WEBVTT 1 00:00.000 --> 00:04.160 So now that we have our BGP adjacency, our neighborship set up with external B 2 00:04.160 --> 00:04.720 GP, 3 00:04.720 --> 00:09.090 it's now time to go ahead and start advertising some routes. So let's start off 4 00:09.090 --> 00:10.160 with tier zero 5 00:10.160 --> 00:14.440 and specify that this gateway, their tier zero gateway should advertise. Let's 6 00:14.440 --> 00:14.800 go ahead and 7 00:14.800 --> 00:19.030 advertise the routes here for the 1010 zero network and also the routes over on 8 00:19.030 --> 00:19.760 this segment, 9 00:19.760 --> 00:23.120 which is the 1020. Now currently we're advertising those via OSPF. And what I 10 00:23.120 --> 00:24.160 like to do is now change 11 00:24.160 --> 00:28.240 that and modify it so we're advertising those same networks, but this time 12 00:28.240 --> 00:29.200 through BGP. And 13 00:29.200 --> 00:32.710 because we have our BGP, the partnership here between this external BGP speaker WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 13 00:29.200 --> 00:32.710 because we have our BGP, the partnership here between this external BGP speaker 14 00:32.710 --> 00:32.720 , 15 00:32.720 --> 00:37.030 that's a fancy way of saying a BGP router and our tier zero gateway. If we 16 00:37.030 --> 00:37.840 start advertising 17 00:37.840 --> 00:42.690 these two subnets via BGP, those routes should show up right here on our BGP 18 00:42.690 --> 00:43.920 router. So that's 19 00:43.920 --> 00:47.730 what we get to do right now. Now as part of that too, on this Cisco router, 20 00:47.730 --> 00:49.600 this currently running BGP, 21 00:49.600 --> 00:52.330 let me go ahead and hit the upper key just to confirm we're not learning any 22 00:52.330 --> 00:53.120 routes yet from 23 00:53.120 --> 00:57.450 our peers. And that's the dot 61 edge one and dot 62 edge to, and I'm going to 24 00:57.450 --> 00:58.400 use a command called 25 00:58.400 --> 01:02.310 debug and I'm going to do a debug IP routing. Now the benefit of doing this WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 25 00:58.400 --> 01:02.310 debug and I'm going to do a debug IP routing. Now the benefit of doing this 26 01:02.310 --> 01:03.360 debug IP routing is 27 01:03.360 --> 01:09.140 that anytime on this Cisco multi layer switch anytime the routing tables change 28 01:09.140 --> 01:10.720 for IP version four, 29 01:10.720 --> 01:13.840 we're going to have messages that indicate that that's happening. And that's 30 01:13.840 --> 01:14.720 going to be near real 31 01:14.720 --> 01:18.090 time. So I'm going to leave that debugging on so that once we start advertising 32 01:18.090 --> 01:18.480 routes, 33 01:18.480 --> 01:21.750 it'll be very obvious that those routes are showing up here on this multi layer 34 01:21.750 --> 01:22.720 switch. So 35 01:22.720 --> 01:27.840 if we do this as show IP route and press enter currently, currently I don't 36 01:27.840 --> 01:28.320 have a whole bunch 37 01:28.320 --> 01:32.430 of routes on this device. I've got a default route. It's a static route. And I WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 37 01:28.320 --> 01:32.430 of routes on this device. I've got a default route. It's a static route. And I 38 01:32.430 --> 01:33.280 've got a directly 39 01:33.280 --> 01:38.200 connected network of 192, 160, one zero with the IP address of 121. But I don't 40 01:38.200 --> 01:39.200 have on this Cisco 41 01:39.200 --> 01:44.170 router any routes for 10 10 or 10 20 yet also take a moment and go back to our 42 01:44.170 --> 01:45.200 VRF for a services 43 01:45.200 --> 01:49.400 router. And we do a get BGP neighbor summary. Currently it's still showing that 44 01:49.400 --> 01:49.920 we're not 45 01:49.920 --> 01:55.140 advertising any prefixes or networks out to that neighbor. So let's change that 46 01:55.140 --> 01:56.080 by going to the 47 01:56.080 --> 02:00.470 networking tab up on top under connectivity clicking on tier zero gateways. And WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 47 01:56.080 --> 02:00.470 networking tab up on top under connectivity clicking on tier zero gateways. And 48 02:00.470 --> 02:01.840 let's edit the details 49 02:01.840 --> 02:05.220 of our tier zero gateway. So we'll click on the three dots from the menu, we'll 50 02:05.220 --> 02:06.240 click on edit, 51 02:06.240 --> 02:10.460 and then we'll scroll down. And currently we're doing a route redistribution. 