Implementing Cisco IP Routing (642-902 ROUTE) Tutorials
Route Redistribution / Lab 2 - Manipulating Administrative Distance
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Subtitles of the Movie (Implementing Cisco IP Routing (642-902 ROUTE) / Route Redistribution / Lab 2 - Manipulating Administrative Distance)
So we're coming into the last video in our Lab 2 here for Route Redistribution. We're going to talk about how to actually manipulate the Administrative Distance and we're going to manipulate the Administrative Distance on Router 2. We've got to tell Router 2 that you prefer routes learned externally through OSPF. These OSPF External Routes carry more Weight than this route that you learned via EIGRP which is a neat trick in and of itself because this router already believes EIGRP more than OSPF. If we look at the Route Table here, it sees all the OSPF Routes have an, an Administrative Distance of 110 whereas the EIGRP have an Administrative Distance of 90. So that's why these External Routes aren't put in the Routing Table. Now we see them obviously if we do Show IP OSPF Database, we actually see all of the routes to all of these networks, the 10.10.1 through 6 networks being advertised both ways actually. They're being advertised through the other router as well as being as advertised through the Redistribution Process on this router. You'll see the advertised routers 10.10 or 10.100.3.1 and 4.2 and if we look over here, 10.10.3.1 is here and 3.3.4.2 is here. So it's learning about those routes not only from itself but from the other router. So that, it's learning these routes, but it's not putting them in the Routing Table because the External OSPF Routes have a higher Administrative Distance. So how do we fix that? Well we can go into this router and we can tell it, you assign the Administrative Distance of 85 for example to External OSPF Routes and that should make this router believe that those routes are the better routes, which is exactly what we're after. And if you think that will work? If we think through it, yeah, it should work. I mean, you know, we're, we're basically tricking this router into saying, those routes are more, more believable and so you believe those routes before you believe the ones, that, you know, who you're going to believe, me or your lying eyes? So let's do exactly that. So we'll go into Config T, we'll go into Router OSPF 1, we'll hit the Question Mark and the command we're looking for is Distance. We're going to Define an Administrative Distance. So we'll do Distance hit the Question Mark. We'll hit OSPF, we'll hit External, which we're defining OSPF External Distances and we're going to set the Distance again to be 85. Distance OSPF External 85 for the OSPF Process. And once we do that we'll give OSPF some time to sort itself out and put the right routes in the Routing Table. So now we'll do Show IP Route and there are our External Routes to the 10.10.1 Networks. Now it's still learning about this 10.10.6 Network directly through EIGRP because if you'll recall from our previous Redistribution Lab objectives. We're not Redistributing that 10.10.6 Network into OSPF. Now for the purposes of our lab, we'll just overlook that, because quite honestly there's no way to fix that using Administrative Distance. However if this were in a Production Network, about the only way you could fix that would be to set a Static Route for that network. Pointing at this router over here and since this router over here would learn about the route through EIGRP, then the routes would go from here, over to there. In fact let's do that, just to be consistent. So we'll do Config T, let's check the Next Hop Router, which would be 10.100.3.1 so let's go and set this Static Route. So we'll do Config T, we'll do Route, I'm sorry it's actually IP Route, IP Route, the destination which will be 10.10.6.0, the Prefix Mask 255.255.255.0 and again the next hop is 10.100.3.1 and we hit Enter. So if we go out here now and we do Show IP Route, all of those routes should go through that other router and there it is. All of the routes are now going through 10.100.3.1. So let's verify that this actually fixed our issues. Let's go to Corp 2 and we'll Trace Route to 10.10.4.1 for example. So we'll do Trace 10.10.4.1, you'll see that it goes to 10.10.4.2, 10.10.3.1 and then 10.100.1.1 or I misread those IP addresses but you get the, the point. It goes from here, over to there and then up to Corp 1, just like the lab objective said. So that's it, we've done a pretty full Redistribution Lab here. You've got the basic concepts down to apply to Route Maps and Route Filters and Tag Routes and, and make sure that you don't have big Routing Loops and now you're set to jump of into this wild, wild world of Routing. I would suggest that you would build a larger version of this lab on your home lab or if you've got some Cisco Routers, build it up in a Cisco physical Router Lab and, and just go with nuts with this. You can't learn enough about Route Redistribution, especially since it directly applies to BGP because again BGP pretty much, that's the only way you get routes into BGP. So we will stop here with Redistribution and that concludes our discussion.
Tutorial Information
| 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 |
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