3-1.7 Eee - Manufacture Technology GEFXL2-CSW28KX User Manual

3-1.7 EEE

The section which allows the user to inspect and configure the current EEE port settings.
EEE is a power saving option that reduces the power usage when there is very low traffic
utilization (or no traffic).
EEE works by powering down circuits when there is no traffic. When a port gets data to be
transmitted all circuits are powered up. The time it takes to power up the circuits is named
wakeup time. The default wakeup time is 17 us for 1Gbit links and 30 us for other link speeds.
EEE devices must agree upon the value of the wakeup time in order to make sure that both
the receiving and transmitting device has all circuits powered up when traffic is transmitted.
The devices can exchange information about the devices wakeup time using the LLDP
protocol.
For maximizing the power saving, the circuit isn't started at once transmit data are ready for a
port, but is instead queued until 3000 bytes of data are ready to be transmitted. For not
introducing a large delay in case that data less then 3000 bytes shall be transmitted, data are
always transmitted after 48 us, giving a maximum latency of 48 us + the wakeup time.
If desired it is possible to minimize the latency for specific frames, by mapping the frames to a
specific queue (done with QOS), and then mark the queue as an urgent queue. When an
urgent queue gets data to be transmitted, the circuits will be powered up at once and the
latency will be reduced to the wakeup time.
Web Interface
To configure the EEE Configuration in the web interface:
1. Click Configuration, Port, then EEE
2. To evoke which port wants to enable the EEE function. To evolke which
3. EEE Urgent Queues level and the range from 1 to 8. the queue will
postponethe transmsion until 3000 bytes are ready to be transmitted.
4. Click the save to save the setting
5. If you want to cancel the setting then you need to click the reset button.
It will revert to previously saved values.
.
Figure 3-1.7: The EEE Configuration
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Publication date: March, 2012
Revision A1