WEBVTT 1 00:00.000 --> 00:04.080 Alright, so we're going to jump into the lab and configure rapid spanning tree 2 00:04.080 --> 00:04.540 and the 3 00:04.540 --> 00:09.080 topology is what we've already used several times in this course up till now. 4 00:09.080 --> 00:12.450 We have switches three, four and five in a triangle and switch three is the 5 00:12.450 --> 00:12.880 root. 6 00:12.880 --> 00:18.440 So let's go ahead and log into the lab here and we're on switch three. 7 00:18.440 --> 00:22.890 If I do a show spanning tree, I always remember that the mode by default on a 8 00:22.890 --> 00:23.640 Cisco iOSXE 9 00:23.640 --> 00:27.540 switch is that we're running traditional spanning tree and protocol IEEE is 10 00:27.540 --> 00:29.320 what tells us that. 11 00:29.320 --> 00:32.700 It doesn't appear to directly tell us that, but this is going to change when we WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 11 00:29.320 --> 00:32.700 It doesn't appear to directly tell us that, but this is going to change when we 12 00:32.700 --> 00:33.240 configure 13 00:33.240 --> 00:34.240 rapid. 14 00:34.240 --> 00:35.240 Let's go and do that. 15 00:35.240 --> 00:39.480 I'm going to do a config T and the command is simply spanning tree mode and 16 00:39.480 --> 00:40.240 then we'll 17 00:40.240 --> 00:41.480 see our three options here. 18 00:41.480 --> 00:45.830 We have our PVST, which is the default MST, which we're going to cover later 19 00:45.830 --> 00:46.440 and then 20 00:46.440 --> 00:52.680 rapid PVST and the plus is implied in that, but it's rapid PVST plus. 21 00:52.680 --> 00:58.360 But by enabling this, I now have done a major change to my spanning tree top 22 00:58.360 --> 00:59.200 ology. 23 00:59.200 --> 01:03.890 So if I do a show spanning tree again, we do see that the protocols now are STP WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 23 00:59.200 --> 01:03.890 So if I do a show spanning tree again, we do see that the protocols now are STP 24 01:03.890 --> 01:04.560 for rapid 25 01:04.560 --> 01:05.800 spanning tree. 26 01:05.800 --> 01:09.200 So I'm going to go to the other switches in my topology here, including switch 27 01:09.200 --> 01:09.680 four and 28 01:09.680 --> 01:16.720 do the same command spanning tree mode rapid and switch five as well. 29 01:16.720 --> 01:21.760 Use the abbreviation here, spanning mode rapid. 30 01:21.760 --> 01:26.320 So when I do my show spanning tree, we'll probably see that the ports are 31 01:26.320 --> 01:27.080 already in 32 01:27.080 --> 01:28.080 forwarding. 33 01:28.080 --> 01:31.660 So we have majorly disruptive change in theory and yet because of rapid's WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 33 01:28.080 --> 01:31.660 So we have majorly disruptive change in theory and yet because of rapid's 34 01:31.660 --> 01:32.320 nature and the 35 01:32.320 --> 01:36.100 ability to on point to point links, we see that listed right here on point to 36 01:36.100 --> 01:36.880 point links, 37 01:36.880 --> 01:40.980 we can use negotiation to immediately figure out, okay, you're my root switch 38 01:40.980 --> 01:41.480 or switch 39 01:41.480 --> 01:42.480 port. 40 01:42.480 --> 01:46.960 And so now switch three knows to have that into forwarding. 41 01:46.960 --> 01:54.600 And so where it looks like we're actually, where are we blocking show spanning 42 01:54.600 --> 01:54.880 tree. 43 01:54.880 --> 01:59.360 We're blocking here switch four is blocking on three slash one. 44 01:59.360 --> 02:04.820 So if we go back to our topology, the reason for that is because while I WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 44 01:59.360 --> 02:04.820 So if we go back to our topology, the reason for that is because while I 45 02:04.820 --> 02:06.400 configured switch 46 02:06.400 --> 02:11.250 three with a priority of four thousand, making it the root, I did not configure 47 02:11.250 --> 02:11.920 anything 48 02:11.920 --> 02:13.320 on switch four. 49 02:13.320 --> 02:17.040 So switch four and switch five have a MAC address battle here, switch four 50 02:17.040 --> 02:17.720 apparently 51 02:17.720 --> 02:21.640 lost that because it's blocking this port right here. 52 02:21.640 --> 02:24.200 And so that is our current topology. 53 02:24.200 --> 02:26.880 So rapid figured that out really, really quickly. 