1 00:00:00,630 --> 00:00:08,670 In this example, we've got two switches and four routers which are acting as PCs in the topology. 2 00:00:09,030 --> 00:00:14,670 We've also got a hub which I'm going to use to capture traffic using Wireshark. 3 00:00:15,330 --> 00:00:19,980 These devices have just booted up, so they have no configuration. 4 00:00:20,490 --> 00:00:29,850 On the first switch, I'll give the switch a hostname of one and on the second switch, give it a hostname 5 00:00:29,850 --> 00:00:30,750 of S2. 6 00:00:32,990 --> 00:00:33,860 Show. 7 00:00:35,610 --> 00:00:36,420 VLAN. 8 00:00:37,530 --> 00:00:43,770 At the moment we only have one ethernet of VLAN configured VLAN one. 9 00:00:44,190 --> 00:00:47,460 All ports in the switch are configured in that VLAN. 10 00:00:47,880 --> 00:00:54,720 Cisco switches also have some older VLANs by default 1002, three, four and five, which were used 11 00:00:54,720 --> 00:00:57,180 previously for FTI and token ring. 12 00:00:57,390 --> 00:01:00,630 Those VLANs are not used any more today. 13 00:01:03,030 --> 00:01:04,620 Switch to shows something similar. 14 00:01:04,620 --> 00:01:06,150 So show vlan brief. 15 00:01:07,020 --> 00:01:08,490 We have vlan one. 16 00:01:08,670 --> 00:01:11,040 All ports are configured in VLAN one. 17 00:01:11,430 --> 00:01:14,280 Here's rather one which is acting as our PC. 18 00:01:15,300 --> 00:01:21,480 I'm going to configure the first Ethernet interface with an IP address of ten 111. 19 00:01:23,470 --> 00:01:25,240 Slash 24 musk and I'll no. 20 00:01:25,260 --> 00:01:26,650 Shut the interface. 21 00:01:29,100 --> 00:01:32,490 On rather to do something similar. 22 00:01:33,850 --> 00:01:34,020 No. 23 00:01:34,020 --> 00:01:37,950 Shut the interface given an IP address of ten 112. 24 00:01:40,870 --> 00:01:47,230 So without any further configuration, we should be able to ping between rather one and rather two. 25 00:01:47,830 --> 00:01:52,030 Notice rather to can ping write a one and write a one. 26 00:01:52,120 --> 00:01:55,150 Can ping rather to the switches. 27 00:01:55,150 --> 00:01:57,610 Just have a default config. 28 00:01:59,440 --> 00:02:02,770 All ports on the switches are in VLAN one. 29 00:02:03,600 --> 00:02:09,570 We can see that by using the command show interface gigabit or zero zero switch port. 30 00:02:10,500 --> 00:02:15,870 The support gigabyte zero zero is using administrative mode. 31 00:02:15,870 --> 00:02:22,440 Dynamic auto operational mode at the moment is static access negotiation of trunking is on. 32 00:02:22,440 --> 00:02:24,330 In other words, FTP is enabled. 33 00:02:24,330 --> 00:02:27,960 But at the moment because there is no switch to negotiate with. 34 00:02:28,840 --> 00:02:31,870 The port is in VLAN one the default VLAN. 35 00:02:32,380 --> 00:02:36,880 Now we can see the traffic by doing a CAPTCHA using Wireshark. 36 00:02:41,010 --> 00:02:42,420 Various traffic is seen here. 37 00:02:42,420 --> 00:02:49,770 We've got a spanning tree beeped you being sent by the switch we can see Cisco discovery protocol messages 38 00:02:49,890 --> 00:02:56,670 being sent by the switch as well, showing the switch port, the platform and other information. 39 00:02:58,790 --> 00:03:03,800 But what I'd like you to see is all traffic is Ethernet frames. 40 00:03:03,980 --> 00:03:08,990 There is no 2 to 1 queue tagging on these frames. 