What is the Internet?

1 period

AIM

What is the Internet?

LESSON OBJECTIVES

Students will be able to:
• List the component parts of the Internet.  
• Restate the history of the Internet.

TEACHER BACKGROUND

This lesson and the following lesson cover the components of the Internet, a rough overview of how it works, and how it came to be. This lesson is designed to expose the students primarily to the history and components of the Internet. The next lesson allows students to apply those component parts as a precursor to using a browser in following lessons.

A lot of students will want to start right away by jumping on the computers. While there is much to be said for discovery, in this case many students will really need some background information before they can start using the Internet.

The Internet has certain quirks and limitations that have grown out of many years of evolution, and has more facets than just the World Wide Web. This portion of the Internet cluster of lessons gives your students sufficient exposure to the Internet as a whole to allow them to appreciate its value and more efficiently use its resources.

It is worth noting that the Internet was due to Cold War tensions. The former Soviet Union was in a position to group its scientists in order for them to work more efficiently and, as a result, was able to put the first artificial satellite into orbit before the United States could do so in 1957. The United States was concerned that, if the Soviets could put a radio into space, they could deliver atomic weapons as well. At the time, the vast majority of the military’s communications was very centralized, and a well-placed strike would destroy the military’s ability to communicate or react. The need then became to develop a system that would provide the scientists and the military a mechanism for exchanging information.

Eventually many companies that worked with the Department of Defense were included in the network of computers soon to be known as the Internet, and they chose to stay connected even after the military pulled out to create its own network. That was the beginning of a system that was no longer run by the government, but by businesses and people who needed a better way to exchange information.

Hobbes’ Timeline is a document on the Internet. At the end of these grouped lessons, students will look at the original on-line, as well as at many other sites that will fill in their knowledge of the Internet. But, before they can understand the significance of some of the innovations, we’ll need to put a few of the major entries in context.

MATERIALS

• Timeline - Worksheet #1 (CAIT.InternetI.1.1.pdf)  
• TCP/IP - Worksheet #2 (CAIT.InternetI.1.2.pdf)  
• Teacher Supplement (CAIT.InternetI.1.3.pdf)  
• Teacher Background Supplement(CAIT.InternetI.2.1.pdf)

SPRINGBOARD

>>>>> What event in our history do you suppose was sufficiently impressive to convince the United States government to invest millions of dollars and untold man-hours in building the Internet?
Elicit the responce: The launch of Sputnik in 1957.

>>>>> How long do you suppose the Internet has existed?
Elicit the responce: Since the 1960s.

>>>>> What do you think makes up the Internet?
Elicit the responce: Many different functional areas make up the Internet.

LESSON DEVELOPMENT

‘When we discuss the Internet, normally we think about the ‘web’ and all of the dot-com sites. But let’s look at what is actually going on. Your computer connects to another computer, and they share some information. How is it that your computer ‘understands’ another computer, even if it is a different kind? How did that information get on the Internet? How was that information delivered to your computer? And, how did you know where to find the information in the first place?’

>>>>> ‘How does TCP/IP work?’

Have students fill out two or three copies of the TCP/IP worksheet. On each sheet they should put their names in the ‘from’ blanks, put a classmate’s name in the ‘to’ blanks, and then write a message, one word per block. When this is done, have the students fill in the total number used in each block and cut up the sheet into separate blocks. TCP only can move small bits of information, so IP is used to pack the message in more usable blocks.

Mix up all the separate sheets; give them at random to students who will then ‘forward’ the message blocks by passing them from student to student. They do not have to take the shortest path; the key is to distribute the message to carriers that are not busy. When the recipient has all the pieces, they reassemble the messages.

Variation. Hold back one or two random message blocks until the students notice and ask for the missing portions by sequence number. This demonstrates the error correction abilities of IP.

Variation. Tell one student not to accept messages for forwarding. Does the mail still go through? Yes, because of the decentralized nature of TCP/IP. The only time a message doesn’t go through is when the sender or receiver is not connected. And, if the receiver is off line, the message stays in circulation until the receiver reconnects.

‘Because much of the Internet’s traffic flows over phone lines, many people believe that all the information follows one path straight from the sender to the receiver immediately, just as a phone call works. That is called circuit-switched delivery. But, in fact, the Internet works more like the post office, moving information by different routes when a carrier is available to pick up and forward. This is called packet-switched delivery. The only difference between the post office and the Internet is that the whole process may take less than a second to break, distribute, collect, and reassemble a message whose parts may have gone through Texas and Japan on the way.’

‘The answers are protocols, such as telnet to translate, ftp to copy data to the server, TCP/IP to download, and search engines that help keep track of millions of documents.’

