13 Implementation

After verifying the protocol design and possibly evaluating its expected performance the protocol can be implemented in a concrete execution environment. Although at first glance it may not seem so, the implementation is one of the most expensive stages of the protocol development process. It requires a multitude of decisions which have a considerable influence on the efficiency and correctness of the final protocol realization. The implementation stage receives anyhow less attention in Protocol Engineering research compared to the other phases of the protocol development process which is expressed in the small number of publications on this subject. One of the reasons is that implementation experiences are rarely generalized and published because of their strong system relation and the subjective character of implementations. In addition, the implementation phase provides few starting points for formalizations. Implementation in the context of formal description techniques means primarily prototyping, i.e., the execution of specifications on a computer. It primarily serves the validation of the protocol procedures during design. FDT compilers usually support this possibility. The efficiency of the generated code plays a minor role in this form of implementation.