the internet - super highway

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TK – 8 technology course materials that weave together: terminology how things work tools inventors history trends

The InternetAn Information Super Highway

Grade 5 - 8

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Copyright © 2007 TechnoTeachers. All rights reserved.

Overview

Author: Evelyn ChalekiDate: October 30, 2007Contact: [email protected]

Copyright © 2007 TechnoTeachers. All rights reserved.Educators may use these materials for classroom and instructional use only and not for resale or redistribution. The Content may not be published, broadcast or reproduced without the prior written permission of TechnoTeachers.

The images are from www.clipart.com or public domain unless otherwise specified.

mailto:[email protected]

http://www.clipart.com/

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Overview

‘The Internet – An Information Super Highway’ introduces students to the basic concepts of how the Internet works by using terminology that they understand – using highways as an analogy. It describes the different components that make up the Internet - hardware, software, and servers.

Why is this important?Students use the Internet daily. It is helpful for them to understand how it works.

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How does it work?

When you want to access information on the Internet from your PC…– You start up an Internet Browser application like Microsoft Internet

Explorer, Netscape Navigator, or Opera, etc.– You put in a URL such as: www.google.com– You go to the Google website

It seems simple, but what is really going on behind the scenes? The actual Internet is made up of hardware, software, and servers. Let’s take a look….

http://www.google.com/

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Network Hardware

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Network Hardware

Hardware is the physical connections - the things you can see and touch. In order for you to communicate or exchange information with Google, there has to be a connection from your computer all the way to the Google computer at the other end. This is done using:

– Modems– Cable Modems– DSL Modems– Hubs– Routers– Repeaters– Bridges– Gateways– PC access (Ethernet card, WIFI, wireless

cable, wireless DSL, etc.)– And the physical network that connects these

devices (wiring, cables, T1 lines, satellite, etc.)

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Network Hardware

You can think of the Internet like a super highway. Let’s say your computer is like your house and the Google server is like Google Headquarters in Mountain View, California. The Internet hardware is just like your driveway, roads, and highway that would allow you to drive to Google Headquarters.

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Network Hardware @ Home

Let’s take a simple case. Your house has a single computer that is connect to the Internet using a service from your cable company.

– Your computer has a network card.– That card is connected to a cable modem/router.– The cable modem/router is connected to the wall outlet provided by the cable company which is

connected to the Internet (run by your cable company who is your Internet Service Provider)

To the computer

To the wall outlet (and out to the Internet)

Cable Modem/Router

http://upload.wikimedia.org/wikipedia/commons/b/bd/EtherLinkIII_ubt.jpg

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Network Hardware @ School

Unlike the previous example, in your school there are many computers that need to access the Internet at the same time. These computers share a local network that is internal to your school called a Local Area Network (LAN). This LAN is then connected to the Internet to provide access to all the computers on the LAN.

– Each computer has a network card.– Each computer is connected to the LAN by connecting the network card to a hub.– The hub is connected to a router which is connected to the Internet (run by the school’s Internet service provider).

To the Hub

Out to the InternetLocal Area

Network (LAN)

Cable Modem/Router

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Network Hardware – The Internet

The network that connects you to the information you are looking for is a network of networks and is not owned by any one company. Just like highways, networks are shared resources and there are lots of different ways to get from point A to point B.

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Network Hardware @ Google Headquarters

Google has a network of servers that enables you to use their search engines which are connected to the Internet. Based on Wikipedia, some people estimate that Google maintains over 450,000 servers distributed globally.

Out to the Internet

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Network Hardware - Wireless

Up until now, we’ve said you have to have a physical connection that connects your PC all the way to Google Headquarters just like the roads, but what about wireless connections like wireless routers, cellular, Bluetooth, WiFi, WiMax, and satellite? Isn’t that like not having a road? Well, when there are no roads, then you need to fly. You need to take the roads to an airport, fly to another airport, and then get back on the road to your destination. The airports would be the wireless devices that let you fly between them.

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Network Software

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Network Software

If the roads are the hardware, then the software is what directs traffic. When you communicate or exchange information with another site, the software tells you the quickest or shortest route to your destination, determines priority, and manages security. The software runs on the hardware. The software does other things as well, but we’re going to just focus on these aspects for now.

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Network Software – Which route?

The network software directs which path you take. Each hardware device you run into will direct you to the next one.

In the example of getting to Google Headquarters, it would be like running into a police officer directing traffic at every intersection on your way there.

• When you get to the end of your driveway, there’s a police officer that asks you “where are you going?” You say “Google HQ, Mountain View, CA”. The officer says “The fastest way is to take Broad St. (the road you live on) to Main Street”.

• When you get to the corner of Broad and Main St. an officer there asks you “where are you going?” You say “Google HQ, Mountain View, CA”. The officer says “The fast way is to take this road (Main Street) to Route 66”.

• At the intersection of Main Street and Route 66 you meet an officer who asks you “where are you going?” You say “Google HQ Mountain View, CA”. He says “there’s an accident on Route 66. Stay on Main Street and take Route 95 until you get to….”

