CLI Reference Guide-R07

Chapter 11 | Interface Commands
Power Savings
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Power Savings
power-save This command enables power savings mode on the specified port. Use the no form
to disable this feature.
Syntax
[no] power-save
Default Setting
Enabled
Command Mode
Interface Configuration (Ethernet ports 1-22/48)
Command Usage
◆ Power saving mode only applies to the Gigabit Ethernet ports using copper
media.
◆ Power savings can be enabled on Gigabit Ethernet RJ-45 ports.
◆ The power-saving methods provided by this switch include:
■
Power saving when there is no link partner:
Under normal operation, the switch continuously auto-negotiates to find a
link partner, keeping the MAC interface powered up even if no link
connection exists. When using power-savings mode, the switch checks for
energy on the circuit to determine if there is a link partner. If none is
detected, the switch automatically turns off the transmitter, and most of
the receive circuitry (entering Sleep Mode). In this mode, the low-power
energy-detection circuit continuously checks for energy on the cable. If
none is detected, the MAC interface is also powered down to save
additional energy. If energy is detected, the switch immediately turns on
both the transmitter and receiver functions, and powers up the MAC
interface.
■
Power saving when there is a link partner:
Traditional Ethernet connections typically operate with enough power to
support at least 100 meters of cable even though average network cable
length is shorter. When power-savings mode is enabled, the switch
determines whether or not it can reduce the signal amplitude used on a
particular link.
◆ When the power-save command is enabled and traffic is reduced there is a
reduction in power. For example, factory hardware component testing has
shown significant power reduction >10%-45%
9
are realized when 1000M
Ethernet ports operate at slower rates from 300 to 0 Mbps.
9. The percentage reduction is for the switch hardware interface internal component only.