某局点无线控制器WX5540H下AP多次偶发掉线，之后又重新上线

1.组网拓扑：

2.AP使用集中转发，上连核心交换机，AC旁挂在交换机上，交换机做dhcp服务器，网关也在dhcp服务器上

业务环境的部分AP突然掉线，掉线的AP随机不固定，并且掉线一段时间后又重新上线，无线业务只在内网部分

1.首先查看AP的下线原因

 ===============display wlan ap statistics tunnel-down-record=============== 

AP name                       AP ID   Tunnel down at  Tunnel Down Reason  

AP5-07                         44     10-20/08:49:11  Processed join request in Run state                

AP71                           253    10-20/08:49:10  Processed join request in Run state                

AP8-17                         86     10-20/08:49:10  Processed join request in Run state                

AP2-05                         12     10-20/08:49:10  Processed join request in Run state                

AP8-13                         84     10-20/08:49:09  Processed join request in Run state                

AP6-21                         64     10-20/08:49:08  Processed join request in Run state                

AP4-26                         131    10-20/08:49:08  Processed join request in Run state                

AP27                           209    10-20/08:49:08  Processed join request in Run state       

Processed join request in Run state：AC上定时器未超时前再次收到AP的请求上线报文，这种情况是指AP先主动断开连接

AP7-22                         166    10-17/11:16:59  Failed to retransmit message                       

AP5-26                         144    10-17/11:16:59  Failed to retransmit message                       

AP2-02                         102    10-17/11:16:59  Failed to retransmit message                       

AP2-16                         108    10-17/11:16:59  Failed to retransmit message                       

AP13                           195    10-17/11:16:59  Failed to retransmit message                       

AP2-19                         19     10-17/11:16:59  Failed to retransmit message                       

AP36                           218    10-17/11:16:58  Failed to retransmit message                       

AP4-22                         129    10-17/11:16:58  Failed to retransmit message                       

AP4-11                         33     10-17/11:16:58  Failed to retransmit message

Failed to retransmit message ：重传信息失败 

经确认，当掉线原因为Processed join request in Run state，Failed to retransmit message，Neighbor dead timer expired（AC在三倍的握手时间内没有收到AP的Echo request报文，此时AC认为AP已经断开）一般都是由链路问题导致AP掉线

2.因为掉线AP不固定所以可以初步排除是AP自身问题导致掉线

3.在故障发生时，查看AC的CPU是否异常，排查是否有异常流量冲击AC导致AP掉线

1.故障时排查有线侧AC和AP的连通性（或者AP供电是否稳定）

2.查看故障发生时AC 的接口流量统计，是否有明显的单播或者广播流量突发的情况，确认是否有异常流量冲击AC CPU

排查链路没有问题，之后对供电环境进行测试，发现供电环境不稳定导致AP下线，更换供电环境后问题解决。