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Network Software – Priority

Not all information traveling on the Internet has the same priority. Some things will get to go before other things. For example, a telephone call over the Internet (VoIP) will have priority over email because the telephone conversation is in real-time and needs a higher priority in order to sound good.

Using our analogy, if while on your way to Google HQ, an ambulance comes along with it’s siren blaring, you need to pull over and let the ambulance go first.

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Network Software – Security

The network software also manages security – who gets access to what.

Using our analogy, if your driving through Washington, DC and you try and drive up to the White House, a security guard will only allow you to enter if you can prove that you are supposed to be there.

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Network Software - Protocols

• Because multiple computers and devices share a network, the network protocol tells everyone how to behave. A common Internet network protocol is TCP/IP.

• It’s similar to the rules of the road which enable multiple cars to share the roads safely. That’s why there are speed limits, how to change lanes, right turn on red, merging from on and off ramps, traffic lights, stop signs, 4 way stops, etc.

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Network Software – Packet Network

The Internet is a packet network. That means whatever is sent across it is broken down into little pieces called packets. Each piece is sent separately and might take different routes to the destination where it is put together again.

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Network Software - Packet Network

Continuing with our highway analogy. Let’s say the information you are sending over the Internet is like a shipment of furniture.

Let’s say you live in Virginia and want to give your bedroom furniture to your younger cousin who lives in New York. You have a bed frame, mattress, dresser, and end table.

– Your dad drives one truck with the bed frame and the dresser drawers and takes Route 95

– Your uncle drives a truck with the mattress, dresser and end table and takes Route 81

Each truck is like a packet. They both leave from your house and arrive at your cousin’s. It doesn’t matter which car gets there first. Once they get there, the furniture gets reassembled in her room.

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Servers

The Internet has many different types of servers. We will only talk about two in this module.

– Domain Name System (DNS) Server– Email Server

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DNS Servers – TCP/IP Addresses

A TCP/IP Address is like a street address. It is the address computers and the network software uses and tells them how to get a hold of your computer.

– Your computer can either be assigned a permanent TCP/IP address (static)– Or you can get a temporary one (dynamic) from a pool of addresses when you get

on the network (e.g. ISPs have a pool of tcp/ip addresses)

128.129.204.21091 Broad StreetRichmond, VA

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DNS Servers – URLs

http://www.google.com

Hypertext Transport Protocol (http), the message format computers use to exchange

information on the Internet.

www stands for World Wide Web

The code following the period (.com) is called the generic

top-level domain. This domain indicates the type of organization they represent.

www.google.com is the domain name. google.com is the registered domain

name. The IP address and the server name are interchangeable.

A URL (Uniform Resource Locator) is an Internet web address like www.google.com that connects your computer to an image, file, page or program on the Internet. It’s easier to remember than a TCP/IP address.

http://www.google.com/

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DNS Servers

There are a series of servers on the network, called Domain Name System servers, that translate URLs to TCP/IP addresses. This all happens behind the scenes and you don’t need to do anything.

www.google.com

123.235.20.7

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Email Servers

Electronic Mail or email works like regular mail (snail mail). First you have to provide a destination address and return address.

[email protected]

[email protected]

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Email Servers

When you mail your letter, it first goes to your post office to be sorted. If the letter is for someone else that uses the same post office, it is delivered to them.

Your email first goes to your mail server. If the email is for someone else that shares the same mail server, it is delivered automatically to their mailbox.

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Email Servers

If the letter is for someone who uses a different post office, then it is sent to the proper post office and delivered.

If the email is for someone who uses a different mail server, then it is sent to their mail server before being delivered to their mailbox.

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Email Servers

You can put other things inside the envelope besides the letter. You might want to include a photo, CD, DVD, etc.

You can also send other things with an email. These are called ‘attachments’. They can be images (photo’s, faxes), videos, audio (music, recordings), etc.

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References

• How the Internet Works, Eighth Edition, By Preston Gralla (http://www.amazon.com/How-Internet-Works-8th/dp/0789736268/ref=pd_bbs_sr_1/105-1702276-1921200?ie=UTF8&s=books&qid=1190929493&sr=8-1)

• BroadbandInfo.com. Retrieved August 17, 2007, from website: http://www.broadbandinfo.com/internet-access/default.html

• Jeff Tyson (??) How Internet Infrastructure Works. Retrieved August 17, 2007, from website: http://computer.howstuffworks.com/internet-infrastructure.htm

http://www.amazon.com/How-Internet-Works-8th/dp/0789736268/ref=pd_bbs_sr_1/105-1702276-1921200?ie=UTF8&s=books&qid=1190929493&sr=8-1

http://www.amazon.com/How-Internet-Works-8th/dp/0789736268/ref=pd_bbs_sr_1/105-1702276-1921200?ie=UTF8&s=books&qid=1190929493&sr=8-1

http://www.broadbandinfo.com/internet-access/default.html

http://computer.howstuffworks.com/internet-infrastructure.htm

the internet - super highway

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