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So we're getting into the verification part of our second OSPF Lab and we've gone through all the trouble of setting all this up, it meets all of the lab objectives that we've set up. We've set up the OSPF routing, we've not changed the IP OSPF network except on the East Router. We've configured the DR, we've advertised the Loopback Interfaces and now we're on step five and we still haven't run across this hidden configuration issue, but we're about to, here in just a couple of minutes. So let's get to it. We'll go to the router in Area 42, the Dallas Router and we'll see what we can Ping over here in Area 51. So the first thing we need to do is determine what the Boston and Newark Loopbacks are. So let's go over to Boston, I'll do Show IP Interface Brief and the Loopback over here is 1.1.5.1 and Newark is 1.1.6.1. 1.1.6.1 so we've got routes propagating all throughout our network. If we go to Dallas we should be able to Ping through that router. So if we do Ping 10, I'm sorry Ping 1.1.5.1, well wait a minute, we, we can't quite Ping that network. Well we've got the routes, well we, do we have the routes in the table? Do Show IP Route, yeah we've, we've got the routes in the table here, it's an Inter Area route, it's being advertised via 192.168.2.1 so 2.1 is this West Router up here, so let's see if we can Ping it. Let's Ping 192.168.2.1, yeah I mean, we can Ping from the Dallas Router to the West Router. So let's go over to the West Router and let's see what the routes look like over here. So do Show IP Route, we have 1.1.6.0, it's been propagated to the West and so let's try to Ping 1.1.6.1 from here. So Ping 1.1.6.1 from the West Router. Well there's your problem, the West Router can't get to that Loopback Network either and since the West Router's the next hop for Dallas, well, that, that explains why Dallas can't get there. Now why can't West get there? Well the answer lies right there on the screen in front of you. It's in the Routing Table, you'll see that it's route to 1.1.5 and 1.1.6 is via 192.168.1.3. Now if we refer back to our diagram here, we'll see that it is via this East Router, which makes sense. The East Router says well I know about these networks down here, you need to come to me, if you want to get to these guys. However the way that the network is set up, the West Router can't actually Ping 192.168.1.3. It can't get there from here and the reason why, if we allow that time out there, the reason why is, if we Show IP Interface Brief first off to make sure we're looking at the right interface, serial 0 slash 0.1. So we'll do Show Run Interface Serial 0 slash 0.1, you'll see that it is a Multi-point network, so this interface believes, well hey, I Multi-point, I should be able to get to anything that's on this Subnet just by sending it out my Serial Interface. However, there's not a map between West and East, out, all the traffic has to go from West up through HQ and back down to the East. That's the way the DLCIs are configured right now. Now we could go into the Frame Relay Switch here and just configure another DLCI that says oh well you see, traffic on 201, it spits it out on 301 and everything, but that's going against the objectives of the lab. Correct the hidden configuration issue without the changing the underlying Frame Relay Configuration. So we can't go in and out of DLCI. What we can do is go in and out of Frame Relay Map, because we control these, these End Routers, you know, we, we don't really control this Frame Relay device, I mean we do for the lab, but you know, in a production environment you wouldn't control the Frame Relay providers network. Not without paying them a lot of money and you know, we don't want to have to pay them an extra money just to get from here to here, we can, we can send it through HQ, that's not a big deal. So what we'll do is, we'll just set up another Frame Relay Map, 192.168.1.1. We'll say Frame Relay Map IP 192.168.1.3 goes out DLCI 201 as well. So we'll go into Config T, go into Interface Serial 0 slash 0.1, we will add Frame Relay Map IP 192.168.1.3 goes out DLCI 201 and now we should be able to Ping 192.168.1.3. Well we can't, well why, why can't we? Well remember we have to be able to get from West to East, East also has to be able to send the traffic back to West and again you'd be surprised at the number of people that say well I added the route there or I added this on this West router, why can't, you know, why can't I get across my WAN and back to me? Well you may have a route to get there, he doesn't have a route to get back, you got to have 2-Way communication. So now let's go over to the East and let's add the same Frame Relay Map but going back the other way. We'll do Show Run Interface serial 0 slash 0.1 to make sure it's the right one and it is. We'll get smart this time, we'll just copy this out so I don't have to type all these commands and we'll do Config T, we'll do Interface serial 0 slash 0.1, we'll just paste this in there and we'll change this to a 2 and now if I go back to West, look I can Ping now. And that my friends is the hidden configuration issue. You had to add that extra Frame Relay Map to send all the traffic up through HQ. So now if we go to Dallas, we do Ping 1.1.5.1, we can Ping all the way across our network. Of course we've got horrendous round trip times and if we do 1.1.6.1 as well, we've now Pinged both of the routers in Area 51 from the Dallas Router. And we've verified that our Frame Relay Configuration actually works, it's flowing exactly as it should and this concludes our verification video.
| Course: | Implementing Cisco IP Routing (642-902 ROUTE) |
| Author: | Greg Dickinson |
| SKU: | 34291 |
| ISBN: | 978-1-61866-028-2 |
| Release Date: | 2011-12-28 |
| Duration: | 10 hrs / 105 lessons |
| Work Files: |
Yes |
| Captions: | No |
| Compatibility: |
Vista/XP/2000, OS X, Linux QuickTime 7, Flash 8 |