说明： 中国计算机三级网络技术考过指南，其中包括作者备考三级时对知识点的总结，能领会贯通的多半都能过三级 (China's three-tier computer network technology has passed the examination guide, including the author's summary of knowledge points when preparing for the three-tier examination. Most of them can understand and pass the three-tier examination.)
