Today's Digital Systems, particularly systems on chips, are communication-dominated designs. They contain many functionally complex modules that communicate with one another through high-performance data protocols. The latest methodologies for designing such systems usually start with an executable system behavior specification, which the designer uses for functional and performance simulations to validate the system concept. The designer then incrementally refines the specification to obtain a system implementation that meets given constraints, such as data-processing performance or maximum power dissipation, at the desired abstraction level-for example,the register-transfer level(RTL).At the system level, communication