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English (United Kingdom)

Technology for ATD

Status: Completed  
Start date: 1988-01-01 End date: 1990-12-31

The basic assumption of the project is that asynchronous transfer mode (ATM) is the unique transfer mode for all broadband-integrated services digital network (B-ISDN) services. Several alternative ways of introducing ATM have been analysed for a technoeconomic viewpoint. Studies into ATM-related traffic and telecommunications management network (TMN) issues have also been carried out, to provide dimensioning and control procedures that meet the service requirements. The detailed specification of network subsystems was the starting point for the feasibility analysis and specification of generic ATM components. Emphasis is placed on the ATM bearer service (cell transport), though a large part of the control software is common to all subsystems. In the final phase of the project, all subsystems will be integrated in an technology testbed, which may be used to check common functional specifications.
Generic experiments to evaluate and verify source and network traffic characteristics quality of service (QOS) and network performance metrics have been defined. Key results are the definition of a principle set of experiments and an experiment template.
Traffic source and service type models have been defined, and typical traffic mixes examined.
These issues are prerequisites for traffic control efficiency and also for proper engineering methods. Traffic control schemes for usage parameter and call acceptance control were evaluated and assessed. These are still considered to be the basic questions for the proper operation of ATM networks, and achievement of high resource utilisation under QoS constraints.
2 switching techniques have been selected for realization and experimentation: deterministic (M to 1 stage) and multipath (ROXANNE) self routing. A set of 14 components used in different subsystems were defined. Engineering samples of most components are available.
The R1022 ATD technology testbed (RATT) supports: emulation of narrowband (N)-ISDN service over ATM con nections; emulation of television (TV) distribution; video transfer based on both fixed and variable bit rate coding; and emulation of file transfer between conventional personal computer (PC) over the ATM network. Many ATM subsystems are included in the testbed, covering all the most likely network architectures envisaged in practice.