52 02:10.460 --> 02:10.800 And that's right 53 02:10.800 --> 02:14.510 down here. We did it previously with OSPF. So what we could do is we could just 54 02:14.510 --> 02:15.200 modify what 55 02:15.200 --> 02:18.130 we're redistributing and how we're redistributing those routes. And so to do 56 02:18.130 --> 02:18.880 that, I'm going to click 57 02:18.880 --> 02:23.100 right here on the route redistribution where it shows one. And currently we're 58 02:23.100 --> 02:24.560 redistributing the 59 02:24.560 --> 02:28.860 subnet 10 and subnet 20 via OSPF. And we want to modify that, click on the 60 02:28.860 --> 02:29.440 three dots, 61 02:29.440 --> 02:33.020 click on edit, and say, you know what, instead of doing it via OSPF, let's do WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 61 02:29.440 --> 02:33.020 click on edit, and say, you know what, instead of doing it via OSPF, let's do 62 02:33.020 --> 02:34.720 it via BGP. So now 63 02:34.720 --> 02:38.740 we're going to be redistributing via BGP. And as far as what we're redistribut 64 02:38.740 --> 02:38.960 ing, 65 02:38.960 --> 02:42.850 let's click right here on this one and just confirm what we're going to redist 66 02:42.850 --> 02:44.320 ribute. So this effectively 67 02:44.320 --> 02:48.400 says take any of your tier one subnets, which in our topology are the 10 10 68 02:48.400 --> 02:49.600 network and the 10 20 69 02:49.600 --> 02:54.400 network and redistribute them or advertise them via BGP. So with this in mind, 70 02:54.400 --> 02:56.080 we'll click on apply, 71 02:56.080 --> 03:00.130 we'll click on add here, we'll click on apply here, and then we'll click on WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 71 02:56.080 --> 03:00.130 we'll click on add here, we'll click on apply here, and then we'll click on 72 03:00.130 --> 03:01.440 save, and we'll scroll down, 73 03:01.440 --> 03:07.130 click on close. And now that we're advertising or supposedly advertising the 10 74 03:07.130 --> 03:08.640 10 and 10 20 subnets 75 03:08.640 --> 03:12.970 via BGP, let's go back here to our external BGP router, which has debugging 76 03:12.970 --> 03:14.000 enabled. And this is 77 03:14.000 --> 03:17.660 verify whether or not we see those console messages about those routes showing 78 03:17.660 --> 03:18.800 up. So here we are back 79 03:18.800 --> 03:22.750 at our router and sure enough, here we have console messages saying, hey, 80 03:22.750 --> 03:24.080 updating BGP 10 10 zero, 81 03:24.080 --> 03:28.720 the 24 bit network via the next top at 192 once you date 1.61. And that's our 82 03:28.720 --> 03:30.160 edge transport node edge WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 82 03:28.720 --> 03:30.160 edge transport node edge 83 03:30.160 --> 03:34.090 one. We also have an update regarding the 10 20 network that we've learned 84 03:34.090 --> 03:34.960 about via BGP with 85 03:34.960 --> 03:39.560 the next top of 192 once state one dot 61. So now we hit the upper key a couple 86 03:39.560 --> 03:40.800 times into show IP 87 03:40.800 --> 03:44.780 BGP summary is showing us that we have those two neighbors still and we've 88 03:44.780 --> 03:46.000 learned two prefixes 89 03:46.000 --> 03:49.620 or two networks from each of them. So in the case that we're learning the same 90 03:49.620 --> 03:50.560 routes, in this case, 91 03:50.560 --> 03:54.760 is the 10 10 and 10 20 networks, and we're learning it, the router 673 is 92 03:54.760 --> 03:56.240 learning it from both edge 93 03:56.240 --> 03:59.730 one and edge two, which one of those routes is it going