The behavior of which packet type can be controlled by selecting unicast mode or flood mode in a bridge domain?

ARP (Address Resolution Protocol) packets are broadcast by nature and are flooded within a bridge domain, and their behavior is not typically controlled by a unicast or flood mode setting for unknown unicast.

Bridge domains provide a setting to control how unknown unicast frames are handled: they can be either flooded across all ports within the bridge domain (flood mode) or dropped, or directed to a specific destination (unicast mode).

LLDP (Link Layer Discovery Protocol) packets are multicast and are handled differently from unknown unicast, and their forwarding behavior is not governed by the unicast/flood mode setting of a bridge domain.

CDP (Cisco Discovery Protocol) packets are multicast and are not considered unknown unicast, therefore their forwarding is not controlled by the unicast/flood mode setting in a bridge domain.