AP注册不上线（现网中存在其它厂商的控制器）
在网络中存在两台控制器MSG360(192.168.0.223)和TP-LINK AC(192.168.0.253)
AP是华三的WAP712C

1、排错思路：
1）DHCP是在MSG360上，首先在AP查看是否能获取地址
AP可以获取地址
此处配置没有记录

2）在AP上查看capwap debug信息
从AP的debug信息可以看出，虽然MSG360(192.168.0.223)有发送discovery response过来，但是AP还是选择了TP-LINK AC(192.168.0.253)作为控制器进行注册，因为是TP-LINK的控制器，AP注册不上去，所以AP报错提示：Failed to load SSL certificates,uiAPID = 1. 然后进入Enter Sulking state，后变成 Enter Idle state。

WAP712C的capwap debug信息：


*Jan  1 00:04:42:931 2014 H3C CWC/7/RCV_PKT: Received discovery response with SeqNum 0 from AC at 192.168.0.223:5246.
*Jan  1 00:04:42:931 2014 H3C CWC/7/RCV_PKT: Verbose info for discovery response from AC 192.168.0.223:5246, length=128.
 00 10 02 00 00 00 00 00 00 00 00 02 00 00 73 00
 00 01 00 31 00 00 FF FF 00 02 00 14 00 02 00 02
 00 00 00 00 00 04 00 04 00 00 00 41 00 00 00 00
 00 05 00 03 39 39 00 00 00 00 00 01 00 00 06 04
 40 A9 2E 3B A8 00 04 00 12 57 69 72 65 6C 65 73
 73 43 6F 6E 74 72 6F 6C 6C 65 72 04 18 00 05 01
 00 00 00 0A 04 18 00 05 02 00 00 00 0D 00 25 00
 0F 00 00 63 A2 00 80 00 01 04 00 00 00 02 00 01
.
*Jan  1 00:04:42:932 2014 H3C CWC/7/RCV_PKT: Received discovery response with SeqNum 0 from AC at 192.168.0.223:5246.
*Jan  1 00:04:42:932 2014 H3C CWC/7/RCV_PKT: Verbose info for discovery response from AC 192.168.0.223:5246, length=128.
 00 10 02 00 00 00 00 00 00 00 00 02 00 00 73 00
 00 01 00 31 00 00 FF FF 00 02 00 14 00 02 00 02
 00 00 00 00 00 04 00 04 00 00 00 41 00 00 00 00
 00 05 00 03 39 39 00 00 00 00 00 01 00 00 06 04
 40 A9 2E 3B A8 00 04 00 12 57 69 72 65 6C 65 73
 73 43 6F 6E 74 72 6F 6C 6C 65 72 04 18 00 05 01
 00 00 00 0A 04 18 00 05 02 00 00 00 0D 00 25 00
 0F 00 00 63 A2 00 80 00 01 04 00 00 00 02 00 01
.
*Jan  1 00:04:44:932 2014 H3C CWC/7/TMR: Discovery Interval timer expired.uiAPID = 1.
*Jan  1 00:04:44:933 2014 H3C CWC/7/EVENT: Discovered AC by method of IPv4 broadcast successfully.
*Jan  1 00:04:44:933 2014 H3C CWC/7/EVENT: AP selected AC IP 192.168.0.253 Priority 0 successfully.
*Jan  1 00:04:44:935 2014 H3C CWC/7/ERROR: Failed to load SSL certificates,uiAPID = 1.
*Jan  1 00:04:44:935 2014 H3C CWC/7/FSM: Enter Sulking state.
*Jan  1 00:04:46:932 2014 H3C CWC/7/TMR: Silent Interval timer expired.
*Jan  1 00:04:46:933 2014 H3C CWC/7/FSM: Enter Idle state.
*Jan  1 00:04:46:933 2014 H3C CWC/7/EVENT: Start ipv4 dhcp opt43 discover.
*Jan  1 00:04:46:933 2014 H3C CWC/7/EVENT: Start ipv4 broadcast discover.
*Jan  1 00:04:46:942 2014 H3C CWC/7/EVENT: Open capwap client udp port:50048
*Jan  1 00:04:46:942 2014 H3C CWC/7/FSM: Enter Discovery state.
*Jan  1 00:04:46:943 2014 H3C CWC/7/EVENT: Fill discover req.wtu=1.model=WAP712C.wt drv info:[].subslot=0.licensetype=1.ret=0x40010001.
*Jan  1 00:04:46:943 2014 H3C CWC/7/EVENT: Fill discover req.ap=1.model=WAP712C.licensetype=1.carry wt info is unnecessary.
*Jan  1 00:04:46:944 2014 H3C CWC/7/SND_PKT: Sent discovery request with SeqNum 0 to AC 255.255.255.255:5246.
*Jan  1 00:04:46:944 2014 H3C CWC/7/SND_PKT: Verbose info for discovery request sent to AC 255.255.255.255:5246, length=155.
 00 10 02 00 00 00 00 00 00 00 00 01 00 00 8E 00
 00 14 00 01 00 00 26 00 3A 00 00 63 A2 00 00 00
 07 57 41 50 37 31 32 43 00 01 00 14 32 31 39 38
 30 31 41 30 58 35 39 31 38 31 47 30 30 30 4B 31
 00 03 00 05 56 65 72 2E 41 00 04 00 06 48 BD 3D
 63 AD 60 00 27 00 28 04 04 01 01 00 00 00 00 63
 A2 00 00 00 01 41 00 00 63 A2 00 01 00 05 52 32
 32 32 31 00 00 63 A2 00 02 00 04 37 2E 31 31 00
 29 00 01 0E 00 2C 00 01 02 04 18 00 05 01 00 00
 00 0A 04 18 00 05 02 00 00 00 0D
.

2、解决方案：

在网络中存在两个AC的情况，可以在MSG360上配置二次AC发现功能

1）二次AC发现功能作用：

二次发现AC功能用于向AP提供建立CAPWAP隧道的目的AC的IP地址。开启该功能后，AC发送的Discovery response报文中会携带CAPWAP Control IP Address消息元素，AP收到Discovery response报文后，将向消息元素中的IP地址发送Discovery request报文，达到二次发现AC的目的。

2）直接在AC1全局模式下配置：

system-view
wlan global-configuration 
control-address enable    #<==默认情况下二次发现AC功能处于关闭状态