In 2020 more than 50 billions devices will be connected over the Internet. Every device will be connected to anything, anyone, anytime and anywhere in the world of Internet of Thing or IoT. This network will generate tremendous unstructured or semi structured data that should be shared between different devices/machines for advanced and automated service delivery in the benefits of the user's daily life. Thus, mechanisms for data interoperability and automatic service discovery and delivery should be offered. Although many approaches have been suggested in the state of art, none of these researches provide a fully interoperable, light, flexible and modular Sensing/Actuating as service architecture. Therefore, this paper introduces a new Semantic Multi Agent architecture named OntoSmart for IoT data and service management through service oriented paradigm. It proposes sensors/actuators and scenarios independent flexible context aware and distributed architecture for IoT systems, in particular smart home systems