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Figure 9: Configuring EEE Power Reduction
COMMAND USAGE
◆
EEE works by powering down circuits when there is no traffic. When a port gets data to be
transmitted all relevant circuits are powered up. The time it takes to power up the circuits
is call the wakeup time. The def
ault wakeup time is 17 μs for 1 Gbps links and 30 μs 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 devices have all circuits powered up
when traffic is transmitted. The devices can exchange information about the device
wakeup time using LLDP protocol.
To maximize power savings, the circuit is not started as soon as data is ready to be
transmitted from a port, but instead waits until 3000 bytes of data is queued at the port. To
avoid introducing a large delay when the queued data is less then 3000 bytes, data is
always transmitted after 48 μs, giving a maximum latency of 48 μs plus the wakeup time.
◆
If required, it is possible to minimize the latency for specific frames by mapping the frames
to a specific queue (EEE Urgent Queues). 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.
PARAMETERS
These parameters are displayed:
◆
Port
–
Port identifier.
◆
EEE Enabled
–
Enables or disables EEE for the specified port.
◆
EEE Urgent Queues
–
Specifies which are to transmit data after the maximum latency
expires regardless queue length.
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