2 Ventura, Joao 2001 Departamento de Informática Lisbon, Portugal Faculdade de Ciências 80 05/2001 Real-Time Communication Protocols Micro-Protocols Schedulability Analysis Distributed Systems With the increase of processing power and network bandwidth it is possible to build sophisticated distributed hard-real time systems. The construction of such communication systems using the composition of several micro-protocol objects is an approach that has been applied with success in the non real-time arena. This encourages the re-use of protocol components and allows the applications to configure stacks tailored to their needs. To benefit from this approach in hard real-time systems, one must be able to derive the timing behavior of a protocol composition given a description of its protocol objects. This thesis presents a general framework to analyse the timing behavior of protocol stacks derived from the composition of micro-protocols. Individual micro-protocols are described as protocol objects that subscribe and produce events; interactions among adjacent protocols are modeled by the exchange of these events. The protocol implementation is modeled by a set of tasks, each programmed to handle a specific protocol event. To illustrate the use of the framework, a study is presented on the timing analysis of a set of modular fault-tolerant group communication protocols designed for the CAN field-bus: RELCAN and EDCAN. In order to perform this study, an existing software tool was extended to comply with the model requirements. http://dited.bn.pt/31602/index_default.html