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Spinal-Injury.net : Internet Guide

 
Internet Guide - In the Beginning
Sometime in the mid 1960’s, during the Cold War, it became apparent that there was a need for a bombproof communications system. A concept was devised to link computers together throughout the country. With such a system in place large sections of the country could be nuked and messages could still get through.

In the beginning, only government “think tanks” and a few universities were linked. Basically the Internet was an emergency military communications system operated by the Department of Defence's Advanced Research Project Agency (ARPA). The whole operation was referred to as ARPANET.

In time, ARPANET computers were installed at every university in the United States that had defence related funding. Gradually, the Internet had gone from a military pipeline to a communications tool for scientists. As more scholars came online, the administration of the system transferred from ARPA to the National Science Foundation.

Years later, businesses began using the Internet and the administrative responsibilities were once again transferred.

At this time no one party “operates” the Internet, there are several entities that “oversee” the system and the protocols that are involved.

The speed of the Internet has changed the way people receive information. It combines the immediacy of broadcast with the in-depth coverage of newspapers…making it a perfect source for news and weather information.


Internet Guide - How It Works

For the purpose of this example let’s say that you want to send a file to a friend who lives on the opposite side of the country. You select the file that you friend wants and you send it to him via email. Transmission Control Protocol / Internet Protocol (TCP/IP) prepares the data to be sent and received. TCP/IP ensures that a Macintosh network can exchange data with a Windows, or a Unix network, and vice-versa.

The file that you are sending does not travel to your friends computer directly, or even in a single continuous stream. The file you are sending gets broken up into separate data packets. The Internet Protocol side of TCP/IP labels each packet with the unique Internet address, or IP address of your friends computer. Since these packets will travel separate routes, some arriving sooner than others, the Transmission Control Protocol side of TCP/IP assigns a sequence number to each of packets. These sequence numbers will tell the TCP/IP in your friends computer how to reassemble the packets once he receives them. Amazingly, the complicated process of TCP/IP takes place in a matter of milliseconds.

The packets are then sent from one “router” to the next. Each router reads the IP address of the packet and decides which path will be the fastest. Since the traffic on these paths is constantly changing each packet may be sent a different way.

The packets are then sent from one “router” to the next. Each router reads the IP address of the packet and decides which path will be the fastest. Since the traffic on these paths is constantly changing each packet may be sent a different way.

It is possible to discover the paths between routers using a utility known as Traceroute. Using your favourite search engine, type in “traceroute” to find different Web sites hosting it.

 

 


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