In order for a computer to connect to another, it needs a system just like how telephones need numbers to connect to each other. The Internet Protocol (IP) is the number designated to a computer in the network in order for others to pinpoint and connect to it. Since numbers are harder to remember, Domain Name System (DNS) was created in 1983 by the University of Wisconsin. A DNS is an IP address that is translated by the computer so that it can be understood by humans. Example of Domain is www.google.com this Domain also has a numerical equivalent down to a binary version which only the computer can easily decode. So instead of a user trying to type in the website's IP address, they simply type the domain name.
On the DNS system, when a user computer types www.abcdefg.com, the network will contact the DNS server and ask if there is one registered and which server it will ultimately lead to. For example if the DNS server is located in California, the DNS server will find the name requested, and on that data base, the ultimate address of the physical files of the website will be given. If the DNS in California states that www.abcdefg.com has its files located on a host server in Utah, then the computer will download the website from that host server.
Network Service Providers
Verizon Communications (NYSE : VZ) United States
Sprint Nextel (NYSE:S) United States
Quest communications International Inc.(NYSE: Q) United States
AT&T (NYSE: T) United States
AboveNet Inc. (NYSE: ABVT) United States
Cable & Wireless Worldwide PLC. (LSE: CW) United Kingdom
Tata Communications Ltd. (NYSE: TCL) India
Level 3 Communications (NASDAQ: LVLT) United States