# PoE Control

### 1. Function Overview

PoE (Power over Ethernet) is a technology that supplies power using an Ethernet cable (category 5e or higher).
This product complies with IEEE 802.3at, which allows the product to supply power to Class 4 powered devices.
In IEEE 802.3at, terms called

- Power supply side (device that supplies power) PSE: Power Sourcing Equipment

- Power receiving side (device that receives power): PD: Powered Device

are defined.
This product uses Alternative A, which uses the signal lines (1, 2, 3, 6) of cables as the power supply method.

### 2. Definition of Terms Used

None

### 3. Function Details

#### 3.1. PoE power supply function enable/disable control

Ports that support PoE power supply of this product (hereinafter referred to as PoE ports) are as follows.

- SWX2210P-10G: ports 1 to 8

- SWX2210P-18G: ports 1 to 16

- SWX2210P-28G: ports 1 to 24

The power supply function of all the PoE ports of this product is enabled as the factory default.
However, the power supply function can also be disabled on the each port basis.
If the connected device is a normal Ethernet device, the power will not be supplied and the device will operate as a normal Ethernet port.

#### 3.2. Power supply class and maximum number of ports that can be powered simultaneously

This product is a power supply device that complies with the PoE standards. It can supply up to 30 W of power per port.
It automatically detects the connected PD, identifies its power class, and starts the power supply.
The power classes defined in IEEE 802.3at and the maximum number of ports that can be powered simultaneously are shown below.

Class | Power of device that receives power (MAX) | Power of device that supplies power | Maximum number of ports that can be powered simultaneously (Upper limit of PoE power supply)
--- | --- | --- | ---
SWX2210P-10G(124W) | SWX2210P-18G(247W) | SWX2210P-28G(370W)
0 | 13.0 W | 15.4 W | 8 | 16 | 24
1 | 3.84 W | 4.0 W | 8 | 16 | 24
2 | 6.49 W | 7.0 W | 8 | 16 | 24
3 | 13.0 W | 15.4 W | 8 | 16 | 24
4 | 25.5 W | 30.0 W | 4 (*) | 8 (*) | 12 (*)

- (*): Depending on the power consumption of the device that receives power, the simultaneous power supply beyond the number of ports listed can be performed.

#### 3.3. Guard band

A guard band is a margin set for the maximum power supply to prevent unexpected power outages.
If the available power supply amount reaches or falls below the guard band, power supply to a newly connected PD will be suppressed.
Setting this guard band value appropriately can prevent a newly connected PD from stopping the power supply to other PDs.
This product allows you to specify the guard band value in the range of 0 to 30 W. The default is 7 W.

#### 3.4. PoE power priority

This product allows you to specify the power supply priority order for each PoE port.
The priority is critical, high, and low in descending order. The default is low for all ports.
Among ports with the same priority setting, the smaller the port number, the higher the priority. The priority goes down in the port number order (1 → 2 → 3…​).
When an LLDP frame containing the Power via MDI TLV is received from a PD, the PoE port that received the LLDP frame operates with the power supply priority specified in the LLDP frame regardless of the power supply priority setting.

#### 3.5. PoE power supply actions

This product performs the following processes depending on the power consumption.

- When the power consumption of the entire system is about to exceed the upper limit of the PoE power supply.
  Power supply from PoE ports is stopped in the order from the lower priority to ensure that power consumption remains within the upper limit of PoE power supply.
  At this time, the PoE STATE LED of the port to which power supply has been stopped lights up orange, and the STATUS LED also lights up orange.
  In addition, “PortX.X over system power limit” is output to SYSLOG.

- If the available power supply amount reaches or falls below the guard band
  Power will continue to be supplied to PDs that are already being powered. However, power will not be supplied to a newly-connected PD regardless of its power supply priority.
  At this case, the PoE STATE LED of the port to which power was not supplied lights up orange, and the STATUS LED also lights up orange.

- When the power consumption of a specific PoE port has exceeded the upper limit of the PoE power supply per port
  Power supply to the corresponding PoE port will be stopped. Power supply to other PoE ports will continue.
  At this time, the PoE STATE LED of the port to which power supply has been stopped flashes orange, and the STATUS LED lights up orange.
  In addition, “PortX.X over load” is output to SYSLOG.

- If power consumption is other than the above (within normal range)
  Power supply to PDs will continue.
  At this time, the PoE STATE LED of the PoE port being powered lights up green.

In addition, the following processing will be performed if the PoE port status or the available power supply amount has changed.

- When power supply is started
  “PortX.X power on” is output to SYSLOG.
  The PoE STATE LED of the PoE port to which power supply has started lights up green.

- When power supply is stopped
  “PortX.X power off” is output to SYSLOG.
  The PoE STATE LED of the PoE port to which power supply has been stopped turns off.

- When the remaining available power supply amount reaches or falls below the guard band
  “guardband on” is output to SYSLOG.

- When the remaining available power supply amount recovers from a state at or below the guard band
  “guardband off” is output to SYSLOG.

#### 3.6. Power supply setting by LLDP

When the product receives an LLDP frame containing the Power via MDI TLV from a PD, it automatically changes the power supply action of the PoE port.
This function only works on PoE ports that can receive LLDP frames.
The Power Via MDI TLVs and the corresponding action to be changed are as shown below.

Power Via MDI TLV (IEEE802.3) | Action to be changed
--- | ---
Requested power priority | PoE power priority
PD requested power value | PoE port power allocation

### 4. Related Commands

Related commands are indicated below.
For command details, refer to the command reference.

Operations | Operating commands
--- | ---
Set the PoE power supply function for the entire system | power-inline enable
Set the PoE power supply function on an interface basis | power-inline enable
Set the description text for PoE ports | power-inline description
Set the PoE port priority | power-inline priority
Set a guard band | power-inline guardband
Show PoE power supply information | show power-inline

### 5. Examples of Command Execution

### 6. PoE Port Power Supply Settings

Specify the settings for the power supply function of port1.8.

    Yamaha(config)#power-inline enable (1)
    Yamaha(config)#interface port1.8
    Yamaha(config-if)#power-inline description AP1 (2)
    Yamaha(config-if)#power-inline priorty critical (3)
    Yamaha(config-if)#power-inline enable (4)
    Yamaha(config-if)#exit
    Yamaha(config)#exit

1 | Enable the PoE power supply function for the entire system. * Not required if the default settings are used
2 | Set AP1 as the PoE port description
3 | Set the PoE port priority to the highest
4 | Enable the PoE power supply function of the interface. * Not required if the default settings are used

### 7. Points of Caution

None

### 8. Related Documentation

None

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