TCP/IP Overview When designing network applications, a key protocol is the foundation that makes this possible. This protocol is TCP/IP. There are many protocols that allow two applications to communicate. What makes TCP/IP an interesting protocol is that it allows applications on two physically separate computers to communicate. What makes TCP/IP great is that it can work with two computers spread across a room or across the world. In this article, I'll show you how TCP/IP allows a wide range of computer hardware to work together without ever having to know what the other machine is or how it works. At the same time, you will learn how it allows information to travel around the world in a fraction of a second without knowing in advance how to get there. Before we go too far, it's worth noting that TCP/IP is actually two protocols. . The first is the Transmission Control Protocol or TCP. The second protocol is IP which stands for Internet Protocol. These two elements combined form the basis of the virtual level of most networks we use today. The roots of these protocols date back to the 1970s. At that time, networks consisted of wires directly connecting one computer to another. This is called direct connection. If you want information to get to a computer that yours is not directly connected to, you will need to create a bridge to a common machine that you are both connected to. This way, messages you send in one connection are transferred from the computer to the other connection and sent to the computer you were trying to talk to. This is sometimes called a gateway.In 1973, the Defense Advanced Research Projects Agency (DARPA) commissioned two engineers to design a way for information to travel more easily between these early networks...... middle paper......ackages.This pair of protocols is the workhorse of the modern Internet. According to Microsoft, this is "largely due to its ability to connect networks of different sizes and systems of different types." ("Understanding the Basics of TCP/IP Addressing and Subnetting", September 23, 2011) Before the arrival of TCP/IP, machines had to be compatible at the physical level to be able to transmit messages between them. Now the physical level has been abstracted and messages pass through a logical layer. The physical layer is still there but it is now a solved problem space allowing developers to focus more on applications. This has become the real success story of TCP/IP.Works cited by Microsoft Inc., "Understanding the Basics of TCP/IP Addressing and Subnetting". Last modified September 23, 2011. Accessed September 24, 2011. http://support.microsoft.com/kb/164015.