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Dynamically Adaptable Multiservice System

Objective

DAMS-2 aimed to develop an advanced communication system capability addressing the needs of the private communications market. It built on the result of project 1059- DAMS1.

At present, the vast majority of voice and data services are catered for by separate networks employing either circuit- or packet-switched techniques. The main objective of DAMS was to address the problems associated with integrating these services within the business environment. DAMS provides both time-dependent voice and time-independent data services in a fully integrated and cost-effective system matching near-term customer requirements. It implemented and validated the system concepts outlined by DAMS-1 and will also identified the migratory paths necessary to support the new services which will become available in the longer term. DAMS-2 has been based on and complies with international standards.
In a distributed system, data segments can be managed in a fault tolerant way if they are replicated in several identical copies and distributed on data management servers running on different processors. If a server or a processor fails, copies of the data segments may be lost. To preserve fault tolerance during the lifetime of the system, for each data segment copy which is lost due to a server failure, a new copy has to be regenerated on one of the remaining servers. Therefore, all existing servers must be kept under surveillance to detect server or processor crashes as soon as possible. In this paper we describe 2 soultions for this surveillance problem. Both approaches are based on an election algorithm which has to cope with process and communication failures. The election algorithm is presented in detail. The protocols proposed in this paper have been developed as part of a distributed operating system which serves as a base for a distributed telecommunication control system.

The dynamically adaptable multiservice system (DAMS-2) project aimed to develop an advanced communication system capability addressing the needs of the private communications market. At present, the vast majority of voice and data services are catered for by separate networks employing either circuit switched or packet switched techniques. The main objective is to address the problems associated with integrating these services within the business environment. Both time dependent voice and time independent data services in a fully integrated and cost effective system matching near term customer requirements will be provided. Flexibility has been a major concern in the specification of the system. DAMS has been designed around a modular architecture incorporating a variable number of subsystems connected to a high speed backbone ring. This will allow DAMS to interface to other existing local area networks (LAN) so that customers will not waste their initial investment in these systems while still being able to take advantage of new service developments. Dynamic allocation allows efficient use of the bandwidth and hence efficient system performance.
Major aspects of the work will be directed towards the construction of a feasibility prototype for demonstration on a test site. This will provide sufficient infrastructure and software support to enable validated concepts to be ported to a development environment for the early exploitation of a product.
All hardware and software components have been developed and are being tested and integrated with a view to building the complete demonstrator.
The private communications market has traditionally been the driving force for the introduction of new services and facilities. DAMS was seen as the next evolutionary step necessary to meet the considerable demand identified for advanced multimedia services which cannot readily or easily be accommodated by current systems, but which will be required before the eventual introduction of the Integrated Broadband Communications Network (IBCN) in the second half of the 90s.

Flexibility has been a major concern in the specification of the system. DAMS has been designed around a modular architecture incorporating a variable number of subsystems connected to a high-speed backbone ring. This allows DAMS to interface to other existing LANs so that customers will not waste their initial investment in these systems while still being able to take advantage of new service developments. Dynamic allocation allows efficient use of the bandwidth and hence efficient system performance. In the course of the project current ATM (Asynchronous Transmission Mode) developments were considered including aspects of switching, signalling and management.

Major aspects of the work were directed towards the construction of a feasibility prototype for demonstration on a test-site.

Coordinator

Telefonbau und Normalzeit GmbH
Address
Mainzer Landstraße 128-146
60327 Frankfurt Am Main
Germany

Participants (4)

INSTITUTO DE ENGENHARIA DE SISTEMAS E COMPUTADORES
Portugal
Address
Apartado 10105, Rua Alves Redol, 9
1017 Lisboa
JEUMONT SCHNEIDER
France
Address
31-32 Quai De Dion Bouton
92811 Puteaux
L-CUBE INFORMATION SYSTEMS
Greece
Address
Mpotassi, 2
10682 Athenes
UNIVERSITAT POLITECNICA DE MADRID
Spain
Address
Campus De Montegancedo
28660 Madrid