串行接口故障排错
l Serial x is down, line protocol is down
l Serial x is up, line protocol is down
l Serial x is up, line protocol is up (looped)
l Serial x is up, line protocol is down (disabled)
l Serial x is administratively down, line protocol is down
(Cisco 版本的 HDLC 是专有版本,它增加了一个协议类型字段。因此,Cisco HDLC 只能用于连接其它 Cisco 设备。)
转载于:https://blog.51cto.com/switch2011/1006027