"The Internet... allows [us] at each level of the network to innovate free of any central control."
Vinton Cerf
When we send files or e-mails to others over the Internet, few of us care how our messages arrive, almost instantaneously, at a distant terminal, with no direct connection between the two. But without the decentralized magic of Transmission Control Protocol (TCP) and Internet Protocol (IP), these remarkable events would not be possible. TCP and IP are separate networking protocols, but so intimately linked in use that they are generally referred to as a single entity.
Developed by Robert Kahn (b. 1938), Vinton Cerf (b. 1943), and others, and initially used on the U.S. Government's Advanced Research Projects Agency (ARPA) packet-switching network in 1983, TCP and IP permitted an ever growing number of remote networks to connect to each other and ultimately mature into the Internet. In essence, TCP and IP is "layered." The higher (TCP) layer concerns itself with dividing files or messages into smaller chunks, or "packets," for transmission, and reassembling received packets into their original form. The lower (IP) layer deals primarily with addressing and routing each packet so that it gets to the proper destination. The routes via which the parts of each message travel may well be different to each other. It is a bit like sending the pages of a book separately, via different routes, to an address at which they are then reassembled.
