计算机网络是由计算机和通信两项技术结合而成的,它们各有十分复杂的历史和传统。20世纪中叶以来,发生了二个巨大变化:一是微电子学集成电路的发展,导致数字信号的处理成本大为下降,速度极大提高,二是庞杂的系统结构由于出现了可存贮的程序和程序设计语言,而取得了革命性的进展,计算机领域内的新概念和新技术可有效地用于通信领域。现在,我们已从技术角度上将计算机和通信二者结合到一起,它们共用同类的逻辑、存 Computer network is a combination of computer and communications technology, each of them has a very complex history and tradition. Two tremendous changes have taken place since the middle of the 20th century: First, the development of integrated circuits for microelectronics has led to a drastic drop in the cost of processing digital signals and a huge increase in speed. Second, the complicated system structure has emerged as a result of storable Program and programming language, and made a revolutionary progress, the computer field of new concepts and new technologies can be effectively used in the field of communications. Now that we have both technically combined computers and communications, they share the same kind of logic