PD Disconnect Precedence

After a PD is discovered and powered on a Summit switch, the actual power drain is continuously measured.

If the usage for power by PDs is within the guard band, the system begins denying power to PDs.

You can configure the switch to handle a request for power that exceeds the power budget situation in one of two ways, called the disconnect precedence:
  • Disconnect PDs according to the configured PoE port priority for each PD.
  • Deny power to the next PD requesting power, regardless of that port‘s PoE priority.

The default value is deny-port. So, if you do not change the default value and the switch‘s or slot‘s power is exceeded, the next PD requesting power is not connected (even if that port has a higher configured PoE port priority than those ports already receiving power). When you configure the deny-port value, the switch disregards the configured PoE port priority and port numbering.

When the switch is configured for lowest-priority mode, PDs are denied power based on the individual port‘s configured PoE priority. If the next PD requesting power is of a higher configured PoE priority than an already powered port, the lower-priority port is disconnected and the higher-priority port is powered.