scope:

Overview and Scope

This service definition is compliant with the UPnP Device Architecture version 1.0 and This service enables implementation of power saving functionality for UPnP devices.

Low power devices implement all or some of the sleep states defined in this document (e.g. Transparent Sleep, Deep Sleep Online and Deep Sleep Offline) and may be in any of those sleep states. Depending on the triggers that cause the device to transition from sleep states, the device can be modeled as a sleep/autonomous device that changes its sleep state autonomously, or a sleep/controlled device that changes its sleep state by actions from a control point. Sleeping devices (i.e., sleep capable devices in a state other than the active or disconnected) are discoverable if they respond to M-Search requests issued by Control Points. Sleeping devices that do not respond to M-Search requests are still discoverable if there is a Basic Power Management Proxy that keeps track of low power devices in the network by caching low power states announced in SSDP messages. A BPMPX is an optional component in the network that is used to cache the low power states of low power devices. A low power aware control point can find a sleeping device by querying it from a Basic Power Management Proxy.

The low power device must implement at least one of the following power states. Table 1 illustrates the relation between the internal UPnP low device power states and user visible power states [IEEE 1621]. Notice that when devices enter Deep Sleep Online or Offline states they will not respond to the UPnP M-Search discovery messages, but a low power aware control points can locate devices in this state by invoking UPnP control action on the optional Basic Power Management Proxy.