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All About The Internet  A
Little HistoryThe Internet began in the late 1960s. The U.S. Department of Defense DOD was concerned that in the event of a nuclear attack information couldn't be passed to our missile silos. It was decided that a network of interconnected computers could transfer information even if a portion of it was destroyed. The messages would be broken up into packets and switched through a network. Any bad or lost packets could be sent again. The ARPANET was the first packet switching network in 1968. Email started in the early 1970s. Development began on the protocol standard TCP/IP, which is the underlying transfer protocol used on the internet today. It allows diverse computer networks to interconnect and communicate with each other. USENET ,news group network, was created in 1979 and has grown. The network began storing information at the nodes to be transmitted later, "store and forward." In 1992 the World Wide Web specification was released. in 1994 you could order a pizza from Pizza Hut on its Web page . In 2002 Netopoly began offering low cost web pages to the masses. The rest is history.
Internet Structure Uniform
Resource Locator (URL)
Every server on the internet must have URL. This is the name. YourName.com. Every node on the Internet must know where the servers is for it to send the message on. To reduce the time it takes to look up every URL in the world there are Directory Name Servers, DNS. The DNS stores URLs for its portion of the Internet. All the nodes know which DNS to forward the message to. Once the message gets to the DNS the message is forwarded to the specific URL. This keeps routing calculations down. Please see Tutorials > Tutorial Links > Scripts and HTML > About the Internet. ICANN
The Internet Corporation (ICANN) is a non-profit, private-sector corporation. It Assignes Names and Numbers and is a technical coordination body for the Internet. Created in October 1998 by a broad coalition of the Internet's business, technical, academic, and user communities. ICANN coordinates the assignment of the following identifiers that must be globally unique for the Internet to function:
In addition, ICANN coordinates the stable operation of the Internet's root
server system.
Data Packet Transfer Before the information is sent to the Internet, it is be broken up into chunks called packets. Each packet has the origin, destination and sequence added in a packet header. Error detection codes are placed at the end of each packet. The packets are switched from computer to computer through the network until the final destination is achieved. Each of the computers or nods in the network must know where all of the destination are. When a node receives a packet it evaluates where it is going and decides on the most efficient rout. When the packets arrive at the destination they may not be in the same order and some packets may be lost. The receiving computer must put the packets in sequence and check each packet to ensure its data is correct. If there are missing or bad packets a request is sent back to the originator for the lost packets.
Clients and Servers There is a basic distinction between two types of devices that connect to the Internet. Clients request information from the Internet. Servers get the information and send it back. When we're talking about Web pages, the client requests Web pages and the server sends them back. The server can create Web pages dynamically or simply serve a static HTML file. Server side programming allows the page to be created on the server.
Web Services A Web service is the server that sends back information instead of a web page. This information is usually a portion of the database. For example the amount of a product in your inventory. At the time of this writing this is still in its infancy. However, in a very short period of time the business to business community will automate their infrastructure using Web services.
Search Engines When a person is browsing the web it's like looking through a huge catalog that has everything in the world in it. There are people out there that have made it their business to catalog everything on the Internet. This makes it easier to locate pages that you want to browse. These are called search engines. Allot of people find things through search engines. About 40% of web page traffic is through search engines.
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