54 02:26.880 --> 02:32.640 Now we'll also notice that even though Cisco is well, they're using BLK for WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 54 02:26.880 --> 02:32.640 Now we'll also notice that even though Cisco is well, they're using BLK for 55 02:32.640 --> 02:33.680 blocking, they 56 02:33.680 --> 02:37.760 probably should be using DIS for discarding, but they didn't update the status 57 02:37.760 --> 02:38.320 in iOS X 58 02:38.320 --> 02:41.280 E. It still shows BLK for blocking. 59 02:41.280 --> 02:45.100 And that's one of the reasons why you probably noticed throughout this skill, I 60 02:45.100 --> 02:45.680 still refer 61 02:45.680 --> 02:46.760 to it as blocking. 62 02:46.760 --> 02:51.270 Many people refer to it as blocking, even though technically it's in a disc 63 02:51.270 --> 02:52.360 arding state. 64 02:52.360 --> 02:55.520 We do however, see under role, this alternate port. 65 02:55.520 --> 02:57.640 Now this was there before rapid. 66 02:57.640 --> 03:01.560 If we disabled rapid and looked at, you know, traditional spanning tree, this WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 66 02:57.640 --> 03:01.560 If we disabled rapid and looked at, you know, traditional spanning tree, this 67 03:01.560 --> 03:02.280 would still 68 03:02.280 --> 03:03.720 say alternate. 69 03:03.720 --> 03:07.330 And that's simply because they're not going to distinguish between those when 70 03:07.330 --> 03:07.800 we're not 71 03:07.800 --> 03:09.480 running rapid spanning tree. 72 03:09.480 --> 03:12.680 But now that we are running rapid spanning tree, we do see that I've got 73 03:12.680 --> 03:13.480 another uplink 74 03:13.480 --> 03:14.920 option here. 75 03:14.920 --> 03:16.200 It is blocking. 76 03:16.200 --> 03:20.660 But if I were to take down my root port, let's do a config T and gig zero or 77 03:20.660 --> 03:21.440 one zero. 78 03:21.440 --> 03:26.600 And I shut this down and then very quickly do a show spanning tree. 79 03:26.600 --> 03:32.210 We'll see that that gig three slash one, which was right here, was my alternate WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 79 03:26.600 --> 03:32.210 We'll see that that gig three slash one, which was right here, was my alternate 80 03:32.210 --> 03:32.600 port 81 03:32.600 --> 03:37.470 and blocking is already the root port in an affording state is able to do that 82 03:37.470 --> 03:38.160 because 83 03:38.160 --> 03:42.720 of rapid and because of the fact that it was designated as an alternate port. 84 03:42.720 --> 03:45.760 So we're going to do a no shut on that. 85 03:45.760 --> 03:49.760 And again, it is a beautiful thing to be working with rapid after working with 86 03:49.760 --> 03:50.300 traditional 87 03:50.300 --> 03:54.110 spanning tree for so long because pretty much as soon as I do a no shut and the 88 03:54.110 --> 03:54.520 port is 89 03:54.520 --> 03:58.670 online, we're back to our original spanning tree topology, which is where we 90 03:58.670 --> 03:59.160 want to 91 03:59.160 --> 04:00.160 be. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 91 03:59.160 --> 04:00.160 be. 92 04:00.160 --> 04:01.260 So let's go ahead here. 93 04:01.260 --> 04:03.740 We're on switch four. 94 04:03.740 --> 04:05.480 Let's just go ahead and do a debug. 95 04:05.480 --> 04:09.080 This is a great command debug spanning tree events. 96 04:09.080 --> 04:12.630 We've used this command before, but this is going to allow me to see things 97 04:12.630 --> 04:13.200 like BPD 98 04:13.200 --> 04:14.920 is being sent and such. 99 04:14.920 --> 04:20.990 But in this case, I'm going to get onto my interface gig one zero, which is my 100 04:20.990 --> 04:21.460 root 101 04:21.460 --> 04:22.740 port, by the way. 102 04:22.740 --> 04:24.620 And so I'm going to shut this down support. 103 04:24.620 --> 04:25.620 I just shut down. 104 04:25.620 --> 04:28.980 Actually, we just want to look at things from a debug perspective. 105 04:28.980 --> 04:33.660 So when I do a shutdown on this, we're going to notice some things here. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 105 04:28.980 --> 04:33.660 So when I do a shutdown on this, we're going to notice some things here. 106 04:33.660 --> 04:34.940 All right. 107 04:34.940 --> 04:40.740 So let's go ahead and undi bug all so we don't keep getting debug messages. 