1 00:00:09,080 --> 00:00:17,240 Now in packet tracer we can see what actual packets look like on PC one PC on the left. 2 00:00:17,360 --> 00:00:24,590 I'm going to start typing to PC two, so I'm going to ping PC two from PC one. 3 00:00:25,700 --> 00:00:26,630 That works. 4 00:00:26,990 --> 00:00:30,440 But what I'll do now is go into simulation mode. 5 00:00:31,240 --> 00:00:34,090 And then I can do the ping again. 6 00:00:34,600 --> 00:00:41,680 Notice the packet is queued on PC one to be sent out of the router. 7 00:00:42,250 --> 00:00:44,590 That's what the packet looks like. 8 00:00:44,980 --> 00:00:47,650 It's got a source IP address of ten 112. 9 00:00:47,770 --> 00:00:48,880 Destination of ten. 10 00:00:48,880 --> 00:00:50,110 One, two, two. 11 00:00:50,920 --> 00:00:52,060 That's correct. 12 00:00:52,480 --> 00:00:56,530 The local IP address of this PC is ten 112. 13 00:00:56,830 --> 00:00:59,770 And we're sending traffic to the remote PC ten. 14 00:00:59,770 --> 00:01:01,380 One, two, two. 15 00:01:01,990 --> 00:01:04,360 I'm going to click capture forward. 16 00:01:04,390 --> 00:01:07,060 Packet is sent to the router. 17 00:01:07,820 --> 00:01:11,000 And this is what the packet looks like on the router. 18 00:01:11,420 --> 00:01:17,780 Inbound PD looks like this or inbound protocol data unit looks like this. 19 00:01:18,320 --> 00:01:23,810 Traffic is coming from PC one, going to PC two. 20 00:01:25,700 --> 00:01:28,550 But on outbound notice. 21 00:01:29,170 --> 00:01:35,800 Source IP address is customer writer one A destination IP address is customer router two. 22 00:01:37,720 --> 00:01:49,060 And on egress or outbound out of the router, we now have a GRC header and a encapsulated IP header. 23 00:01:49,300 --> 00:01:58,780 So the original inbound protocol data unit or inbound information, this IP information is encapsulated 24 00:01:58,810 --> 00:02:01,990 inside an external header. 25 00:02:02,560 --> 00:02:10,509 So going right to the top Ethernet to this is an Ethernet, a link between customer rather one and ISP 26 00:02:10,509 --> 00:02:10,990 one. 27 00:02:12,610 --> 00:02:24,460 External IP header is thus then encapsulated in that we have degree and we have the encapsulated original 28 00:02:24,460 --> 00:02:25,540 IP packet. 29 00:02:26,080 --> 00:02:27,580 Click capture forward. 30 00:02:28,370 --> 00:02:29,690 On this, rather. 31 00:02:31,160 --> 00:02:33,200 Something very similar happens. 32 00:02:33,680 --> 00:02:40,700 Notice inbound Purdue contains the outer headers of customer right of one talking to customer out of 33 00:02:40,700 --> 00:02:48,700 two with the encapsulated original IP packet outbound, something very similar is going to be used, 34 00:02:48,710 --> 00:02:52,190 but what you'll notice is the MAC addresses will change. 35 00:02:52,490 --> 00:03:03,500 So from one interface to another on the router, the source Mac address will change because we're sending 36 00:03:03,500 --> 00:03:11,690 the traffic across a separate Ethernet link when it gets to this router, something very similar. 37 00:03:13,040 --> 00:03:19,220 All that happens here is the Mac addresses are being changed. 38 00:03:20,270 --> 00:03:23,300 The information changes, but we won't worry too much about that. 39 00:03:25,100 --> 00:03:31,670 The big thing to note is the writers are writing based on the external IP headers. 40 00:03:32,810 --> 00:03:37,160 It gets to write a three something very similar inbound. 41 00:03:37,160 --> 00:03:45,950 Purdue still using these IP addresses and so is the outbound Purdue or Protocol Data Unit. 42 00:03:46,370 --> 00:03:51,620 When it gets to this router, however, things change. 43 00:03:52,400 --> 00:04:01,970 So on this router inbound Purdue has the eight network IP addresses and the encapsulated. 44 00:04:02,870 --> 00:04:09,440 IP addresses, but the outbound Purdue has the jury information stripped. 45 00:04:09,920 --> 00:04:11,960 So what you'll notice is inbound. 46 00:04:11,960 --> 00:04:19,910 We have these IP addresses, we have the jury header and we have the internal IP packet information. 47 00:04:20,360 --> 00:04:27,410 But outbound there is no geo re and we don't see Network eight in the list of IP addresses. 48 00:04:27,830 --> 00:04:38,720 The outer headers have been removed from the packet and that's what the client is going to see the client 49 00:04:38,720 --> 00:04:41,030 PC only sees. 50 00:04:42,360 --> 00:04:45,360 The RFC 1918 addresses. 51 00:04:45,840 --> 00:04:53,310 It doesn't see Network eight and these routers on the Internet use Network eight. 52 00:04:55,890 --> 00:05:02,940 So if I go back to say this writer here and look at the packet notice. 53 00:05:05,020 --> 00:05:07,870 Inbound Purdue and outbound Purdue. 54 00:05:07,900 --> 00:05:11,050 Both are using public IP addresses. 55 00:05:11,730 --> 00:05:17,580 But if I go back again to this router, this is where the encapsulation is taking place. 56 00:05:19,380 --> 00:05:19,890 Inbound. 57 00:05:19,890 --> 00:05:24,420 Purdue contains or have seen 1918 addresses outbound. 58 00:05:24,420 --> 00:05:26,640 Purdue has public IP addresses. 59 00:05:28,090 --> 00:05:32,710 A cheery header and the original encapsulated packet. 60 00:05:35,010 --> 00:05:36,750 When we go forward. 61 00:05:38,790 --> 00:05:39,810 To hear. 62 00:05:40,890 --> 00:05:42,780 Packet is DX encapsulated. 63 00:05:43,200 --> 00:05:54,300 So inbound we have IP header duri IP header, but outbound we don't see the public IP addresses. 64 00:05:54,510 --> 00:05:59,670 We don't see the geo headers that's been stripped. 65 00:06:00,430 --> 00:06:02,200 So headers are added here. 66 00:06:02,230 --> 00:06:04,120 Headers are removed here. 67 00:06:04,420 --> 00:06:06,370 So how did you get on? 68 00:06:06,430 --> 00:06:08,710 Were you able to complete the lab? 69 00:06:09,070 --> 00:06:12,310 Did you get your grid tunnel up and running?