# TR-181: Device Data Model for CWMP Endpoints and USP Agents *TR-181 Documentation and Theory of Operations* See for the current TR-181 specification. TR-181 Issue 2 defines version 2 of the Device data model (Device:2). The Device:2 data model applies to all types of TR-069 or USP enabled devices, including End Devices, Residential Gateways, and other Network Infrastructure Devices. The Device:2 data model defined in this Technical Report consists of a set of data objects covering things like basic device information, time-of-day configuration, network interface and protocol stack configuration, routing and bridging management, throughput statistics, and diagnostic tests. It also defines a baseline profile that specifies a minimum level of data model support. The cornerstone of the Device:2 data model is the interface stacking mechanism. Network interfaces and protocol layers are modeled as independent data objects that can be stacked, one on top of the other, into whatever configuration a device might support.