PLANET WGSD-10020 - Manual (Page 68)

User’s Manual of WGSD-10020 Series
68
4.2.15 EEE Power Reduction
This page 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.
The EEE Power Reduction screen in Figure 4-2-18 appears.
Figure 4-2-18 EEE Configuration page screenshot
The page includes the following fields:
Object Description
• Port
The switch port number of the logical EEE port.
• EEE Enable
Controls whether EEE is enabled for this switch port.
• EEE Urgent Queues
Queues set will activate transmition of frames as soon as any data is available.
Otherwise the queue will postpone the transmsion until 3000 bytes are ready to