The Internet: How it Works and How it Effects the World

Many people do not understand what the Internet is the power that it has over the world. The Internet is an extraordinary learning and entertainment tool that, when used properly, can significantly enhance a user's ability to gather information.
Advanced Research Projects Agency Network (ARPANET) started the Internet. It was a project under taken by the Department Of Defense (DOD) in 1969. It started as an experiment to link together DOD and military research including Universities doing military-funded research.
"The reliable networking part involved dynamic rerouting." (Levine 12) If one of the computers was under enemy attack, the information could be automatically transferred to other links. Fortunately, the Net is not usually under enemy attack.
The ARPANET was very successful, and every university in the country wanted to sign up. Because so many people wanted to use the Net, ARPANET started getting hard to manage, especially with many university sites on it. Therefore, it was broken into two parts: MILNET, which had all the military sites, and ARPANET, which had all the nonmilitary sites. "The two networks remained connected, however, thanks to a

technical scheme called IP (Internet Protocol), which enabled traffic to be routed from one net to another as needed. All the networks connected by IP in the Internet speak IP, so they can all exchange messages." (Levine 12)
Even though there were only two networks at that time, IP was made to allow thousands of networks. The IP is designed so that every computer on an IP network is compatible. That means any machine can communicate with any other machine.
The Internet, also called the Net, is the world's largest computer network. The Internet is the "network of all networks." (Levine 7) The networks are connected to big companies like AT&T, as well as to home computers. About 1,000 networks join each month.
Every computer that is attached to the Internet is called a host. Hosts can be super computers with thousands of users, regular PC's with only a couple of users, or specialized computers, like routers that connect networks together or to terminal servers that let terminals dial in and connect to other hosts.

Below is a chart of the Internet Host Growth from May 1982 to July 1994.





Each computer has its own host number. "Being computers, the kind of numbers hosts like are 32-bit binary numbers." (Hayden 32) Here is an example of a binary number:

1011010010010100100100101000


Binary numbers are easier to remember by breaking them up into eight 4-bit groups. "Then each group is translated into it's Hexadecimal equivalent." (Levine 18) So the number above would translate into this:
B.49.49.28
This number is easier to use and remember.
Every four digits in the binary number stands for one hexadecimal number. Below is a list of each four binary numbers and its hexadecimal equivalent.
BINARY HEX EQUIVALENT

0000 0
0001 1
0010 2
0011 3
0100 4
0101 5
0110 6
0111 7
1000 8
1001 9
1010 A
1011 B
1100 C
1101 D

1110 E
1111 F
To figure out the binary number in the example into its Hex equivalent is in this way:
1011 is the first four digits of the binary number. Looking at the table, it can be determined that its hexadecimal equivalent is a "B". The second set of four binary numbers is 0100. That changes into 4 and so on.
The first four numbers of a host number tells you what class the network is. The chart bellow states classes and sizes:


Class First Number Length of first Number Maximum Number of Hosts
A 1-126 1 16,387,064
B 128-191 2 64,516
C 192-223 3 254

Big companies like IBM and Apple usually have class A networks. "For example, IBM has network 9, and AT&T has network 12, so a host number 9.12.34.56 would be

at IBM, and 12.98.76.54 would be at AT&T." (Levine 19) Medium sized companies and universities have class B networks. "Rutgers University has network 128.6 and Goldman Sachs has network 138.8" (Levine 19) Small organizations use class C networks. Network 192.65.175, for example, is used by a single IBM research lab.
To make it easier the Internet uses names, not numbers. "For example, the machine we have heretofore referred to as 140.186.81.1 is named chico." (Levine 21)

When ARPANET first came out, they had simple names; the machine at Harvard was called HARVARD. But since there are millions of names on the Net they had trouble coming up with different names.
To avoid this problem they created the Domain Name System (DNS). Host names are strings of words separated with