1 00:00:00,710 --> 00:00:06,350 So let's look at the basic concepts of networking and, of course, the mother of all networks, the 2 00:00:06,350 --> 00:00:06,740 Internet. 3 00:00:07,980 --> 00:00:14,730 The Internet is a global system of interconnected computer networks that use the standard Internet protocol 4 00:00:14,730 --> 00:00:23,290 suite, often called TCP IP, although not all applications used TCP to serve billions of users worldwide. 5 00:00:23,940 --> 00:00:31,740 It's a network of networks that consist of millions of private, public, academic, business and government 6 00:00:31,740 --> 00:00:34,170 networks of local to global scope. 7 00:00:35,080 --> 00:00:41,470 That are linked by a broad array of electronic wireless and optical networking technologies. 8 00:00:42,360 --> 00:00:48,780 The Internet carries an extensive range of information, resources and services such as the interlinked 9 00:00:48,780 --> 00:00:55,140 hypertext documents of the World Wide Web W-W and the infrastructure to support e-mail. 10 00:00:57,240 --> 00:01:02,940 The origins of the Internet reach back to research done in the 1960s, commissioned by the United States 11 00:01:02,940 --> 00:01:09,240 government in collaboration with private and commercial interests to build robust, fault tolerant and 12 00:01:09,240 --> 00:01:10,980 distributed computer networks. 13 00:01:12,090 --> 00:01:19,860 The primary precursor network, the ARPANET, initially served as a backbone for interconnection of 14 00:01:19,860 --> 00:01:23,220 regional, academic and military networks in the 1980s. 15 00:01:24,350 --> 00:01:30,260 The funding of a new U.S. backbone by the National Science Foundation in the 1980s, as well as private 16 00:01:30,260 --> 00:01:37,070 funding for other commercial backbones, led to worldwide participation in the development of new networking 17 00:01:37,070 --> 00:01:40,490 technologies and the merger of many networks. 18 00:01:42,900 --> 00:01:50,160 The commercialization of what was by the 1990s, an international network resulted in its popularisation 19 00:01:50,310 --> 00:01:56,700 and incorporation into virtually, I'd say, every aspect of modern human life. 20 00:01:58,000 --> 00:02:05,740 So as of 31st December 2017, more than four point one billion people, nearly 55 percent of the whole 21 00:02:05,740 --> 00:02:08,380 world population use the services of the Internet. 22 00:02:09,220 --> 00:02:11,740 Now, put that in a little perspective here. 23 00:02:11,770 --> 00:02:19,150 That's 95 percent of North Americans and that 85 percent of Europeans are Internet users. 24 00:02:21,230 --> 00:02:25,160 Now, before we're talking about the Internet protocol or what we call IP. 25 00:02:26,190 --> 00:02:29,340 We should know what a protocol actually is. 26 00:02:30,710 --> 00:02:36,770 A protocol is simply a set of rules governing how things work in a certain technology. 27 00:02:37,990 --> 00:02:40,180 So that there is some kind of standardization. 28 00:02:41,680 --> 00:02:49,090 Protocols are also typically in charge of sending the right data to the right PC, making sure the data 29 00:02:49,090 --> 00:02:53,830 gets to the right program, as well as organizing the data to be sent. 30 00:02:55,340 --> 00:03:02,540 Protocols are to computers, what languages to humans, for instance, this course is in English, to 31 00:03:02,540 --> 00:03:04,910 understand it, you must be able to understand English. 32 00:03:05,450 --> 00:03:12,290 So similarly, for two devices on a network to successfully communicate, they must both understand 33 00:03:12,290 --> 00:03:13,520 the same protocols. 34 00:03:14,490 --> 00:03:20,670 So I know we're going to talk about this in detail later, but we'll talk a little bit now about IP 35 00:03:20,670 --> 00:03:22,320 to better understand the Internet. 36 00:03:23,420 --> 00:03:29,090 Internet Protocol IP describes how data packets move through network. 37 00:03:30,020 --> 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 38 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 39 00:03:42,710 --> 00:03:43,910 whole framework. 40 00:03:45,180 --> 00:03:53,040 The IP protocol standardizes the way machines over the Internet or any IP network forward or root their 41 00:03:53,040 --> 00:03:55,710 packets based on their IP addresses. 42 00:03:57,060 --> 00:04:02,850 So along with addressing routing is one of the main functions of the IP protocol. 43 00:04:03,980 --> 00:04:10,700 Routing consists of forwarding IP packets from source to destination machines over network based on 44 00:04:10,700 --> 00:04:11,750 their IP addresses. 45 00:04:12,720 --> 00:04:19,830 An IP address is a unique address, identifying a machine which can be a computer, a server, an electronic 46 00:04:19,830 --> 00:04:27,690 device, a router, a phone, you name it, on a network, thus serving, routing and forwarding IP 47 00:04:27,690 --> 00:04:30,270 packets from source to destination. 48 00:04:32,060 --> 00:04:37,520 Basically, every computer connected to the Internet is given an IP address by the Internet service 49 00:04:37,520 --> 00:04:42,830 provider and the computer becomes accessible to others via this IP address. 50 00:04:44,280 --> 00:04:47,390 So let's see what the Internet looks like on its most basic level. 51 00:04:48,900 --> 00:04:56,130 Here we have a home network with a router given by the Internet service provider, or ISP, remember 52 00:04:56,130 --> 00:05:01,860 that modem that's given to you by your ISP and the devices it connects to the Internet? 53 00:05:03,100 --> 00:05:08,310 This is a corporation with a lot of end user computers and servers as well. 54 00:05:09,510 --> 00:05:14,370 There's a public body here, again, with a lot of servers and a lot of End-user computers. 55 00:05:15,230 --> 00:05:21,800 Here is a hosting company with a Web server farm hosting to their customers. 56 00:05:22,160 --> 00:05:28,020 Now here's a cloud provider such as Amazon Web Services hosting a lot of servers again. 57 00:05:28,550 --> 00:05:30,020 And here there's another home. 58 00:05:30,940 --> 00:05:36,430 And they're all connected to each other over telecom company routers.