4.2 Green Ethernet—Port Power Saving Configuration

The Port Power Saving Configuration page allows you to configure the port power savings features. The following figure shows the Port Power Saving configuration.

Figure 4-16. Port Power Saving Configuration

EEE is a power saving option that reduces power usage when there is low or no traffic utilization. EEE works by powering down circuits when there is no traffic. When a port gets the data transmitted, then all circuits are powered-up. EEE works for ports in the Auto-Negotiation mode, where the port is negotiated to either 1G or 100 Mbit full Duplex mode.

The Port Power Saving Configuration page has the following parameters:

  • Optimize EEE Mode: The switch can be set to optimize EEE for either best power saving or least traffic latency
  • Port: The switch port number of the logical port
  • ActiPHY: Link down power savings enabled. ActiPHY works by lowering the power for a port when there is no link. The port is powered up for a short moment to determine if the cable is inserted.
  • PerfectReach: Cable length power savings enabled. PerfectReach works by determining the cable length and lowering the power for ports with short cables.
  • EEE: Controls if EEE is enabled for this switch port. For maximizing power savings, the circuit is not started when transmit data is ready for a port but is queued until a burst of data is ready to be transmitted. This gives some traffic latency. If desired, it is possible to minimize the latency for specific frames by mapping the frames to a specific queue (mapping done with QOS), and then mark the queue as an urgent queue. When an urgent queue gets data to be transmitted, the circuits are powered-up at once and the latency is reduced to the wakeup time.
  • EEE Urgent Queues: Queues that are set activate transmission of frames as soon as data is available. Otherwise, the queue postpones transmission until a burst of frames can be transmitted.