Efficient Configuration of Protocol Software for Multiprocessors

Efficient implementation of communication software is of crucial importance for high-speed networks. One way to improve the runtime performance of protocol implementations in the network nodes is the use of parallelism. Formal description techniques like Estelle improve the specification process in many respects and allow for semiautomatic code generation. Therefore, they are now widely accepted. We present a code generator for Estelle that compiles and automatically configures protocol software for a multiprocessor. Software modules are distributed over the available processors and executed concurrently. We report performance results on a KSR1 with 28 available processors under the OSF/1 operating system

An Estelle Compiler for Multiprocessor Platforms

Efficient implementation of communication software is of critical importance for high-speed networks. Parallelism can improve the runtime performance of implementations gained by code generation. Therefore, we have modified an existing Estelle compiler to run under OSF/1. It exploits parallelism not only in the actions of the FSMs, but also in the runtime system of the protocol stack

Hardware/Software Co-design of Communication Protocols

An important aspect in providing high performance distributed systems such as multimedia systems is the combined use of hardware and software in the end systems. System design techniques should allow hardware/software co-design to integrate both means of implementation. In this paper, we show how the standardized formal language Estelle can be used to facilitate co-design. The system will first be designed in Estelle. At the point in time of final decision on which parts to implement in software and which in hardware, the original specification will be split into several partial specifications. The software parts are translated into C code, while the hardware parts are translated into VHDL code for further analysis and development. We present a tool environment which supports the protocol developer in the design and implementation process. A simple Video-on-Demand example shows the usefulness of the tool environment

Efficient Implementation of Estelle Specifications

Efficient implementation of communication software is of critical importance for high-speed networks. We analyze performance bottlenecks in existing implementations and propose two techniques for improvements: The first exploits parallelism not only in the actions of the FSMs, but also in the runtime system of the protocol stack. The second integrates adjacent layers leading to considerable savings in inter-layer interface handling and in the number of transitions occurring in the FSMs. Both techniques are discussed in the context of OSI upper layers, and are based on protocol specification in Estelle

On the Suitability of Estelle for Multimedia Systems

Formal Description Techniques have been widely used for the specification of traditional networked applications. They have not been applied to the specification of new applications such as multimedia systems yet. In this paper, we examine the FDT Estelle with respect to its suitability for multimedia system specification and automatic derivation of efficient implementations. We show that it is possible to specify certain aspects of multimedia systems, but that Estelle is not sufficient for others. The derived implementations often perform badly. We show the reasons and propose to use a slightly modified Estelle syntax and semantics to solve the problems. The implemented solution was tested successfully

Implementing Movie Control, Access and Management - from a Formal Description to a Working Multimedia System

In this paper we describe the tool-supported specification and implementation of a multimedia communication protocol on parallel hardware. MCAM is an application layer protocol for movie control, access and management. We specify the full MCAM protocol together with ISO presentation and session layers in Estelle. Using a code generator, we derive parallel C++ code from the specification. The code is compiled and executed on a multiprocessor system under OSF/1 and on UNIX workstations. Measurements show the performance speedup gained by several different configurations of parallel units. We also report on experiences with our methodology

Review of Estelle and LOTOS with respect to critical computer applications

Man rated NASA space vehicles seem to represent a set of ultimate critical computer applications. These applications require a high degree of security, integrity, and safety. A variety of formal and/or precise modeling techniques are becoming available for the designer of critical systems. The design phase of the software engineering life cycle includes the modification of non-development components. A review of the Estelle and LOTOS formal description languages is presented. Details of the languages and a set of references are provided. The languages were used to formally describe some of the Open System Interconnect (OSI) protocols

Реалізація мережевих протоколів як незалежних процесів

The article reviews the approach to network protocols implementation as independent processes. Usage of the proposed method allows implementation of each network protocol in the stack completely independently from other protocols, that significantly simplifies the task of formal methods application for protocols synthesis. As a result of the research there was proposed and practically tried out a methodology of formal specification of generalized models of network protocols behavior, as well as of external mechanism of their interaction.В статье рассматривается подход к реализации сетевых протоколов как независимых процессов. Использование предлагаемого метода позволяет реализовывать логику каждого сетевого протокола в стеке полностью независимо от других протоколов, что значительно облегчает применение формальных методов для решения задачи синтеза протоколов. В результате исследования сформулирована и опробована методика формального описания обобщенных моделей поведения сетевых протоколов, а также внешних механизмов их взаимодействия

Protocol engineering from Estelle specifications

Bibliography: leaves 129-132.The design of efficient, reliable communication protocols has long been an area of active research in computer science and engineering, and will remain so while the technology continues to evolve, and information becomes increasingly distributed. This thesis examines the problem of predicting . the performance of a multi-layered protocol system directly from formal specifications in the ISO specification language Estelle, a general-purpose Pascal-based language with support for concurrent processes in the form of communicating extended finite-state machines. The thesis begins with an overview of protocol engineering, and a discusses the areas of performance evaluation and protocol specification. Important parts of the mathematics of discrete-time semi-Markov processes are presented to assist in understanding the approaches to performance evaluation described later. Not much work has been done to date in the area of performance prediction from specifications. The idea was first mooted by Rudin, who illustrated it with a simple model based on the global state reachability graph of a set of synchronous communicating FSMs. About the same time Kritzinger proposed a closed multiclass queueing model. Both of these approaches are described, and their respective strengths and weaknesses pointed out. Two new methods are then presented. They have been implemented as part of an Estelle-based CASE tool, the Protocol Engineering Workbench (PE!V). In the first approach, we show how discrete-time semi-Markov chain models can be derived from meta-executions of Estelle specifications, and consider ways of using these models predictively. The second approach uses a structure similar to a global-state graph. Many of the limitations of Rudin's approach are overcome, and our technique produces highly accurate performance predictions. The PEW is also described in some detail, and its use in performance evaluation illustrated with some examples. The thesis concludes with a discussion of the strengths and weaknesses of the new methods, and possible ways of improving them