说明：  描述了在VxWorks 操作系统下以太网设备工作时的结构层次,介绍在这种结构下以太网卡驱动的工作原 理以及对链路状态进行实时监测的方法. 实现了VxWorks 下多网卡共用单MAC 地址和单IP 地址的功能,并阐明 双网卡协同工作时的多种状态以及状态间的迁移和出现故障后双网卡高速切换原理. 最终以RTL8139 网卡为例, 叙述了双冗余网卡原理的实现过程.
(The working laying structure of the Ether Net device is described firstly based on vxWorks which is the real2 time operating system. Then the principle of the Ether Net card and the method of real2time monitoring link route status are introduced and the function of sharing the single MAC address and the single IP address on multiples cards is imple2 mented under the vxWorks. Thirdly , the many status which appear on two Ether Net cards working together and the shift among the status and the fast switch principle between two cards after failure are presented in details. Finally the method of how to use the two Ether Net cards implementing the redundancy function is given by taking the RTL8139 as an example.)