Modelling and Performance Analysis of a Digital Switching System—Case Study of the C-DoT DSS

Abstract

It is now well recognised that modelling and performance analysis is an important and necessary part of the development cycle of any large telecommunication system. In this paper we demonstrate some of the techniques that are used, and the kinds of results that can he obtained, by describing a detailed performance analysis that we have done for the Centre for Development of Telematics' Digital Switching System (C-DoT DSS). We have used a simulation model to evaluate the performance of the Hase Module (ISM). This model yielded an estimate of BM capacity, helped to design and evaluate a new overload control, and showed how BM capacity can be improved by a scheduling change. We have used analytical queuing models to estimate the capacities of the Administrative Processor, and the Space Switch Controller. We have formulated the system overload control problem as a constrained optimisation problem, have solved the problem, and have used simulations to evaluate various adaptive overload control algorithms.

Indexing terms:

• Overload control
• Distributed systems
• Switching system
• Queuing models