摘要: The method of projections is a new approach to reduce the complexity analyzing nontrivial communication protocols. A protocol system consists network entities and channels. Protocol interact by exchanging messages through channels; in transit may be lost, duplicated as well reordered. Our intended for protocols with several distinguishable functions. We show how construct image each function. An specified just like real protocol. said faithful if it preserves all safety liveness properties original concerning projected smaller than can typically more easily analyzed. Two examples are employed herein illustrate our method. application this verify version high-level data link control (HDLC) described companion paper.