## 3 M2M Information and Services
### M2M Information and Service Technologies
The calls to configure the management objects are done over SyncML. Devices offering services can be managed by Auto Configuration Servers in TR-069 [41]. TR-069 devices are identified by a serial number and a type, and represent services as service objects in the TR-069 data model. These service objects are just service representations which contain parameters for the actual service which can be managed by the ACS. Service objects can be classified by profiles which are specified by the DSLForum. UPnP devices [43] are represented by XML device descriptions, which contain a device ID, the device type and the list of provided services. Each entry in this service list points to an XML service description which contains a service ID, the service type and the actions and states which specify the functionalities of the service. Service description is handled with WSDL file in DPWS [59]. A service's metadata includes information about its relations with other services, such as the hosting service's relationship to the hosted service and vice versa. The application payload data model is defined in the WSDL by means provided by the XML Schema specification, which is an XML based language that can be used to define the properties of other XML based languages. OBix [45] proposes a restful data model based on a highly extensible full-blown object oriented model. It includes classes and even method signatures and objects composed of other objects. It offers a standard library providing the base object types and special purpose classes such as watch, history, batch operations, _etc._ In classic OPC, only pure data was provided, such as raw sensor values, with only limited semantic information, such as the tag name and the engineering unit. OPC UA [46,47] offers more powerful capability for semantic modeling of data. It uses object-oriented techniques, including type hierarchies and inheritance, to model information. The OPC UA Node model allows for information to be connected in various ways, by allowing for hierarchical and non-hierarchical reference type. This facilitates exposing the same information in many ways, depending on the use case. OWL-S [48,49] is an OWL-based Web service ontology, which supplies Web service providers with a core set of markup language, constructs for describing the properties and capabilities of their Web services in unambiguous, computer-interpretable form. OWL-S markup of Web services facilitates the automation of Web service tasks, including automated Web service discovery, execution, composition and interoperation. The SSN ontology [50] describes sensors, the accuracy and capabilities of such sensors, observations and methods used for sensing. Also, concepts for operating and survival ranges are included, as these are often part of a given specification for a sensor, along with its performance within those ranges. Finally, a structure for field deployments is included to describe deployment lifetime and sensing purpose of the deployed macro instrument. Fipa-Device ontology [52,53] can be used as reference to express the capabilities of different devices in a ubiquitous computing system. Some concepts of FIPA are: Device, Hardware Description, Software Description and Connection Description. FIPA can be used by agents when communicating about devices. Agents pass profiles of devices to each other and validate them against the Fipa-Device ontology. Data transmitted in M2M networks need both, the semantics and the level of abstraction, that could make it possible to provide them as a pool of common data available in a given environment and to share them between different applications, without needing to know beforehand the specifics of these data. The physical entities that are sensed and acted need to be modeled with a level of abstraction allowing the M2M system to treat them as generic entities, intrinsic to the environment and not tied to a specific M2M application.