Information About Neighbor Discovery Protocol Mode
In Cisco Catalyst 9124AX outdoor Access Points, the Neighbor Discovery Protocol (NDP) packets are transmitted either ON-channel on the serving radio, or OFF-channel on the RF ASIC conventional radio. The controller has a knob to select the NDP mode for Cisco Catalyst 9124AX outdoor APs based on the deployment requirements. In Cisco IOS XE Bengaluru 17.5.1, Cisco Catalyst 9124AX outdoor APs support both ON-Channel and OFF-Channel NDP mode.
The Cisco Catalyst 9124AX outdoor AP advertises the following NDP mode capabilities while joining the controller:
ON-Channel (Serving channel)
OFF-Channel (RF ASIC radio)
Both (Serving channel and RF ASIC radio)
The supported values for NDP mode are AUTO and OFF-Channel. By default, the NDP mode is set to AUTO.
If the configured NDP mode is AUTO, the AP determines which NDP mode is to be used. The Cisco Catalyst 9124AX outdoor AP uses ON-Channel when the controller is configured for AUTO NDP mode. If the NDP mode that is configured is OFF-Channel, the AP uses OFF-Channel for NDP mode.
You must configure the controller NDP mode to OFF-channel in order to support brownfield deployment. A brownfield deployment refers to the mixed deployment of Cisco Catalyst 9124AX with other APs that do not support RF ASIC conventional radio. APs that support RF ASIC conventional radio are Cisco Catalyst 9120 Series Access Points, Cisco Catalyst 9130 Series Access Points, and Cisco Catalyst 9124 Series Access Points.