Monitoring, Management & Location Tracking

‘Show poe’ can be used to see CLI output  for the POE ports on the controller supplying POE for directly-connected AP’s.

This is from an 800 controller:

(WC0490) #show poe

PoE Status
----------
Port    Status  Voltage(mV)  Current(mA)  Power (mW)
----    ------  -----------  -----------  ----------
FE1/0   Off     N/A          N/A          N/A
FE1/1   Off     N/A          N/A          N/A
FE1/2   On      48030        119          5739
FE1/3   On      47870        124          5873
FE1/4   Off     N/A          N/A          N/A
FE1/5   Off     N/A          N/A          N/A
FE1/6   On      47774        69           3310
FE1/7   On      47550        94           5513
GE 1/8  Off     N/A          N/A          N/A


Total Power Usage: 20435 (mW)


What the Output Signifies

What does the output mean?  Use the formula:  

Power (W) = Volts (V) * Current (A)

So…

FE1/2   On      48030        119          5739

…means POE voltage measured at output of the controller for this port is 48.030Volts, current sourced is 119mA, for the total of wattage drawn by the AP from this port is 5.739Watt.

Output like the following…

FE1/6   On      47774        69           3310

…looks like the radio is not on yet, 3.3Watt is quite low.  This can occur while the AP is powering up and before the radios have been enabled, ie., before the configuration has been pushed to the AP.  ~4.5W or higher is normal.  If output like the above is seen for a sustained period of time and if the AP is configured to operate as an AP, then some troubleshooting should be done to determine the source of the low power output.

Typical draw for the AP65 is ~6W, and for the AP70 is ~8W (radios active).

For the total output for all ports, the 800 has 100Watt power supply, so for 8 ports, each 10W, there should be sufficient power for 8 AP’s.