Performance, models and topologies of common channel signalling system number seven.

Abstract

An Intelligent Network (IN) can be visualised as a central computer interconnected to

the telecommunication network that allows the creation and deployment of services as

consumer demand arises. Messages or information are transferred between the central

processor and exchanges by a standardised form of signalling, known as Common

Channel Signalling System Number Seven (CCS7).

The thesis focuses on CCS7 performance, models and topologies. A requirement of

the research entails the study of the CCS7 performance parameters: signalling delays

and signalling network dependability. Signalling delays may be comprised of

signalling message transfer delays within the message transfer part and queueing

delays. Signalling network dependability usually include availability, reliability,

maintainability and network robustness.

For the purpose of modelling, the decomposition of the CCS7 message transfer part

into subsystems is essential. A generic model for the message transfer part was used

to implement certain functionalities of CCS7 in OPNET. OPNET (Optimised

Network Engineering Tools) is a comprehensive engineering system capable of

simulating large communication networks with detailed protocol modelling and

performance analysis. The simulation software (OPNET) and performance parameters

were used to analyse CCS7 networks resulting in the selection of a particular

topology for a given region.

The network structures analysed include the mesh topology, standard quad topology,

hierarchical topology and Telstra's new topology. It was found that the mesh structure

had the best simulated and availability/reliability results but was impractical for large

networks due to the cost implications. This cost factor led to the selection of a

hierarchical signalling system for Kwa-Zulu Natal.