‘Each of the actions that now seem automatic had to be invented. Most of the inventions were created separately, and only recently were they all thrown together. So perhaps you can better use your browser if you see what components are there and why they came about.’

‘Let’s start with a short version of Hobbes’ Timeline and take a look at some of the big events.’

‘There are some interesting trends to note when we go over the timeline. First, from the time the problem of decentralized communication became apparent in 1957 until a design was published, 10 years had elapsed. But at that point, time frames start to compress. The time elapsed from the first crude search engine, Archie in 1990, until the birth of the web in 1992-19933 was only months.’

‘It is interesting to note that today many hundreds of computers connect to a few server computers; in 1971 only 15 user computers (nodes) could connect to 23 Internet servers. That is, more computers held information than computers that could access that information on the ARPAnet.’

‘It is also interesting to note that the Queen of England beat the President of the United States to e-mail by some 15 odd years.’

‘TCP/IP is the basis for Internet communication. When participating on the Internet, you have many options-- any number of pieces of hardware such as a computer or cell phone with a physical or wireless connection to the Internet, at least one of a variety of software tools, such as telnet, ftp, or a browser-- but you must have TCP/IP.’

>>>>> ‘How does TCP/IP work?’

Have students fill out two or three copies of the TCP/IP worksheet. On each sheet they should put their names in the ‘from’ blanks, put a classmate’s name in the ‘to’ blanks, and then write a message, one word per block. When this is done, have the students fill in the total number used in each block and cut up the sheet into separate blocks. TCP only can move small bits of information, so IP is used to pack the message in more usable blocks.

Mix up all the separate sheets; give them at random to students who will then ‘forward’ the message blocks by passing them from student to student. They do not have to take the shortest path; the key is to distribute the message to carriers that are not busy. When the recipient has all the pieces, they reassemble the messages.

Variation. Hold back one or two random message blocks until the students notice and ask for the missing portions by sequence number. This demonstrates the error correction abilities of IP.

Variation. Tell one student not to accept messages for forwarding. Does the mail still go through? Yes, because of the decentralized nature of TCP/IP. The only time a message doesn’t go through is when the sender or receiver is not connected. And, if the receiver is off line, the message stays in circulation until the receiver reconnects.

‘Because much of the Internet’s traffic flows over phone lines, many people believe that all the information follows one path straight from the sender to the receiver immediately, just as a phone call works. That is called circuit-switched delivery. But, in fact, the Internet works more like the post office, moving information by different routes when a carrier is available to pick up and forward. This is called packet-switched delivery. The only difference between the post office and the Internet is that the whole process may take less than a second to break, distribute, collect, and reassemble a message whose parts may have gone through Texas and Japan on the way.’

>>>>> ‘Why do you suppose a straight connection from sender to receiver is not used on the Internet?’

‘The answer is: Much of the time when you are on the Internet, nothing is being transferred, such as when you are reading a page. It would be wasteful to tie up a line. Also recall that one of the major reasons to build the Internet was to get away from centralized communications. Any number of routes can be used, even if a particular station is not working.’

‘We think that the Internet is growing rapidly today, but notice that in the late 1980s and early 1990s it grew by a factor of 10 every year and a half or so, indicated by the number of host, or information-serving computers.’

>>>>> ‘Why do you think the Internet grew so rapidly then?’

‘The answer is that more computers, especially personal computers, were available and easier to use software was being developed.’

To tie this lesson to the end of the cluster of lessons, ask:
>>>>> ‘How many computers are on the Internet now?’ This can be searched for during Internet lesson IV.

‘It is often difficult to understand the abilities or limitations of a phenomenon unless you see how it developed. The Internet turned 30 in 1999. When did you first hear about this ‘overnight’ success?’

The military has its own network now, and colleges are now creating their own separate network, called Internet II.’

>>>>>‘Who is using the ‘old’ Internet now?’

‘Individuals and businesses now make up the bulk of Internet traffic.’

SUMMARY

>>>>> Today we learned a little about how the Internet grew by looking at when various people and protocols were added to the foundation. Why was the Internet started?

>>>>> What is required to participate on the Internet?

>>>>> How does TCP/IP work?

APPLICATION

>>>>> In sequence, list 5 or 10 major developments in the Internet and explain why these steps were important.

>>>>> The Internet has seen many changes over many years, but it still is too slow and inefficient for some people. Do you think it could be quickly replaced? Why or why not?

HOMEWORK

In the next lesson, we will spend more time discussing how the Internet evolved from a government-run network to what it is today. One of the key issues is that the United States government no longer runs the Internet. What kind of structure do you suppose is now in place to oversee this new community of millions?

Have the students consider the problem and develop one or two ideas of how they think the Internet could be managed. Have them bring their ideas to the next lesson to compare to the actual structure of the governing system now in place for the Internet.