41 00:03:09,530 --> 00:03:12,860 Let's do a search for ICMP traffic. 42 00:03:12,890 --> 00:03:15,380 At the moment there is no ICMP traffic. 43 00:03:16,550 --> 00:03:21,920 I'll get rather one to ping root of two and notice we see the ICMP traffic. 44 00:03:24,130 --> 00:03:28,030 What you'll notice is we have the source Mac address of router one. 45 00:03:28,940 --> 00:03:30,350 Pinging routed to. 46 00:03:32,330 --> 00:03:35,930 Protocol type is IP version for source. 47 00:03:35,930 --> 00:03:38,120 IP version for addresses ten 111. 48 00:03:38,150 --> 00:03:40,610 Destination IP Addresses ten 112. 49 00:03:42,690 --> 00:03:50,130 It's a standard Ethernet frame encapsulating IP and ICMP. 50 00:03:50,430 --> 00:03:54,810 In this case, it's an echo and the reply is an echo reply. 51 00:03:55,510 --> 00:03:59,320 There is no Ethernet tagging on this frame at all. 52 00:03:59,410 --> 00:04:02,320 It's a standard Ethernet frame. 53 00:04:02,350 --> 00:04:04,960 There is no concept of VLAN either. 54 00:04:04,990 --> 00:04:08,740 No VLAN information is transmitted on the frames. 55 00:04:10,240 --> 00:04:18,040 Even the other frames such as CDP don't show any VLAN information whatsoever. 56 00:04:18,800 --> 00:04:20,050 We'll stop that capture. 57 00:04:21,860 --> 00:04:25,280 This is an access port and this is an access port by default. 58 00:04:25,490 --> 00:04:28,490 The same will be true on switch two. 59 00:04:29,120 --> 00:04:35,840 I'll configure router three with an IP address of ten. 60 00:04:35,840 --> 00:04:37,040 One one, two, three. 61 00:04:41,160 --> 00:04:44,970 Shut the interface and I'll do something similar on right of four. 62 00:04:51,080 --> 00:04:51,650 Shut. 63 00:04:52,040 --> 00:04:54,020 IP address ten 114. 64 00:05:00,460 --> 00:05:02,590 Ken wrote for ping router three. 65 00:05:02,830 --> 00:05:04,120 Acting as host three. 66 00:05:04,150 --> 00:05:05,110 Yes, it can. 67 00:05:06,490 --> 00:05:07,780 Start a CAPTCHA here. 68 00:05:09,830 --> 00:05:18,170 We can see various traffic types being captured, including once again CDP en route of three, helping 69 00:05:18,180 --> 00:05:19,070 route of four. 70 00:05:21,090 --> 00:05:22,230 Ping succeeds. 71 00:05:24,210 --> 00:05:25,890 I'll filter for ICMP. 72 00:05:26,520 --> 00:05:30,750 And once again, you can see that this is a standard Ethernet frame. 73 00:05:30,810 --> 00:05:39,660 There is no information about VLANs contained in these frames, just standard Ethernet frames. 74 00:05:43,120 --> 00:05:48,540 So the PCs in the topology are unaware of any VLAN information. 75 00:05:48,550 --> 00:05:50,900 They are sending untagged frames. 76 00:05:50,920 --> 00:05:56,980 In other words, standard ethernet frames to the switches and the switches are sending untagged frames 77 00:05:56,980 --> 00:05:59,170 to the PCs. 78 00:05:59,890 --> 00:06:03,550 Now let's concentrate on switch one for the moment. 79 00:06:05,040 --> 00:06:13,050 I'm going to set the HTTP mode of the device to transparent, which means it won't try and synchronize 80 00:06:13,050 --> 00:06:15,720 VLAN information with the other switch. 81 00:06:17,260 --> 00:06:22,420 Shovlin once again shows us that we have one ethernet vlan configured. 82 00:06:23,650 --> 00:06:25,300 Let's create VLAN two. 83 00:06:26,370 --> 00:06:28,290 Show VLAN brief. 84 00:06:29,830 --> 00:06:36,340 We now have two ethernet vlans, but no ports are configured in VLAN two.