20世纪 6 0年代后期 ARPANET的研究成果引发了计算机网络的迅速发展。三十多年后的今天 ,计算机网络的应用已渗透到人类社会的各个领域 ,网络技术已成为信息技术的重要组成部分。二十一世纪将是信息时代 ,信息将与材料、能源一起构成了社会物质生产活动和精神生产活动的三大重 The research results of ARPANET in the late 1960s led to the rapid development of computer networks. More than thirty years later, the application of computer network has penetrated into all fields of human society. Network technology has become an important part of information technology. The 21st century will be the information age. Together with materials and energy, information will constitute the three major components of social material and spiritual activities