Overview of Energy-Saving Management
Purpose
The energy-saving management function reduces power consumption.
As network scales enlarge, power consumption increases, which increases operation costs. Energy saving is becoming a major concern in network construction.
Energy-Saving Management Features Supported by the Device
The device supports energy-saving features including intelligent fan speed adjustment, Energy Efficient Ethernet (EEE), and automatic laser shutdown (ALS).
Intelligent fan speed adjustment
Intelligent fan speed adjustment enables the device to run at normal temperatures and reduces power consumption and noise. It monitors the temperature of key components and increases the fan speed if a sensitive component overheats. When the temperature falls back to its normal range, the fan speed is decreased.
ALS
ALS protects operators against laser injury and saves energy. It controls the pulse of the laser of an optical module by detecting the Loss of Signal (LOS) on an optical interface.
Without ALS, if an optical fiber link fails, data communication is interrupted but the optical interface and the laser of an optical module are still enabled. Energy is wasted and eyes of operators may be hurt. With ALS, the LOS is detected and the laser is disabled. When the faulty optical fiber link is recovered, the system detects that the LOS of the optical interface is cleared and enables the laser again.
EEE
EEE reduces system power consumption by dynamically adjusting the electrical interface power according to network traffic volume.
Without EEE, the system provides power to every interface, resulting in idle interfaces using as much power as used interfaces. Using EEE, power to idle interfaces is reduced and then restored when the interface becomes in use.
Port dormancy
In port dormancy mode, the physical layer (PHY) chip on an electrical interface enters the low energy consumption mode to reduce power consumption. When the interface is not connected, major data transmission channels of the chip enter the dormancy state to save energy. When the interface is connected and traffic on the cable is detected, the PHY chip restores to its normal working state.
Device dormancy
In the dormant state (also known as sleep mode), devices enter the low power consumption mode and all chips except the CPU enter the power saving mode. On an enterprise network, devices may not be required at all time. You can make these devices dormant to save power. A time range or certain criteria can be set to awaken the devices. After awakened, devices enter to the normal working state.
Only the S5720-28P-SI-AC, S5720-28X-SI-AC, S5720-28X-SI-DC, S5720-52P-SI-AC, S5720-52X-SI-DC, and S5720-52X-SI-AC in the S5720-SI series, and the S5735-S, S5735-S-I, S5735S-S, S5735-L, S5735S-L, S5735S-L-M, and S5720S-SI series switches support the sleep mode.
After a device enters the sleep mode, services on the device are interrupted. If the device is located in the middle of a ring or tree network, you are advised not to change the device to sleep mode.
If a device has fans, the fans will stop running when the device enters the sleep mode. Fans in the following switches, however, will not stop running when the switches enter the sleep mode: S5735-S, S5735-S-I, S5735S-S, S5735-L, S5735S-L, and S5735S-L-M series, S5720-52P-SI-AC and S5720-52X-SI-AC, S5720-52X-SI-DC in the S5720-SI series, S5720S-52P-SI-AC, S5720S-52X-SI-DC, and S5720S-52X-SI-AC in the S5720S-SI series.
A stack does not support the sleep mode.
When the device is in sleep mode, you can connect a network cable to an awakening port to awaken the device, regardless of whether the network cable connects to a remote device.
After the computer connected to the awakening port is powered off, the network adapter installed on the computer must have no power. If the network adapter has power, the device cannot enter the sleep mode or is awakened from the sleep mode.
Energy-saving modes
The device can run in the following energy-saving modes:-
Factory mode and default power saving mode.
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Components not in use are shut down or switched to the sleep mode when no services are configured or users are not online.
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Power consumption is dynamically adjusted for running services, and components not in use are shut down or switched to the sleep mode according to service requirements.
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The device enters the low power consumption mode when it does not need to provide PoE power to PDs and shuts down all the interfaces except GE0/0/13 and GE0/0/14.
The ALS, EEE, and port dormancy functions are disabled in standard mode by default. However, the port dormancy function is enabled by default on the ES5D21X02T01 electrical sub-card supported by the S5720-EI, the ES5D21X08T00 electrical sub-card supported by the S5730-HI, S5731-H, and S5731S-H, and cannot be disabled.
- The ALS, EEE, and port dormancy functions are enabled by default in basic or deep mode.
- The deep mode adds the device dormancy function based on functions of the basic mode.
- Only the S5720-16X-PWH-LI supports the standby mode. The interfaces that have been shut down in standby mode cannot be enabled manually using a command. To enable these interfaces manually, ensure that the switch exits the standby mode.
- Before entering the standby mode, the system forcibly saves the configuration to the configuration file that is being used by the device.
- The configuration restoration function is not configured in the standby mode. That is, after the device restarts, the currently configured standby mode of an interface is automatically restored to the default standard mode.
- On the S5720-16X-PWH-LI XGE0/0/1 and XGE0/0/2, installing optical modules and configuring the standby mode are mutually exclusive. That is, the two interfaces cannot have the standby mode configured after they have optical modules installed. When they work in standby mode, installing optical modules into them will restore them to the default standard mode or may even restart the device.
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