1 00:00:00,740 --> 00:00:06,320 ‫So let's look at the basic concepts of networking and, of course, the mother of all networks, the 2 00:00:06,320 --> 00:00:06,700 ‫internet. 3 00:00:08,010 --> 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 --> 00:00:23,280 ‫suite, often called TCP IP, although not all applications use TCP to serve billions of users worldwide. 5 00:00:23,970 --> 00:00:31,710 ‫It's a network of networks that consist of millions of private public, academic, business and government 6 00:00:31,710 --> 00:00:34,140 ‫networks of local to global scope. 7 00:00:35,090 --> 00:00:41,420 ‫That are linked by a broad array of electronic wireless and optical networking technologies. 8 00:00:42,360 --> 00:00:48,750 ‫The internet carries an extensive range of information, resources and services, such as the interlinked 9 00:00:48,750 --> 00:00:55,110 ‫hypertext documents of the World Wide Web, W WW and the infrastructure to support email. 10 00:00:57,240 --> 00:01:01,170 ‫The origins of the internet reach back to research done in the 1960s. 11 00:01:01,620 --> 00:01:06,540 ‫Commissioned by the United States government in collaboration with private and commercial interests 12 00:01:06,810 --> 00:01:10,950 ‫to build robust, fault tolerant and 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 --> 00:01:23,190 ‫regional, academic and military networks in the 1980s. 15 00:01:24,380 --> 00:01:30,230 ‫The funding of a new U.S. backbone by the National Science Foundation in the 1980s, as well as private 16 00:01:30,230 --> 00:01:37,040 ‫funding for other commercial backbones, led to worldwide participation in the development of new networking 17 00:01:37,070 --> 00:01:40,430 ‫technologies and the merger of many networks. 18 00:01:42,900 --> 00:01:50,130 ‫The commercialization of what was by the 1990s and international network resulted in its popularization 19 00:01:50,310 --> 00:01:56,670 ‫and incorporation into virtually, I'd say, every aspect of modern human life. 20 00:01:58,030 --> 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 00:02:09,250 --> 00:02:11,690 ‫Now I'll put that in a little perspective here. 23 00:02:11,770 --> 00:02:19,120 ‫It's 95 percent of North Americans and about 85 percent of Europeans are internet users. 24 00:02:21,240 --> 00:02:25,140 ‫Now, before talking about the internet protocol or what we call IP. 25 00:02:26,170 --> 00:02:29,320 ‫We should know what a protocol actually is. 26 00:02:30,770 --> 00:02:36,740 ‫A protocol is simply a set of rules governing how things work in a certain technology. 27 00:02:38,020 --> 00:02:40,180 ‫So that there is some kind of standardization. 28 00:02:41,650 --> 00:02:49,060 ‫Protocols are also typically in charge of sending the right data to the right PC, making sure the data 29 00:02:49,060 --> 00:02:53,800 ‫gets to the right program, as well as organizing the data to be sent. 30 00:02:55,340 --> 00:02:58,910 ‫Protocols are to computers, what languages to humans? 31 00:02:59,660 --> 00:03:01,730 ‫For instance, this course is in English. 32 00:03:02,390 --> 00:03:04,930 ‫To understand it, you must be able to understand English. 33 00:03:05,510 --> 00:03:12,290 ‫So similarly, for two devices on a network to successfully communicate, they must both understand 34 00:03:12,290 --> 00:03:13,520 ‫the same protocols. 35 00:03:14,520 --> 00:03:20,640 ‫So I know we're going to talk about this in detail later, but we'll talk a little bit now about IP 36 00:03:20,670 --> 00:03:22,260 ‫to better understand the internet. 37 00:03:23,490 --> 00:03:29,160 ‫Internet protocol IP describes how data packets move through a network. 38 00:03:30,090 --> 00:03:36,450 ‫So when you have a protocol, you are sure that all machines on a network or in the world when it comes 39 00:03:36,450 --> 00:03:39,160 ‫to the internet, however different they might be. 40 00:03:39,180 --> 00:03:43,950 ‫Speak the same language and can integrate into the whole framework. 41 00:03:45,250 --> 00:03:53,080 ‫The IP protocol standardizes the way machines over the internet or any IP network forward or route their 42 00:03:53,080 --> 00:04:00,910 ‫packet based on their IP addresses, so along with addressing, routing is one of the main functions 43 00:04:00,910 --> 00:04:01,930 ‫of the IP protocol. 44 00:04:03,070 --> 00:04:09,790 ‫Routing consists of forwarding IP packets from source to destination machines over network based on 45 00:04:09,790 --> 00:04:10,810 ‫their IP addresses. 46 00:04:11,820 --> 00:04:18,900 ‫An IP address is a unique address, identifying a machine which can be a computer server, an electronic 47 00:04:18,900 --> 00:04:27,270 ‫device, a router, a phone, you name it on a network, thus serving, routing and forwarding IP packets 48 00:04:27,510 --> 00:04:29,340 ‫from source to destination. 49 00:04:31,160 --> 00:04:36,620 ‫Basically, every computer connected to the internet is given an IP address by the internet service 50 00:04:36,620 --> 00:04:41,900 ‫provider, and the computer becomes accessible to others via this IP address. 51 00:04:43,400 --> 00:04:46,480 ‫So let's see what the internet looks like on its most basic level. 52 00:04:48,030 --> 00:04:54,120 ‫Here we have a home network with a router given by the internet service provider or ISP. 53 00:04:54,750 --> 00:05:00,930 ‫Remember that modem that's given to you by your ISP and the devices it connects to the internet? 54 00:05:02,190 --> 00:05:07,410 ‫This is a corporation with a lot of end user computers and servers as well. 55 00:05:08,630 --> 00:05:13,430 ‫There's a public body here again with a lot of servers and a lot of end user computers. 56 00:05:14,330 --> 00:05:20,870 ‫Here is a hosting company with a Web server farm hosting to their customers. 57 00:05:21,290 --> 00:05:27,080 ‫Now here's a cloud providers such as Amazon Web Services hosting a lot of servers again. 58 00:05:27,680 --> 00:05:29,090 ‫And here there's another home. 59 00:05:30,040 --> 00:05:35,470 ‫And they're all connected to each other over telecom company routers.