Rockwell ArmorStratix 5700 series, Instructions Manual

Page: 314 / 548

314 Rockwell Automation Publication 1783-UM007F-EN-P - September 2016
Chapter 7 Configure Switch Features
Power over Ethernet (PoE) Switches and expansion modules with PoE ports are software-configurable and
provide these features:
• Support for IEEE 802.3af (PoE)-compliant devices.
• Support for IEEE 802.3at Type 2 (PoE+), which increases the available
power that can be drawn by powered devices from 15.4…30 W per port.
• Automatic detection and power budgeting. The switch maintains a
power budget, monitors and tracks requests for power, and grants power
only when it is available.
• Power to connected Cisco pre-standard and IEEE 802.3af-compliant
powered devices if the switch detects that there is no power on the
circuit.
• Support for Cisco Discovery Protocol (CDP) with power consumption.
CDP applies only when using switches with Cisco end devices. The
powered Cisco end device notifies the switch of the amount of power it
is consuming. The switch can supply or remove power from the PoE
port.
• Support for Cisco intelligent power management. A powered Cisco end
device and the switch negotiate through power-negotiation CDP
messages for an agreed power-consumption level. The negotiation
allows a high-powered device consuming more than 7 W to operate at
its highest power mode. The powered device first starts up in Low-
power mode, consumes less than 7 W, and negotiates to obtain enough
power to operate in High-power mode. The device changes to High-
power mode only when it receives confirmation from the switch.
Cisco intelligent power management is backward-compatible with CDP
with power consumption. The module responds according to the CDP
message that it receives. CDP is not supported on third-party powered
devices, so the module uses the IEEE classification to determine the
power usage of the device.
• (Stratix 5410 switches) Support for high and low priority PoE/PoE+
ports. When two power-supply modules are installed, the system has
enough power to support all ports as PoE/PoE+ ports. If one
power-supply module fails, the system drops power to the low priority
ports. Power to the high priority ports remains uninterrupted. If there is
not enough power for one supply to support all high priority ports,
ports are dropped by port number from highest to lowest port number.
PoE and PoE+ features are supported on switches and expansion modules with
PoE ports when a correct power supply is connected to the switch. For power
supply requirements, see
page 144 .