问题描述
故障现象：OSPF邻居出现了震荡导致路由反复收敛，流量转发不正常。
告警信息
无
处理过程
1 检查接口网段是否一致
2 检查各接口的优先级是否有非零
3 检查各路由器的route id互不相同
4 接口的timer等参数保持一致
5 接口的认证信息保持一致
6 检查是否ospf报文能正确接收
根因
光纤或光模块异常导致链路不稳定（链路频繁UP/DOWN），导致OSPF邻居状态不稳定。
解决方案
1 查看交换机的日志
从日志中可以看出用户报告的业务出现故障的时间点，有OSFP邻居DOWN的日志如下：
Feb 15 2014 14:27:54 SW_CASA_S9306_01 %%01OSPF/6/NBR_DOWN_REASON(l): Neighbor state leaves full or changed to Down. (ProcessId=100，NeighborRouterId=192.168.20.6, NeighborAreaId=0, NeighborInterface=Vlanif305,NeighborDownImmediate reason=Neighbor Down Due to 1-Wayhello Received, NeighborDownPrimeReason=1-Wayhello Received, NeighborChangeTime= [2014/02/15] 14:27:54) 类似的记录很多，OSPF邻居DOWN的原因都是收到1-way hello报文
2 查看NE40E设备的日志
发现在相同的时间点也有OSPF邻居DOWN的记录：
Feb 15 2014 13:26:31 PE_NE40E_CASA_ANWAL_01 %%01OSPF/6/NBR_DOWN_REASON(l)[67934]:Neighbor state leaves full or changed to Down. (ProcessId=202, NeighborRouterId=192.168.28.225, NeighborAreaId=0, NeighborInterface=GigabitEthernet8/0/0.305,NeighborDownImmediate reason=Neighbor Down Due to Kill Neighbor, NeighborDownPrimeReason=Physical Interface State Change, NeighborChangeTime=[2014/02/15] 13:26:31)