Cfc Power Management; Card Power Management - Allied Telesis SwitchBlade x3100 Series Manual

Introduction

CFC Power Management

continue to even if the port is administratively disabled or if the PD disables its Ethernet. This allows the port
or the device to disable traffic without shutting down power.
3.2.5 CFC Power Management
The CFC is responsible for setting the maximum power allowed by each PoE card.
It does this by going through the ports on each slot (starting with the ports on slot 0) and summing the
requested usage for all enabled ports that have detected a PD. The requested usage for a port is the user
defined power limit (if set) or the class's power limit (if user power limit is not set). The first pass allocates
power for critical priority ports, followed by high priority ports, and then low priority ports (if any power
remains). Any power left over after this allocation is divided evenly amongst the slots (so that they can more
quickly respond to detected PDs before the CFC has time to respond). The CFC's power allocation algorithm
is performed each time a PD is detected or removed (or a port is enabled/disabled).
Each card also has a minimum power limit of 37W. The CFC ensures that any card with enabled PoE ports must
get at least 37W regardless of requested power. If all ports have PoE disabled, then the card will not be allo-
cated power.
The CFC will alarm the card or the system if the requested power need was not able to be met. At this point
there may or may not be alarms on the interfaces (the actual power draw may not have exceeded the alloca-
tion), but the user is warned that there is not enough allocated power to meet the requested need.
The CFC also calculates the power allocation for the cases where any currently installed PoE PSU is removed
and sends down those card power limits as well so that the GE24POE card can quickly reallocate power in the
case of PSU removal.

3.2.6 Card Power Management

The GE24POE card is responsible for limiting each port to its port power limit (which is the class limit if no
user limit is set) as well as taking the total card power (determined by the CFC) and allocating it to each of the
ports based on priority. The difference here is that (due to hardware limitations) instead of comparing the sum
of each port's class power to the card limit, it uses instead the actual current power usage of the ports. The
impact of this is that some ports may be receiving power when the CFC's algorithm would have assumed they
would not be. These ports would be the first to lose power if higher priority ports on the card began to need
more power.
3.2.7 LEDs
The faceplate for the GE24POE card has two light-emitting diodes (LEDs) per port. The top left LED indicates
traffic status while the top right LED is reserved for PoE status. The following table shows the meanings for this
LED.
3-4
Software Reference for SwitchBlade x3100 Series Switches (Power over Ethernet (PoE))