故障情況：
APC11-AP04#sho capwap ip config
LWAPP Static IP Configuration
IP Address 172.17.239.204
IP netmask 255.255.255.0
Default Gateway 172.17.239.254
Primary Controller 172.16.245.29
APC11-AP04#
Translating "CISCO-CAPWAP-CONTROLLER"...domain server (255.255.255.255)
APC11-AP04#capwap ap ip add 172.17.239.204 255.255.255.0 172.17.239.254
^
% Invalid input detected at '^' marker.
APC11-AP04#
Translating "CISCO-CAPWAP-CONTROLLER"...domain server (255.255.255.255)
APC11-AP04#capwap ap ip add 172.17.239.204 255.255.255.0?
A.B.C.D
APC11-AP04#capwap ap ip add 172.17.239.204 255.255.255.0
You should configure Domain and Name Server from controller CLI/GUI.
APC11-AP04#
APC11-AP04#cap
APC11-AP04#capwap
Translating "CISCO-CAPWAP-CONTROLLER"...domain server (255.255.255.255)
Translating "CISCO-CAPWAP-CONTROLLER"...domain server (255.255.255.255)
% Incomplete command.
APC11-AP04#capwap ap primary-base GTMC-DLR-WLC-01 172.16.245.29
APC11-AP04#
APC11-AP04#
APC11-AP04#
APC11-AP04#
APC11-AP04#
APC11-AP04#ping 172.16.245.29
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.16.245.29, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 20/21/24 ms
APC11-AP04#
APC11-AP04#
APC11-AP04#
APC11-AP04#
APC11-AP04#
*Mar 1 00:08:29.323: AP has SHA2 MIC certificate - Using SHA2 MIC certificate for DTLS.
Writing out the event log to flash:/event.log ...
APC11-AP04#
APC11-AP04#
*Aug 6 11:11:53.000: %CAPWAP-5-DTLSREQSEND: DTLS connection request sent peer_ip: 172.16.245.29 peer_port: 5246
*Aug 6 11:11:53.275: %CAPWAP-5-DTLSREQSUCC: DTLS connection created sucessfully peer_ip: 172.16.245.29 peer_port: 5246
*Aug 6 11:11:53.275: %CAPWAP-5-SENDJOIN: sending Join Request to 172.16.245.29
如上情況這個AP發生了重啟，且重啟后沒有使用默認的IOS啟動，而是使用了統自帶的恢復鏡像。說明，此AP的磁盤可能發生損壞。
Loading "flash:/ap3g2-rcvk9w8-mx/ap3g2-rcvk9w8-xx"...########################
File "flash:/ap3g2-rcvk9w8-mx/ap3g2-rcvk9w8-xx" uncompressed and installed, entry point: 0x1003000
executing...
具體操作和說明：
1，根據現有的日志，能看到AP使用的是recover的鏡像來啟動的。
2，原有鏡像無法啟動的原因，可能是由於鏡像損壞。
3，根據經驗，AP如果啟動原有的鏡像失敗，啟動新鏡像時會丟失WLC的name。
4，如果故障再次發生的話，可以將AP的flash格式化，然后重新導入鏡像來嘗試恢復，也可以通過從WLC重新下載鏡像的方式覆蓋掉原有的鏡像。
格式化的命令如下：
Fsck flash:
鏡像恢復：
ap: ether_init
ap: flash_init
ap: tftp_init
ap: set IP_ADDR
ap: set NETMASK
ap: set DEFAULT_ROUTER
ap: tar -xtract tftp://< server ip address >/< image name > flash:
example:
tar -xtract tftp://10.124.40.59/ap3g2-k9w8-tar.153-3.JD.tar flash:
ap: boot flash:/< mage dir >/< image name >
example:
Boot flash:/ap3g2-k9w8-mx.153-3.JD/ap3g2-k9w8-mx.153-3.JD