该信息一般都出现在直接连接PC的交换机端口上。支持PXE(网络启动）的网卡在启动过程中往往会多次改变状态，而支持WOL（网络唤醒）的网卡在计算机关闭后仍可以可以保持UP状态，但一般都是半双工模式。如下log信息：

26 05:02:35 6 SWIT PINT UP Port1: interface is UP
＃Windows is loading and NIC driver is not loaded yet
26 05:02:37 6 SWIT PINT DOWN Port1: interface is DOWN
＃Windows takes NIC down and loads drivers
26 05:02:40 6 SWIT PINT UP Port1: interface is UP
＃Windows brings up and initialises NIC
26 05:03:04 6 SWIT PINT DOWN Port1: interface is DOWN
＃Windows binds TCP/IP and IP address to NIC
26 05:03:09 6 SWIT PINT UP Port1: interface is UP
＃Windows has booted with IP bound to NIC