The Transmission Control Protocol (officially TCP/IP but referred to as TCP throughout the rest of this book) is the workhorse of the Internet. First defined in 1974, it builds upon the packet transmission technology of the Internet Protocol (IP, described in Chapter 1) to let applications communicate using continuous streams of data. Unless a connection dies or freezes because of a network problem, TCP guarantees that the data stream will arrive intact, without any information lost, duplicated, or out of order.
Protocols that carry documents and files nearly always ride atop TCP. This includes the delivery of web pages to your browser, ...