请大家帮忙分析一个中兴EPON的问题

hrmdadi

近日遇到一个奇怪的故障，中兴C200下挂的F822型ONU经常上报离线告警，密度非常大，但实际上在OLT侧观察ONU在线，并且PING也通，宽带业务时好时坏，但是坏的时候几分钟就能恢复，由于时间太短，又没有时间在OLT上一直观察，所以先将ONU替换掉了，替换以后就没有告警了，而且替换下来的ONU安装到别的地方也不产生告警，测量尾纤光功率-18DB。

告警信息如下：请大家帮忙分析一下是何原因？？？？

An alarm 43016 level 5 occurred at 11:24:16 01/10/2011 UTC  sent by MCP  Epon a
larm OnuOffLine: shelf 0 slot 1 olt 3 onu 2 level 5
on
An alarm 43016 level 1 occurred at 11:24:14 01/10/2011 UTC  sent by MCP  Epon a
larm OnuOffLine: shelf 0 slot 1 olt 3 onu 2 level 1
on
An alarm 43016 level 5 occurred at 11:24:06 01/10/2011 UTC  sent by MCP  Epon a
larm OnuOffLine: shelf 0 slot 1 olt 3 onu 2 level 5
on
An alarm 43016 level 1 occurred at 11:24:04 01/10/2011 UTC  sent by MCP  Epon a
larm OnuOffLine: shelf 0 slot 1 olt 3 onu 2 level 1
on
An alarm 43016 level 5 occurred at 11:23:56 01/10/2011 UTC  sent by MCP  Epon a
larm OnuOffLine: shelf 0 slot 1 olt 3 onu 2 level 5
on
An alarm 43016 level 1 occurred at 11:23:53 01/10/2011 UTC  sent by MCP  Epon a
larm OnuOffLine: shelf 0 slot 1 olt 3 onu 2 level 1
on
An alarm 43016 level 5 occurred at 11:23:48 01/10/2011 UTC  sent by MCP  Epon a
larm OnuOffLine: shelf 0 slot 1 olt 3 onu 2 level 5
on
An alarm 43016 level 1 occurred at 11:23:46 01/10/2011 UTC  sent by MCP  Epon a
larm OnuOffLine: shelf 0 slot 1 olt 3 onu 2 level 1
on      
An alarm 43016 level 5 occurred at 11:23:41 01/10/2011 UTC  sent by MCP  Epon a
larm OnuOffLine: shelf 0 slot 1 olt 3 onu 2 level 5
on
An alarm 43016 level 1 occurred at 11:23:39 01/10/2011 UTC  sent by MCP  Epon a
larm OnuOffLine: shelf 0 slot 1 olt 3 onu 2 level 1
on
An alarm 43016 level 5 occurred at 11:23:34 01/10/2011 UTC  sent by MCP  Epon a
larm OnuOffLine: shelf 0 slot 1 olt 3 onu 2 level 5
on
An alarm 43016 level 1 occurred at 11:23:16 01/10/2011 UTC  sent by MCP  Epon a
larm OnuOffLine: shelf 0 slot 1 olt 3 onu 2 level 1
on
An alarm 43016 level 5 occurred at 11:21:31 01/10/2011 UTC  sent by MCP  Epon a
larm OnuOffLine: shelf 0 slot 1 olt 3 onu 2 level 5
on