PoE - jibingl/CCNA-CCNP GitHub Wiki
Power over Ethernet
Name | Standard | Walts | Powered Wire Pairs |
---|---|---|---|
Cisco Inline Power (ILP) | not standard | 7 | 2 |
PoE (Type 1) | 802.3af | 15 | 2 |
PoE+ (Type 2) | 802.3at | 30 | 2 |
UPoE (Type 3) | 802.3bt | 60 | 4 |
UPoE+ (Type 4) | 802.3bt | 100 | 4 |
provide-power(DC)
PD(Phone)-------ethernet---.
- \ power-cable(AC)
PD(IPcam)-------ethernet----- [=]-----------------------[outlet]
- / PSE
PD(AP)----------ethernet---`
(Powered Device) (Power Sourcing Equipment)
PoE has a process to determine if a connected device needs power, and how much power it needs:
- When a device connects to a PoE-enabled port, the PSE (normally switch) sends low power signals, monitors the response, and determines how much power the PD needs.
- If the device needs power, the PSE supplies the power to allow the PD to boot.
- The PSE continues to monitor the PD and supply the required amount of power (but not too much).
Power Policing can be configured to prevent a PD from taking too much power.
power inline police
configures power policing with the default settings: disable the port and send a Syslog message if a PD draws too much power.power inline police action err-disable
is equivalent to above.power inline police action log
doesn't shut down the interface instead to restart the interface and send a Syslog message.