1 00:00:00,950 --> 00:00:07,370 More rapid spending is backward compatible with a little to one D and in the same way Rapide previous 2 00:00:07,370 --> 00:00:11,770 t is compatible with previous t on switch 3. 3 00:00:11,930 --> 00:00:17,840 These ports were converging quickly because we're using rapid spending tree between switch 1 2 and 3 4 00:00:18,540 --> 00:00:22,670 but the links to switch for are stored using Peavey's. 5 00:00:22,910 --> 00:00:26,990 So what you'll notice is it takes longer for those links to converge 6 00:00:30,170 --> 00:00:35,930 show spanning tree as an example shows me that the ports are now forwarding but they've taken a lot 7 00:00:35,930 --> 00:00:40,930 longer to converge than they would have with Reppert Peavey's cheat. 8 00:00:41,060 --> 00:00:48,170 So once again on interface gigabit zero one all know port shows spanning tree. 9 00:00:48,170 --> 00:00:49,790 We can already see that gigabit. 10 00:00:49,820 --> 00:00:59,000 0 1 is the root port and is forwarding and gigabit 0 0 is an alternate port and is blocking However 11 00:00:59,150 --> 00:01:04,780 other ports such as gigabit 0 2 and 0 3 are still learning. 12 00:01:05,060 --> 00:01:11,070 So it's going to take time for these ports to move to the forwarding state. 13 00:01:11,120 --> 00:01:15,830 You can see they have now moved to the forwarding state but that's because there is an older version 14 00:01:15,830 --> 00:01:24,520 of spanning tree negotiated between switch three and switch for switch three once again is using Reppert 15 00:01:24,520 --> 00:01:27,400 previous the switch for however 16 00:01:31,900 --> 00:01:37,330 is using per villans spanning tree not rapid Peavey's T. 17 00:01:37,420 --> 00:01:43,720 So triple is shown in the output whereas once again on switch 3 it's Rapide previous t. 18 00:01:44,090 --> 00:01:49,360 So that is backward compatibility between rapid previous t and previous t. 19 00:01:49,740 --> 00:01:55,110 But the convergence will be slow between rapid previous and previous TB because of backward compatibility 20 00:01:55,650 --> 00:02:03,650 and within the previous part of your network let's have a look at the capture. 21 00:02:03,690 --> 00:02:07,290 So this is on switch three as advertised to the hub. 22 00:02:08,150 --> 00:02:15,870 And what you can see here is that the protocol used a spanning tree not rapid spending tree and that's 23 00:02:15,870 --> 00:02:22,730 because switch three has negotiated to use spending tree with switch for not rapid spending tree. 24 00:02:22,730 --> 00:02:30,050 So in the output once again it's spanning tree protocol not rapid spending tree protocol path cost route 25 00:02:30,070 --> 00:02:35,850 identify and bridge identify are shown here but it's negotiated to use the older version of spending 26 00:02:35,850 --> 00:02:38,550 tree even though this document is old. 27 00:02:38,580 --> 00:02:46,470 It provides a great explanation of rapid spending tree or ADA to the one w and multiple spending tree 28 00:02:46,730 --> 00:02:52,740 or ADA to that one yes you can find this document as part of the course or you can search in Google 29 00:02:52,740 --> 00:02:59,900 as an example for the Cisco Avot network infrastructure this document explains the evolution of spending 30 00:02:59,900 --> 00:03:07,820 tree and house spending tree has existed for a long time in an unchanged format that has been enhanced 31 00:03:07,880 --> 00:03:13,150 through the use of rapid spending tree and multiple spending tree it a two to one. 32 00:03:13,220 --> 00:03:20,000 Once again is the initial version of spending tree and was designed to stop loops in switched or bridged 33 00:03:20,090 --> 00:03:21,310 networks. 34 00:03:21,320 --> 00:03:28,850 It was very difficult to get fast convergence with Ada to 1 D. 35 00:03:28,860 --> 00:03:35,250 One of the problems with Ada 3:01 D is that it uses time as supports go from blocking to listening to 36 00:03:35,250 --> 00:03:40,540 learning to forwarding and that process can take 50 seconds. 37 00:03:40,740 --> 00:03:49,530 When a port comes up as an example it goes from listening to learning to forwarding which takes 30 seconds. 38 00:03:49,570 --> 00:03:56,870 Now Cisco enhanced it through one D in the 1990s by introducing uplink Foster backbone first and port 39 00:03:56,870 --> 00:03:59,650 fust for the CCN course today. 40 00:03:59,780 --> 00:04:03,160 You don't need to know about uplink fast or backbone fast. 41 00:04:03,320 --> 00:04:05,270 You can just ignore those. 42 00:04:05,320 --> 00:04:13,460 The important one to remember is port fast or ports which are ports connected to and a use of devices 43 00:04:13,460 --> 00:04:21,280 such as PCs or servers that transition immediately to the forwarding state. 44 00:04:21,410 --> 00:04:26,270 The trouble e incorporated most of these concepts into two standards. 45 00:04:26,570 --> 00:04:33,110 Rapid spending tree and multiple spending tree with these protocols convergence time as were a lot quicker 46 00:04:33,770 --> 00:04:39,420 Cisco have taken that those protocols and enhanced PV is ti. 47 00:04:39,440 --> 00:04:43,930 So today we have Rapide previous to t and Cisco switches. 48 00:04:44,120 --> 00:04:54,630 So as an example on the switch we can type spending tree mode and we can specify Reppert previous TTY 49 00:04:55,140 --> 00:05:03,240 or MSCE the industry standard version of rapid spending tree only has one root in the entire topology 50 00:05:03,840 --> 00:05:10,880 where as a Reppert Peavey's T gives you a route on a per villaine basis. 51 00:05:11,160 --> 00:05:18,390 So it's a lot better than pure Reppert spending tree or editor one w multiple spending tree doesn't 52 00:05:18,390 --> 00:05:26,940 give you a route per Villon but it gives you the ability to associate multiple villans to a spanning 53 00:05:26,940 --> 00:05:28,000 tree root. 54 00:05:28,200 --> 00:05:32,680 So you could say in a campus network as an example that villans 1 to 100. 55 00:05:32,690 --> 00:05:34,330 So which one is the root. 56 00:05:34,410 --> 00:05:38,610 But villans 101 to 200 have switched to as the root.