Dell EMC SmartFabric OS10 User Guide Release 10.5.0

Energy-efficient Ethernet

Energy-efficient Ethernet (EEE) reduces power consumption of physical layer devices (PHYs) during idle periods. EEE allows Dell EMC Networking devices to conform to green computing standards.

An Ethernet link consumes power when a link is idle. EEE allows Ethernet links to use Regular Power mode only during data transmission. EEE is enabled on devices that support LOW POWER IDLE (LPI) mode. Such devices save power by entering LPI mode during periods when no data is transmitting.

In LPI mode, systems on both ends of the link saves power by shutting down certain services. EEE transitions into and out of LPI mode transparently to upper-layer protocols and applications.

EEE advertises during the auto-negotiation stage. Auto-negotiation detects abilities supported by the device at the other end of the link, determines common abilities, and configures joint operation.

Auto-negotiation performs at power-up, on command from the LAN controller, on detection of a PHY error, or following Ethernet cable re-connection. During the link establishment process, both link partners indicate their EEE capabilities. If EEE is supported by both link partners for the negotiated PHY type, EEE functions independently in either direction.

Changing the EEE configuration resets the interface because the device restarts Layer 1 auto-negotiation. You may want to enable Link Layer Discovery Protocol (LLDP) for devices that require longer wake-up times before they are able to accept data on their receive paths. Doing so enables the device to negotiate extended system wake-up times from the transmitting link partner.