Reliable Ordered Broadcast With Micro-Protocols

The implementation of a complex high-level protocol is described. The protocol, a reliable ordered broadcast for local networks, is implemented using the micro-protocol framework inside the x-kernel. The internal structure of the protocol is described, with its micro-protocols and events. Based on our experiences with the development of this protocol, some general observations about the framework are provided. 1 Introduction Previous works have shown that writing high-level protocols with the x-kernel may be a hard task, due to difficulties in expressing complex interactions among fine-grained modules. A good example of this can be found in the development of Consul, an atomic ordered reliable broadcast protocol [MPS93]. A new framework has been developed and added to the x-kernel to try to solve this kind of problem. The micro-protocol framework[mic] provides an event-oriented environment in which separate modules (called micro-protocols) may be combined in order to describe the intr..

A Customized Communication Subsystem for FT-Linda

Distributed fault-tolerant systems usually impose much stronger requirements on the underlying communication protocols than do applications developed without fault-tolerance in mind. That is true, for example, of applications composed of processes replicated on multiple hosts, where all replicas must keep the same view of the state of the communication. This paper describes how the communication substrate for a speci c application with strong communication requirements was developed. The application, the runtime system for a fault-tolerant version of the Linda language called FT-Linda, requires a communication substrate capable of providing ordered atomic multicast, failure detection and membership services. The implementation relies on a new framework for the composition of event-driven microprotocols that is used with the x-kernel. Resumo Sistemas distribu dos tolerantes a falhas usualmente imp~oem maiores exig^encias sobre os protocolos de comunicac~ao utilizados do que aplicac~oes desenvolvidas sem o objetivo de se prover toler^ancia a falhas. Tal fato ocorre por exemplo com aplicac~oes desenvolvidas replicando-se um processo em varias maquinas, onde todas as replicas devem manter a mesma vis~ao do estado do sistema. Este artigo descreve o desenvolvimento de um protocolo uma aplicac~ao espec ca, o ambiente de execuc~ao de FT-Linda, uma vers~ao tolerante a falhas da linguagem de coordenac~ao Linda. O sistema exige um protocolo de comunicac~ao capaz de prover detecc~ao de falhas, identi cac~ao de participantes e um servico de \multicast " con avel. A implementac~ao se basea em um novo ambiente para composic~ao de micro-protocolos acionados por eventos que e utilizado em combinac~ao com o x-kernel