The Internet of Things (IoT) is comprised of connected devices which are equipped with sensors, actuators, and applications to provide services for enabling those objects to connect and exchange data. For these connected devices and the IoT network environment, heterogeneous protocols and frameworks have been published and applied to provide novel IoT services in our daily life. On the Internet, most of the services are provided by existing web service providers which are based on the high-performance processor, storage, and stable power supply. However, devices of the IoT are developed for constrained environments using the small size of equipment to provide seamless services ubiquitously. For accessing the constrained devices and existing web service providers using the clients in the IoT networks such as smart homes, the services of servers from the devices and web service providers shall be discovered by the clients using a consistent discovery service. In this paper, a consistent registration and discovery scheme is proposed for the devices and web service providers in the Open Connectivity Foundation (OCF)-based IoT network. For supporting the proposed scheme, an embedded resource directory (RD) server is proposed to provide a consistent registration service that is used for publishing information of devices and web service providers. For the registration, a unified profile format is used that is based on the RESTful API Modeling Language to describes the information of devices and web service providers. Furthermore, the discovery service provides the consistent interface to discover the registered devices and web service providers by the client using the unified user interface. Accordingly, the client can access the resources of devices and web service providers based on the discovered information.
