Synchronizing transition set approach to protocol conversion

With the proliferation of different network architectures, it has been recognized that protocol conversion is needed for achieving the interoperability between computer networks that implement different protocols. In 1980s, many ad hoc protocol converter construction algorithms were proposed. Understanding the expensiveness and limitations of the ad hoc protocol conversion algorithms, since 1986, researchers have started to study conversion algorithms based on formal models to solve the protocol conversion problem systematically and efficiently. In the meantime, it has been observed by many researchers that formal algorithms based on service specification have in general less complexity at the design stage.;The first part of this dissertation describes a five-step protocol conversion algorithm, the STS (synchronizing transition set) approach, in the service specification CFSM (communication final state machine) model to formally derive a protocol converter. The converter so constructed has the three most desirable properties of a correct protocol converter; namely, conformity property (also known as maximum safety property), liveness property, and transparency property. A formal proof of correctness is also included to show that there is no validation phase necessary at the end of the algorithm which distinguishes the STS approach from other existing service specification approaches (in terms of more correctness/accuracy and less complexity).;In the second part of this dissertation, the STS algorithm with minor modification is applied to protocols in the EFSM (extended finite state machine) model in which the same plausible result is obtained; i.e. a converter so constructed in the EFSM model also always has the aforementioned properties of a correct converter. The EFSM model, which allows multiple-state variables of various types, has more express power than the CFSM model does, and is more practical in specifying complex protocols.;The third part of this dissertation discusses protocol conversion in a multimedia network environment. Due to the characteristics of multimedia networks such as high speed and connectivity, the protocol conversion problem is quite different than that in traditional data networks. The importance of protocol conversion in such an environment is discussed; then, it is shown that the STS approach can be adapted to support protocol conversion effectively in a multimedia network environment.