Almost methods in embedded software modeling take software architecture as one of the crucial parts of the design process. Since a principal role of embedded software is the interaction with its environments, architectures that describe the dynamic aspects are also needed. Although such architectural view is significantly important in embedded software development, the existing approaches do not practically guide the architectural design based on the dynamic aspects. In this paper, we propose an operational architecture to represent the dynamic aspects of an embedded software. Also we explain how to use our operational architecture in the process of embedded software modeling. Our operational architecture effectively reflects interactionbased dynamic behavior of the system, and gives traceability between requirements and design model.