Cisco Networking Essentials

CHAPTER 3

TCP/IP

In 1969, the U.S. Department of Defense, acting through its Advanced Research Projects Agency (ARPA, now called DARPA) and in partnership with U.S. universities and the corporate research community, created a four-node network called the ARPANET. This baby step toward what is today known as the Internet used the Network Control Protocol (NCP). In 1974, when NCP proved incapable of handing the increasing amount of traffic, the design for a new set, or suite, of networking protocols was presented called Transmission Control Protocol/Internet Protocol (TCP/IP).

Over the next five years, the protocol went through four version updates. In 1979, version 4, which we have used until just recently and are still using in combination with ...