to use? And we can see 94 03:59.730 --> 04:00.640 the details for that WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 94 03:59.730 --> 04:00.640 the details for that 95 04:00.640 --> 04:06.070 on the Cisco device by doing a show IP BGP space in the question mark, and I'm 96 04:06.070 --> 04:07.120 gonna say IP V4 97 04:07.680 --> 04:11.220 space and the question mark, unicast, the fancy way of saying please show me 98 04:11.220 --> 04:12.640 the BGP table for 99 04:12.640 --> 04:16.640 IP V4 on this is good advice. So here what is showing it on the far left, we 100 04:16.640 --> 04:17.680 have the asterisk, 101 04:17.680 --> 04:20.490 which means is the valid route. And then furthermore, we have a little greater 102 04:20.490 --> 04:21.600 than some more right here. 103 04:21.600 --> 04:24.800 That means it's the best route. So what that says is this route to the 10 10 104 04:24.800 --> 04:25.840 zero network is the 105 04:25.840 --> 04:30.890 best route through dot 61. And this route right here to the 10 20 zero network WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 105 04:25.840 --> 04:30.890 best route through dot 61. And this route right here to the 10 20 zero network 106 04:30.890 --> 04:31.520 with the next top of 107 04:31.520 --> 04:35.650 192 once state one 61 is the best route. I also have my debugging still enabled 108 04:35.650 --> 04:36.640 . Let me turn that off 109 04:36.640 --> 04:39.740 with an undibug all and let me have the up here a couple times. Let's take a 110 04:39.740 --> 04:40.400 look at the routes 111 04:40.400 --> 04:43.630 again. So what's happening is edge one, which is the active device in our 112 04:43.630 --> 04:45.040 active standby pair. 113 04:45.040 --> 04:51.030 It's advertising a path of 777 meaning this route came from a ton of system 777 114 04:51.030 --> 04:51.920 . And the other router 115 04:51.920 --> 04:57.570 dot 62, which is edge two pre-pended that same autonomous system three more 116 04:57.570 --> 04:58.480 times just to make 117 04:58.480 --> 05:01.880 it look worse. And that way, as we receive those routes, we'll say, Hey, you WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 117 04:58.480 --> 05:01.880 it look worse. And that way, as we receive those routes, we'll say, Hey, you 118 05:01.880 --> 05:02.720 know what, I've got 119 05:02.720 --> 05:06.500 the same route from these two peers, I'm going to choose the one that has the 120 05:06.500 --> 05:07.360 least number of 121 05:07.360 --> 05:10.120 autonomous systems they had to cross through. And that's why right here, we're 122 05:10.120 --> 05:10.800 using this is our 123 05:10.800 --> 05:14.910 best route coming from edge one. And the other routes going from edge two are 124 05:14.910 --> 05:16.080 not considered as 125 05:16.080 --> 05:19.710 good because they have a longer as path. So right here from this multi layer 126 05:19.710 --> 05:21.200 switch, if we did a ping 127 05:21.200 --> 05:26.980 to 10 dot 10 dot zero dot 10. And let me also make sure that is up and running. 128 05:26.980 --> 05:27.440 So that's this 129 05:27.440 --> 05:31.790 little VM right here, 10 10 zero 10, because we now have reach a billion WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 129 05:27.440 --> 05:31.790 little VM right here, 10 10 zero 10, because we now have reach a billion 130 05:31.790 --> 05:33.200 routing information on this 131 05:33.200 --> 05:37.010 BGP speaker, we should be able to forward traffic and have it routed down to 132 05:37.010 --> 05:38.400 that little VM. So let's 133 05:38.400 --> 05:42.990 verify that by bringing a little terminal window. This is a VM number one. And 134 05:42.990 --> 05:44.800 if we do a ping to 192 135 05:44.800 --> 05:50.610 dot 168 dot 1 dot 121, that should work fantastic. We should also be able to 136 05:50.610 --> 05:52.160 ping from here from the 137 05:52.160 --> 05:57.180 external BGP router down to 10 10 0 10. So put some there and that's working 138 05:57.180 --> 05:58.000 great.