Assalamualaikum
Alhamdulillahirrabil alamin.
Gratitude we bid to Allah because giving us
another opportunity to live on this earth to worship Him
Today we will learn about history of internet, here are some story that we may understand.
In the late 1950's the Advanced Research Projects Agency (ARPA) was founded in the United States with the primary focus of developing information technologies that could survive a nuclear attack. In 1967 ARPA university and private sector contractors met with representatives of the Department of Defense to discuss possible protocols for sharing information via computers. In 1969, two years before the calculator was introduced to consumers ( History of the Internet and WWW ) and the year after National Public Radio was established, the precursor of the Internet, ARPANET, was born. It connected four sites at the University of California at Los Angeles, the University of California at Santa Barbara, Stanford Research Institute, and the University of Utah. Throughout the 1970's researchers concentrated on developing protocols for controlling networks, moving messages across a system of networks, and allowing for remote access to the networks. There were computers connected at about two dozen sites when the first email was sent in 1972, but the number of sites and messages soon mushroomed. By 1975 there were 63 sites. In 1980, 200 host computers were connecting 20,000 people at university, military, and government locations. Twelve years later the number of hosts had grown to more than a million internationally, and in January of 1999 there were more than 43 million. ( Hobbes' Internet Timeline v4.1 )
If the 1970's were a time of research, the 1980's were a time of development. The TCP/IP protocol was introduced in 1983, and at the University of Wisconsin the name server was developed. The next year domain name server (DNS) was established. In 1986, the National Science Foundation developed a system to connect the growing number of hosts. Regional networks were connected to a backbone network, which became known as the NSFNET. As the "Internet" continued to grow and prosper, ARPANET came to an end in 1989 just before HTML protocol was introduced in 1990. HTML allowed graphics to be sent along with text to create hypertext pages customized to the sender's preference. Everything was now in place for explosive growth.
HOW INTERNET WORK
Internet protocol
Every machine on the Internet has a unique identifying number, called an IP Address. The IP stands for Internet Protocol, which is the language that computers use to communicate over the Internet. A protocol is the pre-defined way that someone who wants to use a service talks with that service. The "someone" could be a person, but more often it is a computer program like a Web browser.
To make it easier for us humans to remember, IP addresses are normally expressed in decimal format as a dotted decimal numberlike the one above. But computers communicate in binary form. Look at the same IP address in binary:
The four numbers in an IP address are called octets, because they each have eight positions when viewed in binary form. If you add all the positions together, you get 32, which is why IP addresses are considered 32-bit numbers. Since each of the eight positions can have two different states (1 or zero), the total number of possible combinations per octet is 28 or 256. So each octet can contain any value between zero and 255. Combine the four octets and you get 232 or a possible 4,294,967,296 unique values!
Out of the almost 4.3 billion possible combinations, certain values are restricted from use as typical IP addresses. For example, the IP address 0.0.0.0 is reserved for the default network and the address 255.255.255.255 is used for broadcasts.
The octets serve a purpose other than simply separating the numbers. They are used to create classes of IP addresses that can be assigned to a particular business, government or other entity based on size and need. The octets are split into two sections: Net and Host. The Net section always contains the first octet. It is used to identify the network that a computer belongs to. Host (sometimes referred to as Node) identifies the actual computer on the network. The Host section always contains the last octet. There are five IP classes plus certain special addresses.
Here are some example how to using a binary digit.
| Number in base 2 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 |
| Number in base 10 | 256 | 128 | 64 | 32 | 16 | 8 | 4 | 2 | 1 |
