The importance of re-usable Intellectual Properties (IPs) cores is increasing due to the growing complexity of today?s system-on-chip and the need for rapid prototyping. In this paper, we provide a design for verification approach of a PCI-X bus model, which is the fastest and latest extension of PCI technologies. We use two different modeling levels, namely UML and AsmL. We integrate the verification within the design phases where we use model checking and model based testing, respectively at the AsmL and SystemC levels. This case study presents an illustration of the integration of formal methods and simulations for the purpose of providing better verification results of SystemC IPs.