigabit 0/0 interface control-c to get back to privileged user mode and I'll save the configuration all right I'm done with the ISP router it's just the single interface that we configured with a default route going back out the gigabit 0/0 interface now it's time to configure the asbr router the asbr or autonomous system boundary router has three interfaces the gigabit 0/0 interface that goes to the isp and then two serial interfaces we'll need to configure all three interfaces and then afterwards configure OSPF we'll start with the gigabit 0/0 interface I'll open up the router type enable compte hostname asbr interface gigabit 0/0 IP address 209 165 dot 200 dot 18 the other the ISP is dot 17 so we're a team 255 255 255 done 240 of course I could have chosen any IP address in the subnet I just chose the next available IP address no shut I can make sure that my connection is up by doing a do ping 209 dot one six five dot 200 dot seventeen and I get a reply okay so now that the gigabit 0/0 interface is up we'll move on to interface serial 0 / 0 / 0 will give it IP address 10 1 1 to 255 255 255 dot 255 interface serial 0 / 0 / 1 I P address 10.22 - with a / 30 subnet mask I'll also need to put in a clock rate I'll choose 128 thousand and no shut so now all three interfaces have been configured the next thing that I'll do since we are the boundary router and we have the way out of the network towards the ISP I'll put in a default route quod zero also going out of the gigabit 0/0 interface so now I've configured all three interfaces a default route and now it's time to configure OSPF so to configure OSPF I'll get a prompt here I'll get back to global config mode my router timed out I'll type in router OSPF I need to pick a process ID I'll choose one so router OSPF process ID 1 I'll give the router a router ID number I'll say router - ID since there are seven routers in our organization in packet tracer I'll just choose the IP address seven seven seven seven once again I could have chosen any 32-bit dotted decimal address for the router ID I just chose seven now I need to put in my connected networks now the connected networks that I want to advertise to the other routers in my system so of course the connection going out to the ISP is not going to participate in OSPF the Internet service provider router is not part of our autonomous system so I'll be putting in the 10.1.1.10 network so I'll put in Network 10.11 zero since it's a slash 30 subnet mask 255 255 255 255 card bits will be the inverse the inverse of that is 0 0 0 3 the area is area zero we're in our backbone area and so that's my first network and for the second network it's the same wildcard bits and the network is 10.2 2.0 so those are both of the networks I'll be advertising to the other OSPF routers also since I have a default route to the ISP to the internet I'll put in the command d EF tab default - information originated this will allow me to propagate my default route to the other OSPF routers in my organization that's all I need to do for the asbr router next I'll configure the area border router 1 ABR 1 so I'll click on ABR 1 get to global configuration mode put in the hostname let's start by configuring interface serial zero slash zero slash zero I'll put in the IP address 10.1.1.1 255 255 255 255 and the no shot command the next interface to configure on area border router one is the gigabit 0/1 interface it's connected to the 192 168 1 network so I'll make this interface 192.168.1.1 so I'll type in int gigabit 0 / 1 to get in the gigabit 0 / 1 interface IP address 192.168.1.1 a / 24 subnet mask and a no shut command now it's time to configure OSPF I'll type router OSPF 1 for the process ID I'll give them the router ID v dot v dot v dot v and i also have to advertise my connected networks my connected networks are network 10.1.1.1 instead of putting in the network number which would be 10.11 and then having to figure out the wild card bits which is the invert of the subnet mask you can also put in the interface address which in this case would be 10.1.1.1 and instead of the wild card bits the inverse of the subnet mask I could put in all zeros this would also work now this interface is in area 0 but for the other network notice that as soon as I begin advertising out of the serial interface we get an adjacency change and a neighbor relationship is established with the asbr router the message loading to full full meaningful adjacency so I also need to add the other network which is coming out of the gigabit 0/1 interface network 192.168.1.0 I'll put in this time the wild-card bits 0 0 0 255 which is the inverse of 255.255.255.0 and this this is the fun part this interface gigabit 0/1 is in area one so instead of putting area 0 I'll put in area 1 and we now have multi area OSPF to really see multi area OSPF working we need to configure router r1 here in order to bring up this network between the two routers so I will quickly configure router r1 will open up router r1 configure the hostname go into the gigabit 0/1 interface and put in the IP address 192.168.1.1 figure interface gigabit 0/0 with IP address 192.168.1.1 and bring that up for the to network and then if we look at the diagram you can see that not only do we have this one network here off the gigabit 0/1 and the two network coming off gigabit 0/0 but i've put in a loopback address this is a loopback 0 interface a loopback interface is a null interface it doesn't really go anywhere but it can be used for testing purposes and can also be very useful so what I'm going to do is I'll activate a loopback 0 interface and give it the IP address 192 168 3.1 for the 3 network so let's do that it's basically a virtual or fake interface so I'll put an interface ello 0 all right you can see it automatically comes up and then I'll put in IP address 3.1 so now we have three interfaces up gigabit 0 / 1 0 / 0 and loopback 0 now the 0/0 interface won't really come up until we configure our - but in the meantime let's configure OSPF so say router OSPF one router ID 1 1 1 1 and then add in the network's network 192.168.1.0 is connected to our gigabit 0/1 interface and this is area 1 we also have the 2 network and the 3 network notice that we have an adjacency change we now have an adjacency with ABR 1 the area border router and so we've configured OSPF so this router this router and this router are now all communicating let's take a look at our routing tables if I go into a SBR type enable and show IP route you can see that the router o for OSPF and IA for inter area the asbr router has learned about the one network it's an interesting to dot one six 8.3 network which is also an OSPF inter area route if we go to router r1 and do the same thing show IP route you can see that router r1 has learned about the 10.11 it's an OSPF inter area route and it's learned about the OSPF external to route external type to route a quad zero router default route out of the network so the asbr router was able to successfully propagate its default route to the other OSPF routers in the next video I'll configure our to and then we'll configure summary addresses so that the area border routers can successfully advertise area one to area zero but in a summary fashion which will help keep the routing tables small

Channel: danscourses

Views: 50,703

Keywords: Multiarea OSPF, Open Shortest Path First (Protocol), Cisco, CCNA, routing, danscourses, Packet Tracer, Computer Network (Industry)

Id: q9IMj8OWKPk

Length: 15min 17sec (917 seconds)

Published: Tue Apr 28 2015