| We present a method for the automatic derivation of eecient protocol implementations from a formal spec-iication. Optimised eecient protocol implementation has become an important issue in telecommunications systems engineering as recently network throughput has increased much faster than computer processing power. EEciency will be attained by two measures. First, the inherent parallelism in protocol speciications will be exploited. Second, the order of execution of the operations involved in the processing of the protocol data will be allowed to diier from the order prescribed in the speciication, thus allowing operations to be executed jointly and more eeciently. The method will be deened formally which is useful when implementing it as a tool.