以太网标准IEEE802.3规范，。一种网络协议。描述物理层和数据链路层的MAC子层的实现方法，在多种物理媒体上以多种速率采用CSMA/CD访问方式。(Ethernet standard IEEE802.3 specification. A network protocol. This paper describes the implementation method of MAC sublayer in physical layer and data link layer. CSMA/CD access mode is adopted in various physical media at different rates.)