Wireless APs cannot find a controller

At first, the default configuration is used, the thin AP does not have any configuration, so that the thin AP connected to the network will be on their own to find the controller, but sometimes can not find
Later, the following document, directly in the thin AP to specify the controller's IP address, so he went directly to the designated IP to do certification, and will not go flooding to find the controller
The problem will be solved.
The thin AP is configured as follows: Ap#capwap AP IP address <ip address> <subnet mask>
Ap#capwap AP IP default-gateway <IP-address>
Ap#capwap AP Controller IP address <IP-address>
Ap#capwap AP hostname <name> Copy Code