TABLE OF CONTENTS While OSI introduced the idea a framework for compatibility and modular flexibility, those ideas came to fruition in the Transmission Control Protocol/Internet Protocols (TCP/IP). Vinton Cerf and Robert Kahn originally developed TCP/IP in the early 1970s for use in ARPANET, the first packet switching network. While the first major applications on ARPANET were time sharing access and email, even in those early years the developers were discussing the potential of using packet switching technology to support voice. Today, TCP/IP has become the dominant protocol set for all data communications. For more information on the early development of the Internet and TCP/IP, go to http://www.isoc.org/internet/history/brief.shtml.
TCP/IP is not simply two protocols, but an entire set of inter-networking protocols and functional definitions. TCP/IP describes its own layered model akin to OSI, but it uses four rather than seven layers. TCP/IP does not replace protocols like Ethernet and Wi-Fi, but rather defines their roles within its overall model. The bottom line is that TCP/IP delivers the type of multi-vendor solution that the OSI planners had envisioned.
OSI provided a standard vocabulary for addressing compatibility problems, but practicality demanded a simpler model for implementation, and TCP/IP was just the thing. The convenient term TCP/IP is simply the names of two of over a hundred protocols that comprise the TCP/IP architecture. However, when we implement TCP/IP, we actually implement the entire architecture and the various protocols it is made of. One way to think of TCP/IP is an...
