Details of Grant 

EPSRC Reference:	GR/J87138/01
Title:	MADS: MANAGEMENT OF AVAILABILITY FOR DISTRIBUTED SERVICES
Principal Investigator:	Magee, Professor J
Other Investigators:	Kramer, Professor J Dulay, Dr N Sloman, Professor M
Researcher Co-Investigators:
Project Partners:
Department:	Computing
Organisation:	Imperial College London
Scheme:	Standard Research (Pre-FEC)
Starts:	01 April 1994	Ends:	31 March 1997	Value (£):	193,056
EPSRC Research Topic Classifications:	Networks & Distributed Systems
EPSRC Industrial Sector Classifications:
Related Grants:
Panel History:
Summary on Grant Application Form
i) To investigate the design, construction and management of configurable fault tolerant dstributed services.ii) To investigate the specification of availability policy and to define the set of basic services needed for managing availability.iii) To develop a prototype implementation of a policy driven availability management system based on a set of replicated availability managers.iv) To evaluate the prototype construction and management system in industry supplied case studies.Progress:The project is investigating the techniques and tools necessary for the design, construction and subsequent management of configurable fault tolerant distributed computing services. We are interested primarily in supporting the availability of service in the presence of failures rather than preserving data consistency through the use of transaction mechanisms. The basic building blocks of highly available distributed services are atomic multicast and membership protocols. We have not developed new versions of these protocols but we are providing a design, construction and management framework in which these building blocks can be easily utilised by the builder of a fault tolerant service. To this end, multicast communication abstractions have been provided in the Regis environment. The environment has been used for an initial implementation which supports configurable replicated servers. The techniques for design and construction are based on earlier work carried out by the proposers in the context of the Conic and REX environments for the development of distributed software. The configuration concepts found to be effective in these environments are currently being generalised and made available in the context of the SAA project. We have extended these concepts to the design and construction of configurable fault tolerant distributed systems. Fault tolerant services require on-line management to maintain the continuous availability of that service in the presence of failures. This management service must support the required availability policy for the service and must itself be a fault tolerant service. We are investigating the specification of availability policy and are developing a prototype management service which can automatically support a range of availability policies. A key aspect of the work is the investigation of which aspects of availability impact design and which can be supported by a policy directed availability management service. This work is building on management policy work carried out in the initial phase of the Esprit III SysMan Project. To date, we have concentrated on replication policy and we are developing a policy driven replication manager. In collaboration with Hewlett Packard Laboratories, Bristol, we plan to evaluate the design and construction techniques and prototype availability management system by applying them to a case study in the telecommunication area. We have made progress in defining the case study in collaboration with HP.
Key Findings
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Potential use in non-academic contexts
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Organisation Website:	http://www.imperial.ac.uk