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322 Semantic as an Interoperability Enabler in Internet of Things
infrastructure called “digcovery”, this resolution infrastructure has been developed
in the context of the IoT6 EU Project.
9.2 Semantics as an Interoperability Enabler
As it has been stated in the previous section, different strategies and approaches
could be accomplished to diminish the interoperability challenges that the
Internet of Things arises at different levels as stated in [12, 13] and [19].
The adoption of communication and hardware standards is overcoming
some barriers for accessing devices resources. The devices that implement
standards such as Bluetooth [5], UPnP [6], DLNA [7], Zigbee [8],
6lowPAN [9], Zeroconf [10] and so forth, could be discovered and could
interchange raw data readily. Nonetheless, the way that manufacturers provide
access to devices capabilities is colorful, the devices do not usually include a
large set of communication interfaces for interacting with as much devices as
possible, as it is not either feasible or affordable, and raw data syntax is mostly
manufacturer dependent. Therefore, the interoperability challenges move to a
higher level.
Service Oriented Architecture (SOA) [11] has become a worldwide
adopted strategy for accessing heterogeneous systems capabilities. SOA aims
at making independent two or more processes interacting over a network from
the specific details of the infrastructures supporting such interaction. The SOA
reference model establishes two main roles whenever two systems interact: the
service client is the entity which needs a capability and the service provider
is the entity with enough resources and capabilities to satisfy client needs.
A service is a SOA concept that means the mechanisms that enable a client to
access providers’ capabilities. The SOA model also determines that a service
description is also needed for assisting clients to select the most suitable service
among those available, and for making public each provider offers. The
syntax and the meaning of the statements in the service description must be
understandable by all parts, clients and providers, based on standards. SOA
implementations like Web Services [14] and RESTFul Web Services [15]
really achieve SOA objectives and are worldwide accepted specifications.
The Figure 9.3, outlines how the Service Oriented Architecture paradigm
could leverage interoperability of devices in the Internet of Things. Some
devices like a node participating in a wireless sensors and actuators network,