拓扑：

　　AP2602I----4500-----Nexus5000-------UCSC240--vWLC

　　4500上配置

　　ip dhcp pool VLAN141-Test

　　network 10.8.141.0 255.255.255.0

　　default-router 10.8.141.254

　　option 43 ascii 10.8.141.1

　　dns-server 202.106.0.20 8.8.8.8

　　网关都在4500上

　　nexus5000上联下联均是trunk

　　把AP换成PC的话，拿到的IP去ping vWLC:10.8.141.1 不通，但反过来vWLC ping PC 可通，然后双向互ping ，通!

　　vWLC sysinfo信息：

　　(Cisco Controller) >show sysinfo

　　Manufacturer's Name.............................. Cisco Systems Inc.

　　Product Name..................................... Cisco Controller

　　Product Version.................................. 8.0.110.0

　　RTOS Version..................................... 8.0.110.0

　　Bootloader Version............................... 8.0.110.0

　　Emergency Image Version.......................... 8.0.110.0

　　Build Type....................................... DATA + WPS

　　System Name...................................... Chenbo

　　System Location..................................

　　System Contact...................................

　　System ObjectID.................................. 1.3.6.1.4.1.9.1.1631

　　IP Address....................................... 10.8.141.1

　　在AP上就反复看到如下信息：

　　Not in Bound state.

　　*Mar 25 07:48:21.463: %CAPWAP-3-DHCP_RENEW: Could not discover WLC. Either IP address is not assigned or assigned IP is wrong. Renewing DHCP IP.

　　*Mar 25 07:48:26.587: %DHCP-6-ADDRESS_ASSIGN: Interface BVI1 assigned DHCP address 10.8.141.181, mask 255.255.255.0, hostname AP7cad.7440.5a41

　　Translating "CISCO-CAPWAP-CONTROLLER"...domain server (255.255.255.255)

　　Not in Bound state.

　　*Mar 25 07:49:35.963: %CAPWAP-3-DHCP_RENEW: Could not discover WLC. Either IP address is not assigned or assigned IP is wrong. Renewing DHCP IP.

　　*Mar 25 07:49:41.087: %DHCP-6-ADDRESS_ASSIGN: Interface BVI1 assigned DHCP address 10.8.141.182, mask 255.255.255.0, hostname AP7cad.7440.5a41

　　Translating "CISCO-CAPWAP-CONTROLLER"...domain server (255.255.255.255)

　　参考答案：

　　AP 通过DHCP拿到地址以后，ping 10.8.141.1， 如果可达，再在AP侧手动指一下controller, 告诉AP注册到哪个controller.

　　命令如下：

　　AP0022.9090.e859#capwap ap controller ip address 10.8.141.1