We explain the notion of security architecture for Internet of Things (IoT) based on software-defined networking (SDN). In this context, the SDN-based architecture works with or without infrastructure, that we call SDN-Domain. This work describes the operation of the proposed architecture and summarizes the opportunity to achieve network security in a more efficient and flexible with SDN. An overview of existing SDN security applications were discussed and tackles its issues, presenting a new IoT system’s architecture. In this paper we considered the network access control and global traffic monitoring for ad-hoc networks. Finally, we point out architectural design choices for SDN using OpenFlow and discuss their performance implications.