XTP for the NASA space station

The NASA Space Station is a truly international effort; therefore, its communications systems must conform to established international standards. Thus, NASA is requiring that each network-interface unit implement a full suite of ISO protocols. However, NASA is understandably concerned that a full ISO stack will not deliver performance consistent with the real-time demands of Space Station control systems. Therefore, as a research project, the suitability of the Xpress transfer protocol (XTP) is investigated along side a full ISO stack. The initial plans for implementing XTP and comparing its performance to ISO TP4 are described

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

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

An application of an ethernet based protocol for communication and control in automated manufacturing

The exchange of information in the industrial environment is essential in order to achieve complete integration and control of manufacturing processes. At present the majority of devices present in the shop floor environment are still used as stand alone machines. They do not take advantage of the possibilities offered by a communication link to improve the manufacturing process. The subject of this research has been centered on the development of a simple, flexible and inexpensive support system for communication and control of manufacturing processes. As a result, a system with these features has been proposed and implemented on a simulated workcell. The area footwear manufacturing was chosen for modelling the workcell. The components of the manufacturing support system were developed using an object oriented approach which allowed modularity and software reuse. In order to achieve communication between the components, a communication protocol was developed following the process defined in the rapid protocol implementation framework. Ethernet was selected for implementing the lower levels of the protocol. Java, a new object oriented programming language used for the implementation of the system, showed that it could became a promising language for the implementation of manufacturing applications. In particular the platform independence feature of the language allows the immediate porting of applications to systems with different features. The manufacturing cell simulation had shown that the times associated with the manufacturing support system operations are compatible for its use in applications where the response times are in the order of one second