Port Management
Green Ethernet
Cisco Small Business SG200 Series 8-port Smart Switches Administration Guide
90
5
Green Ethernet
On each gigabit Ethernet copper port the switch provides a Green Ethernet power
saving feature called Energy Detect Mode. It reduces chip power by forcing a port
PHY into a low-power mode when the signal from a copper link partner is not
present. (PHY is an abbreviation for the physical layer of the OSI model.)
When the Energy Detect is enabled and energy on the line is lost, the switch
automatically enters the low-power mode. It resumes normal operation when
energy is detected. When the port PHY is in low-power mode, the PHY wakes up
after a period of time, and sends link pulses to monitor for energy from the link
partner. If energy is detected while the port is in wake-up mode, the switch returns
the port to normal operation. When the wake-up period expires, the port returns to
low-power mode.
When Short Reach Auto is enabled, a cable test is performed when a link comes
up. If the length of the cable is less than 10 meters, the PHY can be put into low-
power mode so that only enough power is used to support a short cable. When
the link goes down, low-power mode is disabled.
The switch also supports Short Reach Force, where the port is administratively
forced into low-power mode.
Wnen enabled, the Green Ethernet features function whether the port has
autonegotiation enabled or disabled.
Configuring Green Ethernet Properties
Use the
Green Ethernet Properties
page to enable Green Ethernet functionality
globally. The global settings are applied to all ports.
NOTE
You can override the global settings by configuring these features on individual
ports (see
Configuring Green Ethernet Port Settings
); however, changes that you
subsequently make to the global settings override any individual port configuration.
To configure global Green Ethernet properties:
STEP 1
Click
Port Management
>
Green Ethernet
>
Properties
in the navigation window.
By default, Energy Detect mode and Short Reach Auto mode are enabled globally
and on all ports.
