1 00:00:00,990 --> 00:00:05,160 The CPI is a combination of two protocols. 2 00:00:05,460 --> 00:00:13,050 These are the actual in my screen, just these are the transmission protocol, transmission control 3 00:00:13,050 --> 00:00:15,450 protocol plus internet protocol. 4 00:00:16,500 --> 00:00:17,070 So. 5 00:00:18,620 --> 00:00:23,680 These two particles form part of the Internet protocol suite IPS. 6 00:00:24,080 --> 00:00:31,220 So a conceptual model of how Nature Protocol sent network traffic over the internet that breaks down 7 00:00:31,220 --> 00:00:37,850 network communication into four layers, as shown in this illustration. 8 00:00:38,540 --> 00:00:43,820 So as you can see, Internet Protocol Application Layer transports their internet layer link layer, 9 00:00:43,820 --> 00:00:47,690 and these are the what these layers use, what protocols, says Laotians. 10 00:00:47,960 --> 00:00:50,540 And this is the link layer is the physical layer. 11 00:00:51,110 --> 00:00:57,470 So, uh, these are the two four layers from a protocol stack. 12 00:00:58,160 --> 00:01:03,410 So these links here's the all clear, uh, link layer. 13 00:01:03,800 --> 00:01:07,250 This is the layer one, layer two, layer three and layer form. 14 00:01:07,580 --> 00:01:09,770 This start with a link, clearly and one. 15 00:01:10,160 --> 00:01:12,500 So this layer is the lowest level. 16 00:01:12,500 --> 00:01:19,880 And this, uh, describes the physical mechanisms used, uh, to transfer information between nodes 17 00:01:20,060 --> 00:01:21,980 on a local network. 18 00:01:22,830 --> 00:01:23,570 Uh, Ben. 19 00:01:23,610 --> 00:01:27,340 One examples include, uh, internet here. 20 00:01:27,350 --> 00:01:28,270 Can I show you? 21 00:01:28,310 --> 00:01:31,100 So this is the Ethernet port, for example. 22 00:01:31,580 --> 00:01:36,260 Um, or point to point, uh, protocol. 23 00:01:36,780 --> 00:01:40,510 Uh, so these are the physical layer and top of them. 24 00:01:40,520 --> 00:01:43,490 This is the layer number two layer number two. 25 00:01:44,360 --> 00:01:46,570 Uh, so this is the internet layer. 26 00:01:46,580 --> 00:01:50,960 So this layer provides the mechanisms for addressing network notes. 27 00:01:51,320 --> 00:01:52,550 Well, I can layer one. 28 00:01:52,940 --> 00:01:56,390 The nodes don't have to be located on the local network. 29 00:01:56,600 --> 00:02:02,900 This level contains the, uh, IP for IPv6 on a model networks. 30 00:02:02,900 --> 00:02:08,450 The actual protocol used called either B I IP version four or IP version six. 31 00:02:08,900 --> 00:02:15,050 And and then let's talk about our, uh, third layer transport layer. 32 00:02:15,290 --> 00:02:15,590 Yeah. 33 00:02:16,610 --> 00:02:25,010 Transport layer these layers is responsible for connection between clients and servers, so sometimes 34 00:02:25,010 --> 00:02:31,910 ensuring the correct order of Pekar's and providing service multiplexing service multiplexing allows 35 00:02:31,910 --> 00:02:39,050 a single node to support multiple different services by assigning a different number for each service. 36 00:02:39,410 --> 00:02:43,090 So this number is called a part TCP. 37 00:02:43,220 --> 00:02:46,670 The user data protocol operate on this layer. 38 00:02:46,670 --> 00:02:51,830 TCP and UDP operate in this transport layer. 39 00:02:52,550 --> 00:03:00,730 And lastly, we have application layer here, so this layer contains network protocols such as Hypertext, 40 00:03:00,930 --> 00:03:08,210 the hypertext transfer protocol ATP, which transfers web page contents. 41 00:03:08,630 --> 00:03:16,850 Uh, we have the simple mail transport protocol for which transferring which transferring email and 42 00:03:16,850 --> 00:03:22,250 domain name system protocol, which converts a name to and not on the network. 43 00:03:22,800 --> 00:03:28,910 Further, this course we will focus primarily on this layer, actually, but we will focus on all of 44 00:03:28,910 --> 00:03:29,330 this there. 