Saving power – Brocade Communications Systems Brocate Ethernet Access Switch 6910 User Manual
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Brocade 6910 Ethernet Access Switch Configuration Guide
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Saving Power
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Saving Power
Use the Interface > Green Ethernet page to enable power savings mode on the selected port.
CLI References
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Command Usage
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IEEE 802.3 defines the Ethernet standard and subsequent power requirements based on
cable connections operating at 100 meters. Enabling power saving mode can reduce power
used for cable lengths of 60 meters or less, with more significant reduction for cables of 20
meters or less, and continue to ensure signal integrity.
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The power-saving methods provided by this switch include:
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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 (enters 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.
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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 cable
length is shorter, power consumption can be reduced since signal attenuation is
proportional to cable length. When power-savings mode is enabled, the switch analyzes
cable length to determine whether or not it can reduce the signal amplitude used on a
particular link.
NOTE
Power savings can only be implemented on Gigabit Ethernet ports when using twisted-pair cabling.
Power-savings mode on a active link only works when connection speed is 1 Gbps, and line length
is less than 60 meters.
Parameters
These parameters are displayed:
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Port – Power saving mode only applies to the Gigabit Ethernet ports using copper media.
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Power Saving Status – Adjusts the power provided to ports based on the length of the cable
used to connect to other devices. Only sufficient power is used to maintain connection
requirements. (Default: Enabled on Gigabit Ethernet RJ-45 ports)