According to the seven-layer OS1 (Open System Interconnection) reference model, a communication system can be logically decomposed into layers, each responsible for a specific set of protocol entities. Many approaches have been proposed for the formal specification, validation, and implementation of protocol entities. However, approaches are still lacking for communication systems because the inter-layer synchronization is not clearly defined. This paper presents an approach for automatic communication system development and discusses a semiautomatic implementation of a real-word communication system. We first give a generalized communication system framework (GCSF), which is a universal environment for various communication systems. We then introduce a layered communicating finite state machine (L-CFSM) to specify communication systems. Given an L-CFSM, a communication system generator can automatically produce an executable communication system, based upon the GCSF. The communication system generator is a process of developing communication systems.We have implemented a communication system generator on DOS and UNIX enviornments, in which a communication system with several real-word protocols from DoD and IEEE 802 protocol standards organizations has been sucessfully developed.
IntroductionThe objective of developing a communication system generator is to provide a systematic way of designing communication systems so that their correctness can be ensured. According to the seven-layer OS1 (Open System Interconnection) reference model, which was proposed by the International Standards Organization (ISO), a communication system can be logically decomposed into layers, each responsible for a specific set of protocol entities. In this paper we concentrate on the layered communication systems. Based on such systems, we fist propose a Generalized Communication System Framework (abbreviated to GCSF), which is suitable for a variety of target machines. The GCSF includes queue structure, dispatcher, memory manager, time manager, primitive library, and protocol entities. It provides a universal executable environment for various communication systems.The problem of specifying communication systems is much more difficult than that for the classical (sequential) systems. The difficulties are due to the necessity of describing several sequential components that may then cooperate and execute in parallel.The development of a communication system should begin with a formal specification and then proceed with an automatic implementation, in order to attain good reliability and productivity. There are two major requirements for the specification: one is to facilitate the implementation of the communication system and the other is to perform the validation easily.
317.6.30468 protocol validation can be performed on the event manices[6], instead of on protocol entities themselves. If the communication system is logically error-free, then these matrices are downloaded to the GCSF that has been installed in the taget machine. After...
