Evaluating a Dependable Distributed System with Multiple Critical Tasks
Yinong Chen and Zhongshi He
Highly Dependable Systems Research Programme
University of the Witwatersrand , Johannesburg, South Africa
{yinong, zhe}@cs.wits.ac.za
http://www.cs.wits.ac.za/research/programme.html
Full Paper in Postscript File
Abstract
The aim of our research is to develop a distributed system that
support a variety of tasks. Currently, we are implementing Internet
applications on the system, including firewall, web and mail
applications. These applications have different levels of
dependability requirements. Depending on their criticality, a
single task may execute on one, two or more computer nodes.
Fault tolerant protocols are used to detect the disagreement
among replicas. A reconfiguration protocol is used to identify
the faulty nodes according to the fault reports from the fault
tolerant protocols. It then isolates the faulty nodes from the
system and reallocates their tasks to other working nodes. As
a part of the project, this work focuses on the dependability
analysis. The dependability attributes under modelling are the
reliability of the system and the risk that an unacceptable
packet is accepted in the firewall application.
Keywords: reliability, risk, modelling, fault tolerance.