Overload control and performance evaluation in a Parlay/OSA environment

Abstract: To increase the pace of development and deployment of new services and applications in telecommunication networks, new service architectures have been proposed. Parlay/OSA is one of the proposals that has aroused most attention. By providing network functionality via Application Program Interfaces (APIs), Parlay/OSA facilitates creation of telecommunication services and applications for independent software developers. With Parlay/OSA there is no longer any requirement for knowledge and technical skills of telecommunications when creating new applications. A Parlay/ OSA environment introduces gateways, which provide the applications with abstracted network functionality. A gateway translates the requests for abstracted functionality to telecommunication protocols and signalling. Parlay/OSA is a contract driven architecture where several constraints coexist. To fulfil the constraints and to protect the gateways from shutting down, overload control mechanisms are needed. This thesis proposes and evaluates different overload control mechanisms in a Parlay/OSA environment. The main objectives of the overload control mechanisms are to protect the system and to maintain a high throughput. Important issues that are discussed are measurement strategies, overload control actions, and how different priorities and time constraints should be considered. Also, the proposed overload control mechanisms consider some guiding principles from the specifications of Parlay/OSA. In the scope of this thesis both distributed and single server systems are investigated.