The Big Picture

The Internet is a network of independent computers and 0:00 other hardware devices connected together. 0:03 You can think of this as a bunch of wires that let computers around the world 0:06 communicate with each other. 0:10 Connected to these wires are forests of other devices, 0:12 which make the Internet work like servers, routers, and switches. 0:14 The primary network in core routers around the world make up the backbone of 0:19 the Internet, and support the exchange of Internet traffic between countries, 0:23 continents, and across oceans. 0:27 Because of the diversity in hardware used all over the Internet, 0:30 everyone needs to work cooperatively. 0:34 The developers behind the software used on the Internet agreed to follow 0:36 a set of rules called protocols, when sending and receiving information. 0:40 Let's look at what's involved when you go to the homepage of your favorite website. 0:46 For the purposes of this example, 0:50 let's say your wirelessly connected to the Internet at your house. 0:52 After opening up a web browser and typing in a URL, your browser uses a special 0:56 protocol called HTTP or Hyper Text Transfer Protocol. 1:01 This is a set of rules for asking for and getting webpages. 1:07 But there's an even more basic set of protocols under this, called TCP/IP. 1:11 Which is short for Transmission Control Protocol and Internet Protocol. 1:16 These are the rules for sending and 1:21 receiving any data whether it's email, webpages or files on the Internet. 1:22 Once you initial your request TCP IP protocols take your request, 1:28 webpages, videos, or emails and break them into little packets of data and 1:33 send them in the fastest way possible. 1:38 From client to server and back again. 1:41 The TCP IP protocols are a fundamental part of the internet 1:43 which we'll learn more about later in another video. 1:47 After you request a web page TCP IP send your request wirelessly over 1:50 radio waves either to a router or directly to a wireless modem. 1:54 If you have a router what was a wireless request 1:58 is now sent along an ethernet chord to your modem. 2:02 Your modem then sends the packets along a coaxial cable or 2:05 phone line to the outside of your house where your internet service provider or 2:08 ISP connects you to the Internet. 2:12 The main network made of fiber optic cables and computers. 2:14 Once it reaches this point your request is now sent from one server to another 2:19 until it reaches the server that's hosting the website you wanted. 2:23 Then, the webpage you requested is returned in just the same way. 2:28 If this all happens correctly, the packets of data arrive, are reassembled, and 2:32 the web browser shows you a perfect copy of the webpage. 2:37 Usually this happens very quickly. 2:41 Often in just a matter of seconds. 2:43 So the internet has one job, letting computers and 2:46 other devices around the world to talk to each other. 2:49 But accomplishing that job is no easy task. 2:52 In the next few videos, let's look at each aspect of the internet in more detail. 2:55