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troubleshooting AIR-LAP1242AG disconnect to WLC 5508

Hi all,

     Please help with the following issue : I have these two AP units, among 44 units, connecting to WLC 5508 and worked fine for many months. Three days ago, they disconnected to the WLC. I telnet to the switch where these AP units cabling to and able to do ping to their ip addresses only if I do "shut/no shut" on those interfaces but only 60 secs later, I cannot ping them any more. WLC has no logs about these units. I cannot console into these AP units because they're thousand miles from me. Another thing is : sometimes those AP ip addresses got changed to different ip addresses than the static ones assigned to them. How that happens ? please educate me to fix this problem. Cisco TAC was involved but they require console access which I cannot do it right away. Thanks for all help.

Cisco Employee

actually the console log of

actually the console log of the AP is needed to check why the AP is got disconnected from the WLC, as we can't see any log on the WLC telling us why the AP disconnected , this could be happen due to power loss.


in the trap log you may see that the AP disjoin the WLC and reason: power loss.

but i done this that the issue is due to the power loss.


also the AP is renewing the ip address , this is a normal behavior for the AP , if the AP can find the WLC it will fallback to dhcp ip and renew the ip address , and it will do it for serveral times.



as we have a 5508 and AP in remote side , we need to check on the packet fragementation over the WAN,

as the 5508 does not support fragmented packets.


can you please try this from you PC(this pc should in the same subnet of the WLC), ping -l 119 -f <AP-ip> -t and see if any of the ping is need to be fragemented.also you need to do the same test at the AP side.


can you share #show ap config general Cisco_AP 

and a wired traces for the AP and the WLC sychronized , and re produce the issue.

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