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Determining and Setting Priority for Switches Connected to an EX Series RPS

A Redundant Power System (RPS) provides backup power according to the RPS priority configured on the standalone EX Series switches or Virtual Chassis member switches connected to it. If all switches connected to the RPS are set to the default priority of 1, the priority is determined on the basis of the RPS port to which they are connected, with higher port numbers having the higher priorities.

The number of switches for which an RPS can provide backup power depends on whether the switches provide power over Ethernet (PoE).

  • PoE: A fully loaded RPS provides backup power to a maximum of three switches that are enabled for PoE—the result in this case is one switch powered per power supply. If more than three PoE-enabled switches are connected to the RPS and the RPS is already providing backup power to three switches when another switch's power supply fails, the RPS detects this and re-allots backup power as required. It would then stop providing backup power to a low-priority switch to provide backup power to a higher-priority switch.

  • Non-PoE: If you changed the RPS power setting to non-PoE with the command request redundant-power-system multi-backup, your RPS is configured to provide back up power to as many as six non-PoE switches on a fully loaded RPS. Each power supply can support two switches when the switches do not need enough power for PoE.


Before an RPS can back up a switch connected to it, the switch’s RPS status must be ARMED. There are two ways to determine whether a switch’s RPS status is ARMED—either check that the corresponding port LED on the RPS is lit and on steady or issue this command from the switch’s CLI: show chassis redundant-power-system.

This topic describes how to determine and set the power priority for a switch connected to an RPS.

Using RPS Default Configuration

No configuration is required on an RPS if you:

  • Plan to back up as many as six non-PoE switches

  • Back up three PoE switches with three RPS power supplies

  • Back up four or more PoE switches with RPS three power supplies and let the RPS port to which the switch is connected determine the priority

By default, an RPS assigns priority to switches on the basis of their switch connector port location, with the with higher port numbers having the higher priorities. By default, all switches are themselves configured with the same RPS priority (priority 1, the lowest), which is why priority is derived from the RPS connector port numbers.

Setting the EX Series RPS Priority for a Switch (CLI)

Each switch connected to RPS has an RPS priority value—that priority value determines which PoE switches receive power first from the RPS. By default, all switches are configured for priority 1 so priority is then determined by switch connector port location, left (lowest) to right (highest).

You can change the priority of a switch to 0 (off), or 1 (lowest) through 6 (highest) from the switch itself—this configuration takes precedence over switch connector port location.

To set or change the priority for a switch that does not support Virtual Chassis:

To set or change the priority for a switch that supports Virtual Chassis:

Where member is 0 for a switch that has never been configured in a Virtual Chassis.