refer to the switch relese note once, also refer the below link which explains the Cisco Switch's power management to the device in case both CDP and LLDP are disabled.
Maximum Power Allocation (Cutoff Power) on a PoE Port
When power policing is enabled, the switch determines the cutoff power on the PoE port in this order:
1.
Manually when you set the user-defined power level that the switch budgets for the port by using thepower inline consumption default wattage global or interface configuration command
2. Manually when you set the user-defined power level that limits the power allowed on the port by using the power inline auto max max-wattage or the power inline static max max-wattage interface configuration command
3. Automatically when the switch sets the power usage of the device by using CDP power negotiation or by the IEEE classification and LLDP power negotiation.
Use the first or second method in the previous list to manually configure the cutoff-power value by entering the power inline consumption default wattage or the power inline [ auto | static max ] max-wattagecommand. If you do not manually configure the cutoff-power value, the switch automatically determines the value by using CDP power negotiation. If the switch cannot determine the value by using one of these methods, it uses the default value of 15.4 W.
On a switch with PoE+, if you do not manually configure the cutoff-power value, the switch automatically determines it by using CDP power negotiation or the device IEEE classification and LLDP power negotiation. If CDP or LLDP are not enabled, the default value of 30 W is applied. However without CDP or LLDP, the switch does not allow devices to consume more than 15.4 W of power because values from 15400 to 30000 mW are only allocated based on CDP or LLDP requests. If a powered device consumes more than 15.4 W without CDP or LLDP negotiation, the device might be in violation of the maximum current ( Imax) limitation and might experience an Icut fault for drawing more current than the maximum. The port remains in the fault state for a time before attempting to power on again. If the port continuously draws more than 15.4 W, the cycle repeats.
Note When a powered device connected to a PoE+ port restarts and sends a CDP or LLDP packet with a power TLV, the switch locks to the power-negotiation protocol of that first packet and does not respond to power requests from the other protocol. For example, if the switch is locked to CDP, it does not provide power to devices that send LLDP requests. If CDP is disabled after the switch has locked on it, the switch does not respond to LLDP power requests and can no longer power on any accessories. In this case, you should restart the powered device.
