When a gigabit Ethernet network adapter is operating at 1000 megabits per second (Mbps), it draws a lot of electrical power. Before such a network adapter transitions to a low-power state, its link speed is typically reduced so that the network adapter draws less power. The reduced link speed enables the network adapter to transition to a low-power state. While changing link speeds during the transition to a low-power state, the network adapter typically loses network connectivity for a short time.
Conversely, when a gigabit Ethernet network adapter transitions to the fully-on state from a low-power state, the network adapter's link speed is increased to its fully operational rate. During this transition, the network adapter might also lose connectivity for a short time.
While a miniport driver's underlying network adapter is transitioning to or from a low-power state, the miniport must not indicate either a change in link speed or a change in connection status. For more information about indicating a change in link speed, see NDIS_STATUS_LINK_STATE. For more information about indicating a change in connection status, see Indicating Connection Status.