交换机与光端机连接故障，请帮忙！

Robinhood

故障描述：\r\n光端机的17个10 BaseT 以太口分别连接一台Cisco 2950交换机的17个端口，初始化后失去连接，在交换机上观察到以下信息（以F0/5为例，所有其它16个口与此相同。但与其它设备相联的端口工作正常）：\r\n\r\n系统提示：\r\n00:00:30: %ETHCNTR-3-HALF_DUX_COLLISION_EXCEED_THRESHOLD: Half-duplex loopback detected, collision threshold exceeded on FastEthernet0/5.\r\n00:00:30: %PM-4-ERR_DISABLE: loopback error detected on Fa0/5, putting Fa0/5 in err-disable state\r\n\r\nshow interface显示：\r\nFastEthernet0/5 is down, line protocol is down (err-disabled)\r\n  Hardware is Fast Ethernet, address is 000d.bdc8.9d05 (bia 000d.bdc8.9d05)\r\n  MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec, \r\n     reliability 249/255, txload 1/255, rxload 1/255\r\n  Encapsulation ARPA, loopback not set\r\n  Keepalive set (10 sec)\r\n  Auto-duplex, Auto-speed\r\n  input flow-control is off, output flow-control is off\r\n  ARP type: ARPA, ARP Timeout 04:00:00\r\n  Last input never, output 00:02:05, output hang never\r\n  Last clearing of \"show interface\" counters never\r\n  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0\r\n  Queueing strategy: fifo\r\n  Output queue :0/40 (size/max)\r\n  5 minute input rate 0 bits/sec, 0 packets/sec\r\n  5 minute ouxtput rate 0 bits/sec, 0 packets/sec\r\n     3 packets input, 192 bytes, 0 no buffer\r\n     Received 2 broadcasts, 0 runts, 0 giants, 0 throttles\r\n     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored\r\n     0 watchdog, 0 multicast, 0 pause input\r\n     0 input packets with dribble condition detected\r\n     1 packets output, 960 bytes, 0 underruns\r\n     14 output errors, 28 collisions, 2 interface resets\r\n\r\n所有端口速率为Auto-duplex, Auto-speed；把端口改成Auto-duplex, 10Mb/s或Half-duplex, 10Mb/s情况都一样。

流浪的狗

FastEthernet0/5 is down, line protocol is down (err-disabled) \r\n表示链路层协议没同步。\r\n第一检查物理层的电气参数，\r\n第二检查光端机链路层的协议参数配置

Robinhood

我们发现把光端机上的卡热拔插一下，故障就消除了。于是就把17块卡都拔出再插上，果然每个端口都正常工作了。\r\n但是交换机只要一重启，上述拔插工作就要重新来一遍，否则就如原帖那样报错。