Author: Jari Augustin

Name of the thesis:Dimensioning and Performance Modelling of Common Channel Signalling Transfer Points

Date: 15 October 1998

Number of pages: 90

Faculty: Electrical and Telecommunications Engineering

Professorship: S-72 Communications Engineering

Supervisor: Professor Seppo J. Halme

Instructor: Janne Kankare, Lic.Tech.

The load of common channel signalling networks is being increased through the introduction of new services. Especially ISDN supplementary services and the increasing use of mobile communication and intelligent network services load the network, This may lead to a performance degradation of the signalling network, which affects both the quality of the new services and of the services already offered in the network. Thus, the performance and the capacity of network elements need to be examined.

In this thesis a performance model of the DX 200 system signalling transfer point has been created. Each layer of the common channel signalling protocol stack was examined and its influence on the performance was either calculated or measured. Also the capacity of the signalling transfer point was presented.

It was discovered that the bottleneck of the signalling transfer point is the 64-kbit/s signalling data link. In some situations it may have an impact of 90% on the total performance of the signalling transfer point. Other bottlenecks in the DX 200 system are for example the message bus interface and the backplanebus. In dimensioning signalling transfer points especially the capacity of signalling links and the loads of the processors must be examined.

The information for this thesis was gathered by studying literature, recommendations specified by international standardisation organisations and by carrying out traffic measurements.