2-event classification is a method that allows the switch’s power sourcing equipment (PSE) to signal its ability to provide higher power (up to 30W) to a powered device. With 2-event classification, when a class 4 powered device is detected, Cisco IOS allocates 30W of power without requiring CDP (Cisco Discovery Protocol) or LLDP (Link Layer Discovery Protocol) negotiation. This means that even before the network link becomes operational, the Class 4 powered device can receive 30W of power.