108 04:40.740 --> 04:42.100 Notice these debug messages. 109 04:42.100 --> 04:43.700 Well, what happened here? 110 04:43.700 --> 04:46.520 Well, rapid spanning tree is saying, hey, we're updating the roles. 111 04:46.520 --> 04:49.200 Our root port is now down. 112 04:49.200 --> 04:51.760 And now gig three slash one is now the root port. 113 04:51.760 --> 04:54.960 And then we generate a topology change trap. 114 04:54.960 --> 04:56.760 So it happens very, very quickly. 115 04:56.760 --> 05:00.610 And if we turn on the timestamp on the debug messages, we'd see that that all WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 115 04:56.760 --> 05:00.610 And if we turn on the timestamp on the debug messages, we'd see that that all 116 05:00.610 --> 05:01.240 happened 117 05:01.240 --> 05:02.800 back to back to back. 118 05:02.800 --> 05:05.870 So it's pretty fun to be able to see some of these messages fly around using 119 05:05.870 --> 05:08.840 our debug. 120 05:08.840 --> 05:11.520 Now I'm just going to get onto another interface. 121 05:11.520 --> 05:14.240 This interface is not connecting to another switch. 122 05:14.240 --> 05:18.290 So I'm just going to do a no shut on this interface and then do a show spanning 123 05:18.290 --> 05:18.880 tree. 124 05:18.880 --> 05:20.280 What happens on a port? 125 05:20.280 --> 05:22.160 Whoops, let's wait until it's actually online. 126 05:22.160 --> 05:23.160 Oh, it was online. 127 05:23.160 --> 05:24.160 There it is. 128 05:24.160 --> 05:26.700 So we see that it's in a blocking state. 129 05:26.700 --> 05:29.520 State role is designated. 130 05:29.520 --> 05:32.280 But notice it doesn't say listening here. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 130 05:29.520 --> 05:32.280 But notice it doesn't say listening here. 131 05:32.280 --> 05:35.480 So if I do it again, we should see that it's in the learning state now. 132 05:35.480 --> 05:38.440 But yeah, we're not in again, Cisco doesn't say discarding. 133 05:38.440 --> 05:39.920 It says blocking. 134 05:39.920 --> 05:44.310 But it did not actually list out listening, even though it did it for 15 135 05:44.310 --> 05:45.040 seconds. 136 05:45.040 --> 05:46.880 So then transition to learning. 137 05:46.880 --> 05:50.430 And by now it's probably, well, still in learning, but it's going to very 138 05:50.430 --> 05:51.400 quickly transition 139 05:51.400 --> 05:52.920 over to forwarding at this point. 140 05:52.920 --> 05:53.920 There we go. 141 05:53.920 --> 05:55.440 So why did that take 30 full seconds? 142 05:55.440 --> 06:00.460 Well, because again, even though the port is in an upstate there up status, WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 142 05:55.440 --> 06:00.460 Well, because again, even though the port is in an upstate there up status, 143 06:00.460 --> 06:01.080 there is 144 06:01.080 --> 06:02.840 no switch on the other side. 145 06:02.840 --> 06:05.440 If there's no switch on the other side, there's no BP to use. 146 06:05.440 --> 06:07.360 I can't negotiate with anybody. 147 06:07.360 --> 06:11.380 And so if this was a laptop, this would still take 30 seconds, which is why we 148 06:11.380 --> 06:11.760 want to make 149 06:11.760 --> 06:16.510 sure that we are indeed configuring that as an edge port, even in the rapid 150 06:16.510 --> 06:17.200 world. 151 06:17.200 --> 06:21.720 In fact, in the rapid spanning tree world, as we said, that's even more 152 06:21.720 --> 06:22.840 important. 153 06:22.840 --> 06:24.040 So how do we do that? 154 06:24.040 --> 06:28.800 Well, for on this interface, we might do a switch mode access to make it an 155 06:28.800 --> 06:29.960 access mode. 156 06:29.960 --> 06:31.520 I could configure it globally. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 156 06:29.960 --> 06:31.520 I could configure it globally. 157 06:31.520 --> 06:33.080 I could configure it here. 158 06:33.080 --> 06:34.240 So spanning tree. 159 06:34.240 --> 06:38.440 Now again, I can do port fast. 160 06:38.440 --> 06:42.870 Usually that would be the command, but on iOS, this virtual iOS, we do have to 161 06:42.870 --> 06:43.520 include 162 06:43.520 --> 06:45.160 the phrase edge here. 163 06:45.160 --> 06:48.730 But now it's going to not send topology changes and it would come up very, very 164 06:48.730 --> 06:49.400 quickly. 