Overview of power-saving features

There are several power-saving features that can be configured for the indicated switches and modules. The power-saving features include:

  • Turn slot power on or off

  • Turn LED power on or off

  • Turn slot auto low-power mode on or off

  • Use LLDP for Energy-Efficient-Ethernet

Slot power

The savepower module option shuts down the slot power for the specified modules in the order specified in the command. The ports on these modules no longer pass traffic. Any management traffic (SNMP, SSH, Telnet) that passes through these modules is interrupted. It can take up to two minutes to power down all the specified modules. Check the Event Log to see the current status of the module power down. This command applies to PoE/PoE+ modules as well as non-PoE/PoE+ modules.

LED power

The savepower LED option provides the ability to turn off specified slot LEDs or all LEDs. You can also configure a timer for turning off the chassis LEDs or the specified slot LEDs. There is one system-wide timer; all the selected slots will have the chassis LEDs turned off for the same amount of time.

When the timer option is configured, a timer for turning off the chassis LEDs or configured slot LEDs. The LEDs are turned off for the configured time period and duration.


Specifies the date and time to start the timer.


Instantaneously turns off the LEDs. The configured timer is canceled and all the configured modules go into power-saving mode immediately.


duration [HH:]MM: The amount of time the LEDs remain turned off. (Optional)If the duration value is zero, when the timer starts, the LEDs are turned off indefinitely until the timer is canceled or the command is overridden with another command.Default: 0 (zero)


recur: (Optional) If specified, the LEDs are turned off on a daily basis at the configured time. The recur option is ignored if the duration is configured as zero.Default: disabled.

A new command overrides the previous command, regardless of the current state. For example, if a timer is active and new command is given, the currently running timer is canceled and the new timer is scheduled.

Slot auto low-power mode

The auto low-power mode option puts the slots into auto low-power mode if they are not linked. If a particular slot is specified, only that slot goes into auto low-power mode. Specifying savepower port-low-pwr all puts all the slots into auto low-power mode.

The ports in low-power mode periodically monitor to determine if the link has become active. If a LAN cable is connected to one of the ports, that port will come out of the low-power mode state after approximately 2 seconds (the monitor period) and enter into normal power mode. The remaining ports continue to be in low-power mode.


Energy-efficient-ethernet (EEE) follows the 802.3az standard, which provides support for a system to operate in low-power idle mode during low-link use. This allows both sides of a link to disable or turn off a portion of the system's transmit/receive circuitry, saving power. When traffic is ready for transmission, the interface sends a "wake-up" message to the link partner to prepare to receive the traffic. The circuitry is returned to "normal" mode. Both sides of the link must be EEE-capable to support the power-saving idle mode.

Layer 2 (data link layer) EEE capability is a feature that allows fine-tuning for EEE that uses LLDP TLVs for the negotiation of physical link partners' wake-up time values. An EEE-capable port notifies its link partner about the EEE capabilities supported. The ports then negotiate how to best optimize energy efficiency.