Identify the exact energy feature

Cisco distinguishes Ethernet low-power idle from other port or switch states. Request the applicable device and link-partner support, enabled configuration and stated wake behavior. Do not infer that a product advertised as green networking keeps every required endpoint powered. PoE delivery and Ethernet data behavior should be reviewed separately where the same cable supplies an instrument or camera.

Match the service requirement

Record acceptable latency, continuous links and any polling or synchronization requirement. A low average traffic rate does not establish that an interruption is acceptable. A site can have infrequent messages whose timely receipt matters. The network owner must decide which supported idle functions are acceptable; the wind study should not invent a permissible data gap to increase savings.

Verify the functions actually affected by the chosen feature. A supported reduction in one Ethernet physical interface does not demonstrate equal savings in the complete switch or preserve every powered peripheral automatically.

Verify useful savings at the right boundary

Use comparable input measurements and traffic conditions when estimating the effect. Link-level savings need not equal the reduction at a complete switch's AC input, which includes other ports and housekeeping. Give the integrator the accepted network configuration and electrical profile, including any remaining always-on equipment. A wind package can contribute energy without controlling Ethernet power states. No MARSTON network-management function, wake guarantee or continuous telemetry capability is established merely because a switch supports a named energy-saving feature.