The ECS4100-28P/52P/12PH switches can provide DC power to a wide range of connected devices, eliminating the need for an additional power source and cutting down on the amount of cables attached to each device. Once configured to supply power, an automatic detection process is initialized by the switch that is authenticated by a PoE signature from the connected device. Detection and authentication prevent damage to non-compliant devices (prior to IEEE 802.3af).
The switch’s power management enables individual port power to be controlled within the switch’s power budget. Port power can be automatically turned on and off for connected devices, and a per-port power priority can be set so that the switch never exceeds its power budget. When a device is connected to a switch port, its power requirements are detected by the switch before power is supplied. If the power required by a device exceeds the power budget of the port or the whole switch, power is not supplied.
Ports can be set to one of three power priority levels, critical, high, or low. To control the power supply within the switch’s budget, ports set at critical to high priority have power enabled in preference to those ports set at low priority. For example, when a device connected to a port is set to critical priority, the switch supplies the required power, if necessary by denying power to ports set for a lower priority during bootup.
Note: For more information on using the PoE provided by this switch refer to the Installation Guide.
Use the Administration > PoE > PSE (Configure Global) page to set the maximum PoE power budget for the switch (power available to all Gigabit Ethernet ports). If the power demand from devices connected to the switch exceeds the power budget, the switch uses port power priority settings to limit the supplied power.
Command Parameters
The power budget for the switch (i.e., power available to all switch ports). If devices connected to the switch require more power than the switch budget, the port power priority settings are used to control the supplied power.
Sets a power budget for the switch.
(ECS4100-28P: 50000-190000 milliwatts; Default: 190000 mW
ECS4100-52P: 50000-370000 milliwatts; Default: 370000 mW
ECS4100-12PH: 50000-180000 milliwatts; Default: 180000 mW)
Allows the switch to detect and provide power to powered devices that were designed prior to the IEEE 802.3af PoE standard. (Default: Disabled)
The switch automatically detects attached PoE devices by periodically transmitting test voltages that over the Gigabit Ethernet copper-media ports. When an IEEE 802.3af or 802.3at compatible device is plugged into one of these ports, the powered device reflects the test voltage back to the switch, which may then turn on the power to this device. When the compatibility mode is enabled, this switch can detect IEEE 802.3af or 802.3at compliant devices and the more recent 802.3af non-compliant devices that also reflect the test voltages back to the switch. It cannot detect other legacy devices that do not reflect back the test voltages.
For legacy devices to be supported by this switch, they must be able to accept power over the data pairs connected to the RJ-45 ports.
Sets the maximum power allocation mode based on PD (powered device) class or user configuration. (Default: Class)
Power allocation is based on device classification.
The IEEE standard does not define the maximum power of each PD class. The following table is an example from Microsem's PoE IC implementation.
Maximum PoE Based on PD Classification
PD Class | Maximum Power (Watts) |
---|---|
Class 0 (AF) | 16.1 |
Class 0 (AT) | 33.6 |
Class 1 | 4.2 |
Class 2 | 7.3 |
Class 3 | 16.1 |
Class 4 | 33.6 |
For legacy devices to be supported by this switch, they must be able to accept power over the data pairs connected to the RJ-45 ports.
Power allocation is based on user configuration as defined in the PoE Maximum Allocation Power setting on this page or as defined on the Administration > PoE > PSE (Configure Interface) page.
Use the Administration > PoE > PSE page to set the maximum power provided to a port.
Command Usage
This switch supports both the IEEE 802.3af PoE and IEEE 802.3at-2009 PoE Plus standards. To ensure that the correct power is supplied to powered devices (PD) compliant with these standards, the first detection pulse from the switch is based on 802.3af to which the 802.3af PDs will respond normally. It then sends a second PoE Plus pulse that causes an 802.3at PD to respond as a Class 4 device and draw Class 4 current. Afterwards, the switch exchanges information with the PD such as duty-cycle, peak and average power needs.
All the RJ-45 ports support both the IEEE 802.3af and IEEE 802.3at standards.
For the ECS4100-28P, the total PoE power delivered by all ports cannot exceed the maximum power budget of 190W.
For the ECS4100-52P, the total PoE power delivered by all ports cannot exceed the maximum power budget of 370W.
For the ECS4100-12PH, the total PoE power delivered by all ports cannot exceed the maximum power budget of 180W.
The number of ports which can supply maximum power simultaneously to connected devices is listed in the following table. In this table, EPS refers to the optional external power supply.
Maximum Number of Ports Providing Simultaneous Power
Switch | 30W (802.3at) | 15.4W (802.3af) | 7.5W (802.3af) |
---|---|---|---|
ECS2000-10PE | 2 | 4 | 8 |
ECS2000-10P | 4 | 8 | 8 |
ECS2000-28P | 6 | 12 | 24 |
ECS2000-28PP (without EPS) | 12 | 24 | 24 |
ECS2000-28PP (with EPS) | 24 | 24 | 24 |
If a device is connected to a switch port and the switch detects that it requires more than the power budget set for the port or to the overall switch, no power is supplied to the device (i.e., port power remains off).
If the power demand from devices connected to all switch ports exceeds the power budget set for the switch, the port power priority settings are used to control the supplied power. For example:
If a device is connected to a low-priority port and causes the switch to exceed its budget, power to this port is not turned on.
If a device is connected to a critical or high-priority port and would cause the switch to exceed its power budget as determined during bootup, power is provided to the port only if the switch can drop power to one or more lower-priority ports and thereby remain within its overall budget.
If a device is connected to a port after the switch has finished booting up and would cause the switch to exceed its budget, power will not be provided to that port regardless of its priority setting.
If priority is not set for any ports, and there is not sufficient power to supply all of the ports, port priority defaults to Port 1, Port 2, Port 3 ... Port 24/48, with available power being supplied in that sequence.
If priority is not set for any ports, and PoE consumption exceeds the maximum power provided by the switch, power is shut down in the reverse sequence, starting from Port 24/48.
Command Parameters
The port number on the switch.
Enables PoE power on a port. Power is automatically supplied when a device is detected on a port, providing that the power demanded does not exceed the switch or port power budget. (Default: Enabled)
Shows whether or not PoE power is being supplied to a port. Note that if power is turned off due to an overload, administative status will still display enabled.
Name of a time range. If a time range is set, then PoE will be provided to an interface during the specified period.
Indicates if a time range has been applied to an interface, and whether it is currently active or inactive.
Shows the maximum power allocation class as defined by the Maximum Allocation Mode setting on the PoE>PSE (Configure Global) page. Class information is shown only when Mode = on.
Sets the power priority for a port. (Options: Low, High, or Critical; Default: Low)
Sets the power budget for a port. (Range: 3000- 34200 milliwatts; Default: 34200 milliwatts)
Current power consumption on a port.