C-1 Internet: what is it?

C-1 What is the Internet?

Students will learn about the internet, including how it was created and who controls it. They will then explore how it works through acting it out in a guided simulation.

Do Now (5 minutes)

TEACHER GUIDANCE:

• • The internet was invented in the 1970s, which was a result of the ARPANET which created a distributed network in which messages are sent via small blocks or packets.

  • The internet is made up of many independently operated networks with no central control but an understanding that anyone should be able to connect and communicate with anyone else.

Mini-Lesson (5-10 minutes)

This lesson has been adapted from the Code.org lesson “The Internet”

Introduce the new vocabulary for this lesson. Sending a message over the Internet is a lot like sending a message through the mail...if every letter we sent required thousands of envelopes!

Every message we send through the Internet gets chopped up and each piece is wrapped in its own version of an envelope. We call those "packets." Packets are specially formed chunks of information that are able to easily flow through any of the Internet's channels.

Sometimes, a few of those packets will get lost, because the Internet is a crazy place. In that case, the packets need to be resent, and the whole message has to get put on hold until they arrive.

Where do you think those packets are headed?

• • Even if you're sending messages to another person, they first have to go to at least one "server."

    • A server is a special computer that is supposed to be always on and ready to send and receive information.

    • Every website has a server.

    • Even email goes through servers.

Servers don't have names like you and I do. They're actually addressed using numbers. These numbers are called IP addresses, and they look a little strange.What kind of connection would you rather have (Wi-Fi, DSL/Cable, or Fiber Optic)? Why? Why might it take your message a long time to get somewhere?

• • For example: One of Code.org's IP addresses used to be 54.243.71.82

There are many ways to reach the Internet from your house, school, or place of business.

• • You can connect directly using a cable (that might be DSL, Cable, or Fiber Optic)

  • Or you can connect using radio waves over the air through Wi-Fi

Direct connections are most reliable, but they can be inconvenient.

• • Can you figure out why? (You have to be attached to a cable!)

Wi-Fi connections are super convenient, but the aren't always reliable.

• • Can you figure out why not? (Radio waves bounce all over the place and can get lost.)

So, if you're used to sending information to URLs (like www.code.org) and the servers actually have IP addresses for names (like 54.243.71.82) how does the Internet change from one to the other? That's what the DNS is for. The DNS (Domain Name Server) has tables that allow the system to go back and forth between URLs and IP addresses. If the Domain Name Servers ever stopped working, it would shut down the Internet as we know it!

(You may wish to use this video How the Internet Works in 5 Minutes to teach the above, stopping at 3:00.)

Create a DNS table using URLs recommended by the class, and using a site like http://get-site-ip.com to find the IP addresses for those sites.

TEACHER GUIDANCE:

Close-Out (5 minutes)

Discuss the following questions:

• • • What kind of connection would you rather have (Wi-Fi, DSL/Cable, or Fiber Optic)? Why?

    • Why might it take your message a long time to get somewhere?

Standards CSTA

• CSTA 2-NI-06: Apply multiple methods of encryption to model the secure transmission of information.

  • CSTA 2-NI-05: Explain how physical and digital security measures protect electronic information.

  • CSTA 2-NI-04: Model the role of protocols in transmitting data across networks and the Internet.