Combined Power allows switches with two power supply modules to draw power from both the modules simultaneously.
Traditionally, switches with two power supply modules are designed to use them in redundant mode. In such a configuration, only one of the modules provides power to the switch at any time, while the second module remains on stand-by, ready to sustain the supply of power if the first module was to fail.
With Combined Power, the second power supply module, will also provide power for PoE up to its maximum rated limit, while still acting as a stand-by power supply for the switch control system. In the event of a failure on the primary power supply module, the secondary module will ensure power to the switch remains uninterrupted while the power provisioning for PoE will be modified as criteria explained in the section Power Budgeting with Combined Power.
Combined Power Supported Models: MS350, MS355 and MS390 Series. MS390 switches always operate in Combined Power mode.
Configuring Combined Power
To configure the power mode, navigate to Switch > Configure > Switch Settings. Here you can choose between Redundant power and Combined power, as the 'default power supply setting.' for the switches in your network. If there are switches in your network which should not follow the default power settings, you can map those switches to either of the power modes using custom lists, from the 'power supply settings exceptions,' section.
This option is only available when the switch has two power supply modules inserted and powered. This feature is available only for Switches running firmware MS 11.0 and above.
Power Budgeting with Combined Power
Combined Power Budget
Note: The switches will budget based on the PoE device classification, the budget is allowed to exceed available power as it's used to gauge overall power that might be consumed on the switch. Devices will continue to be powered until the consumption goes over the available amount of power or one of the power supply module fails. In this case the lowest port numbers take precedence and power will be pulled from the highest ports thus denying them power