An AP can obtain an IP address in any of the following modes:
Static mode: A user logs in to the AP and configures its IP address.
In static mode, if the AP is on the same network segment as the AC, specifying the IP address of the AC is not mandatory. However, if the AP and AC are on different network segments, you must specify the IP address of the AC.
DHCP mode: The AP serves as a DHCP client and requests an IP address from a DHCP server.
If the AP is on the same network segment as the AC, the AP can discover the AC in broadcast mode. You do not need to configure the Option 43 field or obtain the IP address of the AC from the DNS server. If the AP is configured to notify the AC of its IP address through Option 43 or DNS, the AP sends a Discovery Request unicast packet to the AC with the specified IP address for discovery. If the AP does not receive any response after sending 10 Discovery Request unicast packets, it broadcasts Discovery Request packets to discover other ACs on the same network segment as the AC.
If the AC and AP are on different network segments, you must configure Option 43 or DNS to specify the AC's IP address so that the AP can discover the AC and go online successfully.
Stateless address autoconfiguration (SLAAC) mode: APs obtain IP addresses in SLAAC mode. Only IPv6 addresses can be obtained.