45 00:03:29,330 --> 00:03:31,220 So this is the most important layer for us. 46 00:03:31,970 --> 00:03:38,780 Each layer interacts only with the layer of two and below, but there is a must be external interaction 47 00:03:38,780 --> 00:03:39,620 within the stack. 48 00:03:40,190 --> 00:03:42,440 So like that. 49 00:03:48,310 --> 00:03:48,700 One. 50 00:03:49,270 --> 00:03:49,660 Yes. 51 00:04:08,150 --> 00:04:08,550 There. 52 00:04:13,900 --> 00:04:14,370 So. 53 00:04:19,690 --> 00:04:22,440 Now, let's pretend that new figure. 54 00:04:23,230 --> 00:04:25,060 Uh, for better understanding. 55 00:04:26,380 --> 00:04:26,800 Um. 56 00:04:27,890 --> 00:04:28,430 Yes. 57 00:04:29,270 --> 00:04:31,580 This is the one box here. 58 00:04:32,030 --> 00:04:33,960 And this is the mail. 59 00:04:34,700 --> 00:04:36,740 This will be our mail application. 60 00:04:41,640 --> 00:04:42,900 Mail application. 61 00:04:48,380 --> 00:04:49,220 Vacation. 62 00:04:52,930 --> 00:04:54,290 This is the mail application. 63 00:04:54,580 --> 00:05:00,160 And, um, this is the human years, so it's. 64 00:05:01,780 --> 00:05:04,270 Justin, users here, for example. 65 00:05:06,570 --> 00:05:09,420 This will be our user, so. 66 00:05:12,920 --> 00:05:16,370 It's it's some books here as well. 67 00:05:16,730 --> 00:05:28,010 So this will be a user interface interface, which is harsh HTML hash, HTML rendering, and we have 68 00:05:28,340 --> 00:05:30,740 we will conduct ourselves here. 69 00:05:32,030 --> 00:05:39,500 Content partners like, uh, tech such will jpg content. 70 00:05:41,230 --> 00:05:42,130 Serves. 71 00:05:43,300 --> 00:05:44,320 Passers. 72 00:05:45,670 --> 00:05:55,090 What this feeling is text, for example, hushed html jpg, the on the wheel, uh, top of below them 73 00:05:55,240 --> 00:05:56,350 is very real. 74 00:05:56,350 --> 00:05:59,710 Have network communication network home. 75 00:06:02,210 --> 00:06:11,150 So what these will is and SMTP is SMTP, for example, pop three or three and IMAP. 76 00:06:11,240 --> 00:06:12,770 So this is the email application. 77 00:06:13,640 --> 00:06:22,580 Uh, so SMTP, POP3 and IMAP is the mail protocols, and this will be network network. 78 00:06:23,600 --> 00:06:24,050 Here. 79 00:06:25,630 --> 00:06:27,880 And servers here, server. 80 00:06:29,950 --> 00:06:30,490 Sir. 81 00:06:32,560 --> 00:06:36,220 This network report is directly the server and user interface. 82 00:06:36,700 --> 00:06:38,890 Will direct that it'll go to our homeland. 83 00:06:39,430 --> 00:06:42,910 So typically, applications contains these components. 84 00:06:43,330 --> 00:06:47,140 First is network communication. 85 00:06:48,130 --> 00:06:56,000 So this component communicates over the network and processes incoming and outgoing outgoing data. 86 00:06:56,330 --> 00:06:57,450 What email application? 87 00:06:57,460 --> 00:07:04,960 The network communication is most likely in the standard protocol, such as a SMTP pump three and IMAP, 88 00:07:05,650 --> 00:07:08,200 and we have here content partners as well. 89 00:07:08,380 --> 00:07:09,850 So data is transferred over. 90 00:07:09,850 --> 00:07:15,350 A network usually contains content that must be extracted and processed. 91 00:07:15,910 --> 00:07:24,250 Content might be include textual data such as the body of an e-mail or it might be contain pictures 92 00:07:24,370 --> 00:07:25,240 or videos. 93 00:07:26,320 --> 00:07:28,930 And we have user interface for user. 94 00:07:29,500 --> 00:07:37,870 So the user interface allows the user to be received emails and to create new emails for transmission 95 00:07:38,080 --> 00:07:39,220 in a mail application. 96 00:07:39,220 --> 00:07:47,650 The user interface might display emails using hashed email or be in a web of a browser. 97 00:07:48,730 --> 00:07:52,810 Not that the user interacting with the user interface doesn't have to be human. 98 00:07:52,810 --> 00:08:00,400 Being caused by the application that automates the sending and receiving of emails triggered a command 99 00:08:00,400 --> 00:08:01,030 line tool. 100 00:08:02,090 --> 00:08:10,190 And we have here data encapsulation, which we will discuss this in the next lecture.