165 06:49.400 --> 06:53.440 I could do a shutdown on this port, do my no shut. 166 06:53.440 --> 06:59.270 And rather than sitting here and waiting for 30 seconds, we should see that it 167 06:59.270 --> 06:59.880 's immediately 168 06:59.880 --> 07:02.000 in the forwarding state and it is. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 168 06:59.880 --> 07:02.000 in the forwarding state and it is. 169 07:02.000 --> 07:05.880 And we see over here on the right that it indicates its point to point edge. 170 07:05.880 --> 07:06.960 So very good. 171 07:06.960 --> 07:11.930 That is how we configure our port type edge, which is still using Cisco's port 172 07:11.930 --> 07:13.320 fast command. 173 07:13.320 --> 07:16.960 Now lastly, I would never recommend doing this in public, but just to solidify 174 07:16.960 --> 07:17.240 some 175 07:17.240 --> 07:20.920 of these concepts, I say in public, but in production, I meant to say, yeah, 176 07:20.920 --> 07:21.320 don't do 177 07:21.320 --> 07:22.320 it in public. 178 07:22.320 --> 07:23.800 Don't want anybody judging you. 179 07:23.800 --> 07:29.560 If I get on to interface gig three slash one here, I do have this command. 180 07:29.560 --> 07:32.080 Clicking tree link type. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 180 07:29.560 --> 07:32.080 Clicking tree link type. 181 07:32.080 --> 07:35.840 And then we see I can configure this to be a shared link. 182 07:35.840 --> 07:40.470 If I look at my topology, we see gig three slash one here is the blocking port 183 07:40.470 --> 07:41.080 towards 184 07:41.080 --> 07:47.040 switch five, which means that it can't actually run in a rapid spanning tree if 185 07:47.040 --> 07:48.040 I configure 186 07:48.040 --> 07:49.880 it to be shared. 187 07:49.880 --> 07:51.520 So let's do it. 188 07:51.520 --> 07:52.520 Configure it as shared. 189 07:52.520 --> 07:58.670 I'm going to shut this link down and I'll get on to switch five on the other 190 07:58.670 --> 07:59.520 side. 191 07:59.520 --> 08:03.200 Also interface gig three slash one, shut it down. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 191 07:59.520 --> 08:03.200 Also interface gig three slash one, shut it down. 192 08:03.200 --> 08:05.240 And let's do a no shut and watch this process. 193 08:05.240 --> 08:09.240 So no shot on this side, no shot on this side. 194 08:09.240 --> 08:18.060 And if I say show spanning tree on the downstream switch, notice, oh, this is 195 08:18.060 --> 08:19.520 switch four still 196 08:19.520 --> 08:23.800 let's get to switch five, do show spanning tree. 197 08:23.800 --> 08:27.830 So we notice that it's in a blocking state right now, because it's going 198 08:27.830 --> 08:29.040 through listening 199 08:29.040 --> 08:30.860 and learning. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 199 08:29.040 --> 08:30.860 and learning. 200 08:30.860 --> 08:34.080 And so in a moment here, it'll transition to learning and there we go. 201 08:34.080 --> 08:38.320 So it knows that switch four or switch four rather is not running rapid 202 08:38.320 --> 08:39.520 spanning tree because 203 08:39.520 --> 08:40.520 it's a shared port. 204 08:40.520 --> 08:43.480 It can't assume that there's a switch on the other side and therefore it's not 205 08:43.480 --> 08:43.880 even going 206 08:43.880 --> 08:45.840 to try to negotiate switch five. 207 08:45.840 --> 08:49.560 Meanwhile says, well, I couldn't negotiate, but nobody's negotiating with me. 208 08:49.560 --> 08:53.710 And so this is why we keep saying that rapid is entirely relying on those 209 08:53.710 --> 08:54.720 negotiations. 210 08:54.720 --> 08:58.000 And so long as we're able to negotiate, we're good to go. 211 08:58.000 --> 09:00.640 But if we can't negotiate, then we're just going to go right back to our old WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 211 08:58.000 --> 09:00.640 But if we can't negotiate, then we're just going to go right back to our old 212 09:00.640 --> 09:01.240 way of doing 213 09:01.240 --> 09:04.700 things by transitioning through listening and learning, just keeping in mind 214 09:04.700 --> 09:05.440 that listening 215 09:05.440 --> 09:08.880 is now discarding, which Cisco shows as blocking. 216 09:08.880 --> 09:12.040 But either way, listening will no longer show up in rapid spanning tree.