CCNP ENARSI - 1.4 Troubleshoot Redistribution - BGP & OSPF Lab

welcome back to another video from your it explained in this video we're going to go through the redistribution between bgp and ospf and some basic troubleshooting that you're likely to run into when you're either conducting this in a lab in the real world or in your sis cisco's ccnp and nasi exam so what you see on screen at the moment has all been configured as far as the bgp processes on router 1 2 and 5 and the lsbf processors on router 5 3 and 4 their respective ip addresses and associating those networks into the routing protocols on each device what hasn't been done is the actual redistribution configuration on router 5 between bgp and ospf so just to give you a bit of an idea let's go into router 2 i'll just open up console session and let's just have a look what's in the uh routing table so router 2 it's just got the connected routes at the moment so it's only got this network and this network and router 1 should have the same connected but then this should come up as a bgp route the 10 200.250 0 0 30 network sorry let's just check that open up a console session and show ip route yep as you can see there's that one bgp route coming through excellent but they're not going to be able to ping any of the lspf routes and then same thing if i go onto these lspf devices they're not going to be able to ping or see those other networks because redistribution has not been configured so let's dive straight into it and configure it on router 5. all right so first actually the end and now if i do show ip route on this device now you can see this one already knows ospf and bgp because it has both routing processes configured and running let's just show you what is in the config so you get a better idea of what's already been configured and we'll start here so you can see i've just configured router ospf 1 basic network advertisements and then router bgp 250 because that's what this one is autonomous system 250 and then this is a default command that just i didn't type that in that's really there and then i just added one network advertisement and one neighbor statement for the autonomous system 200 neighbor and that's it so if we want bgp and rspf to redistribute mutually it's quite simple if you followed the previous video between eigrp and rspf it's basically the same just some slight changes so firstly let's go and redistribute bgp into rspf so if we're redistributing bgp into rspf what routing process are we going to go into it's ospf so you always go into the process that you're redistributing into so if i'm redistributing bgp into rspf you go into lsbf and just as we've done in the past redistribute bgp autonomous system to 150 that's it that's all we're doing let's have one line there so now if i go over to router 3 or 4 let's have a look what we see i'll console into router 4. and now we can see these osbf external type 2 routes for 10.110.200. so these two bgp routes so that's all that it took now we can immediately see those networks let's go back to router 5 and redistribute the other way so now let's go router and i'm going to redistribute into bgp so bgp autonomous system 250 redistribute ospf process id one done all right now let's go look at router one so console into that one show ip route and would you look at that instantly they've come up so if i want to ping so if i go from router 1 and ping all the way over to this interface here so 172 16 100.4 let's see what happens so router 1 172.16.100.4 was it 100 let me just double check yep success so how easy was that simple didn't have to do any custom configuration or changes it just worked straight away now we know that it works the other way in reverse because the ping traffic has to not only reach the end device but also return so that's it done but there is some special nuances that you're likely going to be tested on and potentially could run into that's probably going to answer your question about what is this box over here doing so let me just delete that box and i'll set up an eigrp router over here let me just connect it i'll just go from here to here now hopefully uh router 0 is already configured with eigrp and it's all good to go i'm just going to make a small change on router 4 to get eigrp set up and then the mutual redistribution between lspf and ergrp and then we'll see what the real issue is so let me just console in and go here interface i think it's zero one let me just double check yes zero one um ip address and this one is actually 10 20 30 and then one i'm pretty sure 24 and then i'm just gonna have to um go into this i made a autonomous system 100 network 10.20 to 30 to zero oops and then up comes the neighbor adjacency so now i should be able to if i exit out of this ping 10.20.30.10 excellent all right so if that was too fast then apologies you can go back and watch the ospf and eigrp redistribution video um but i've just configured the eigrp information here on this device and now i'm just going to go into oops i'm going to go up here first into eigrp uh 100 and we're going to redistribute ospf process id 1 and then remembering what we learned last time we've got to match some things sorry not match metric some things so i'm just going to do 1 million and then 1 2 5 5 1 1500 out of that router rspf and now if you're not following along here you need to probably go back and watch the previous video the lab video on redistributing between ospf and agrp but if you have hopefully this is all making sense so far and then process uh sorry it's on system 100 that's it so now if i go into router 0 hopefully i can see all of the lspf routes end and show ip route excellent so i can see the ospf routes here and i can see the bgp routes would you look at that so the 10.100 and the 10.200 so straight away the router 0 can now see these networks because we still have the mutual redistribution here but let's have a look what happens if router 0 tries to ping we'll try router 1's interface over here 10.100.200.1 ping 10.2 sorry 10.100.200.1 which we do have an entry in our routing table for that network but it's failing and that is because of something specific with the redistribution here on router 5 that we need to fix now if i go to router 1 let's just have a look what happens on router 1 in its routing table so you can have a better understanding of what's going wrong so we're troubleshooting here and router 1 does not know how to get to this network over here which is 10.20.30.0 so it doesn't know how to return back when it receives those ping requests and you might be asking why not what why did it work this way why did ergrp learn about the bgp routes but bgp did not learn about the ergrp routes and this is what we're going to find out right now on router 5. so back into router 5 actually i can just close that and go back to this one over here so let's just have a quick look at the config so show run and begin at spf so in rspf we're redistributing bgp 250 and then it's added in that subnets keyword for us as well so it behaves like in the previous video it'll automatically add that in for you if you don't manually specify it when you're redistributing bgp into spf and then on bgp here we have the redistribute ospf 1. so it's all pretty much as we would expect but it's not redistributing the eigrp routes into bgp and the reason is the default behavior when redistributing lsbf into bgp is to only redistribute ospf internal routes okay so on router 5 if i go show ip route this is an internal ospf route and so it has been advertised into bgp this however is an external type 2 route and so it has not been redistributed into vgp that's why if i go to router 1 we'll see 172 16 100 but not 10 20 30. 172 16 100 but there is no 10 20 30. so to rectify that we go in so hopefully you can guess what we're about to go into we're going to go into bgp 250 because we're fixing up the redistribution into bgp we go back to the same command we used before redistributing ospf 1 but now there is some additional information we need to put in so these are the options now this is where we're going to use that command i accidentally almost used before match and these are the options that you have so what you're going to specify is basically a list of the things that you want redistributed into bgp so i still want internal spf routes redistributed in but i also want so for a question mark you can see i can also now put in external now there's an option after that of what type of external do i want to redistribute in just type one or just type two i can't specify both of them together unfortunately so i'll do type one and now external type 2. so i've just created a list of the things that i want redistributed into bgp thanks to the match command so redistribute ospf 1 match internal external type 1 and external type 2 enter so now if i go to router 1 and do a show ip route voila now we see that external ospf type 2 route redistributed into bgp now it just comes up as a regular bgp route as you can see here with the b same as it does down here but we can actually see that network all the way over in bgp ah sorry in eigrp so if i go to ping 10.20.30.10 success so that's all the way from here from bgp through multiple autonomous systems in ebgp into rspf into ergrp success all the way through so hopefully you've followed along and it wasn't too confusing if it was you may just need to go back and revisit some of the previous videos that we've put up otherwise i thank you for watching and i'll see you in the next one [Music] you

Channel: Your IT Explained

Views: 16

Keywords: Ccnp, enarsi, cisco, exam, topics, troubleshoot, tshoot, aus, aussie

Id: pkPuhcNJKh8

Length: 15min 33sec (933 seconds)

Published: Tue Dec 07 2021