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NOTE – Detailed functions and architecture of the WoT broker function are given in [ITU-T Y.4400].
There are several ways to interact between a WoT broker and devices such as http-based connection
and web services:
– Web services: enable business entities and applications to intercommunicate openly with
each other over a network. Web service systems have program-language-independent
properties, use message-driven communication, and are easily bound to different transport
protocols [ITU-T Y.2232]. The basic web services for WoT define an interaction
[b-W3C SOAP 0] [b-W3C SOAP 1] between WoT broker and constraint/fully-fledged
device as an exchange of messages.
– In the web services, a service and services descriptions are described [b-W3C WSDL 0].
A service is enabled by a software module deployed on network-accessible platforms
provided by the service provider. The service description contains the details of the
interface and implementation of the service including the data types, operations, binding
information and network location. The service description is supported by a web services
provider.
– Also, in order for an application to take advantage of web services, three behaviours must
take place: the publication of service descriptions, the finding and retrieval of service
descriptions, and the binding or invoking of services based on the service description.
These behaviours can occur singly or iteratively, with any cardinality between the roles. In
detail, these operations are the execution (binding or invoking) of services based on the
service description, finding and retrieval of service descriptions and publication of service
descriptions.
The WoT broker is a web services provider who provides a capability for use to create web
services. The web client and web service application function are the web services requester who
use the services provided by a WSP.

9.2 RESTful web services
The RESTful web services have some efficient properties such as high scalability achieved by the
result of a loosely coupled design and facility for deployment since it builds up on the web
infrastructure and standards.

The REST includes the primacy of resources, identified using URIs, and a uniform interface
generally implemented by the HTTP protocol. Resources are manipulated through representations
portrayed according to a media type (e.g., HTML, Atom, etc.) and some metadata.

The WoT uses HTTP as an application protocol rather than using it as a transport protocol. The
WoT exposes its interface following the REST principle because these technical characteristics
enable services and applications on the WoT to be built as loosely coupled systems which expose
the application programming interface (API) in a uniform manner.

Rec. ITU-T Y.4414/H.623 (11/2015) 803