1 00:00:00,510 --> 00:00:06,870 So let's look at the basic concepts of networking and of course, the mother of all networks, the Internet. 2 00:00:07,810 --> 00:00:14,650 The Internet is a global system of interconnected computer networks that use the standard Internet protocol 3 00:00:14,650 --> 00:00:16,990 suite, often called TCP IP. 4 00:00:17,260 --> 00:00:23,530 Although not all applications use TCP to serve billions of users worldwide. 5 00:00:23,680 --> 00:00:31,630 It's a network of networks that consists of millions of private, public, academic, business and government 6 00:00:31,660 --> 00:00:34,330 networks of local to global scope. 7 00:00:34,880 --> 00:00:41,600 That are linked by a broad array of electronic, wireless and optical networking technologies. 8 00:00:42,120 --> 00:00:48,660 The Internet carries an extensive range of information, resources and services such as the inter-linked 9 00:00:48,690 --> 00:00:55,140 hypertext documents of the World Wide Web and the infrastructure to support email. 10 00:00:57,040 --> 00:01:02,860 The origins of the Internet reach back to research done in the 1960s, commissioned by the United States 11 00:01:02,860 --> 00:01:08,830 government in collaboration with private and commercial interests to build robust, fault, tolerant 12 00:01:08,830 --> 00:01:11,110 and distributed computer networks. 13 00:01:11,970 --> 00:01:14,100 The primary precursor network. 14 00:01:14,130 --> 00:01:22,200 The Arpanet initially served as a backbone for interconnection of regional, academic and military networks 15 00:01:22,200 --> 00:01:23,370 in the 1980s. 16 00:01:24,140 --> 00:01:30,170 The funding of a new US backbone by the National Science Foundation in the 1980s, as well as private 17 00:01:30,170 --> 00:01:36,980 funding for other commercial backbones, led to worldwide participation in the development of new networking 18 00:01:37,010 --> 00:01:40,640 technologies and the merger of many networks. 19 00:01:42,720 --> 00:01:50,160 The commercialization of what was by the 1990s and international network resulted in its popularization 20 00:01:50,160 --> 00:01:56,790 and incorporation into virtually, I'd say, every aspect of modern human life. 21 00:01:57,760 --> 00:02:06,790 So as of 31st December 2017, more than 4.1 billion people, nearly 55% of the whole world population, 22 00:02:06,790 --> 00:02:08,560 used the services of the Internet. 23 00:02:08,949 --> 00:02:11,650 Now, put that in a little perspective here. 24 00:02:11,650 --> 00:02:19,270 That's 95% of North Americans and about 85% of Europeans are Internet users. 25 00:02:21,060 --> 00:02:24,990 Now, before talking about the Internet protocol or what we call IP. 26 00:02:25,980 --> 00:02:29,490 We should know what a protocol actually is. 27 00:02:30,620 --> 00:02:36,890 A protocol is simply a set of rules governing how things work in a certain technology. 28 00:02:37,780 --> 00:02:40,330 So that there is some kind of standardization. 29 00:02:41,400 --> 00:02:48,990 Protocols are also typically in charge of sending the right data to the right PC, making sure the data 30 00:02:49,020 --> 00:02:53,970 gets to the right program, as well as organizing the data to be sent. 31 00:02:55,120 --> 00:02:56,890 Protocols are to computers. 32 00:02:56,890 --> 00:02:59,170 What language is to humans? 33 00:02:59,350 --> 00:03:01,960 For instance, this course is in English. 34 00:03:02,140 --> 00:03:05,140 To understand it, you must be able to understand English. 35 00:03:05,170 --> 00:03:10,240 So similarly, for two devices on a network to successfully communicate. 36 00:03:10,270 --> 00:03:13,690 They must both understand the same protocols. 37 00:03:14,270 --> 00:03:20,300 So I know we're going to talk about this in detail later, but we'll talk a little bit now about IP. 38 00:03:20,480 --> 00:03:22,430 To better understand the Internet. 39 00:03:23,300 --> 00:03:24,680 Internet protocol. 40 00:03:24,710 --> 00:03:29,330 IP describes how data packets move through a network. 41 00:03:29,870 --> 00:03:36,380 So when you have a protocol, you are sure that all machines on a network or in the world when it comes 42 00:03:36,380 --> 00:03:42,710 to the internet, however different they might be, speak the same language and can integrate into the 43 00:03:42,710 --> 00:03:44,090 whole framework. 44 00:03:45,010 --> 00:03:53,050 The IP protocol standardizes the way machines over the internet or any IP network forward or route their 45 00:03:53,050 --> 00:03:55,920 packets based on their IP addresses. 46 00:03:55,930 --> 00:04:02,080 So along with addressing routing is one of the main functions of the IP protocol. 47 00:04:02,890 --> 00:04:09,700 Routing consists of forwarding IP packets from source to destination machines over network based on 48 00:04:09,700 --> 00:04:10,990 their IP addresses. 49 00:04:11,600 --> 00:04:18,829 An IP address is a unique address identifying a machine which can be a computer, a server, an electronic 50 00:04:18,829 --> 00:04:22,670 device, a router, a phone, you name it, on a network. 51 00:04:22,700 --> 00:04:29,480 Thus serving routing and forwarding IP packets from source to destination. 52 00:04:30,970 --> 00:04:36,520 Basically, every computer connected to the Internet is given an IP address by the Internet service 53 00:04:36,520 --> 00:04:42,070 provider, and the computer becomes accessible to others via this IP address. 54 00:04:43,120 --> 00:04:46,630 So let's see what the Internet looks like on its most basic level. 55 00:04:47,810 --> 00:04:54,290 Here we have a home network with a router given by the Internet service provider or ISP. 56 00:04:54,530 --> 00:04:59,900 Remember that modem that's given to you by your ISP and the devices? 57 00:04:59,900 --> 00:05:01,070 It connects to the Internet. 58 00:05:01,940 --> 00:05:07,580 This is a corporation with a lot of end user computers and servers as well. 59 00:05:08,410 --> 00:05:13,570 There's a public body here, again, with a lot of servers and a lot of end user computers. 60 00:05:14,140 --> 00:05:21,010 Here is a hosting company with a web server farm hosting to their customers. 61 00:05:21,040 --> 00:05:27,380 Now here's a cloud provider such as Amazon Web Services hosting a lot of servers again. 62 00:05:27,400 --> 00:05:29,260 And here there's another home. 63 00:05:29,880 --> 00:05:35,670 And they're all connected to each other over telecom company routers.