Author: Erkka Valtteri Ala-Tauriala

Name of thesis: Network Level Interactions between Intelligent Network Service and ISDN supplementary services

Date: August 18th, 1998

Number of pages: 92

Faculty: Electrical and Communications Engineering

Professorship: S-72 Communications Engineering

Supervisor: Professor Dr. Tech. Seppo J. Halme

Instructor: Antti Pikkusaari, Master of Science

One of the main objectives of Intelligent Networks (IN) is that the introduction of new IN-based services shall not causc any change in ihe existing network. However, at least some level of interaction is almost impossible to avoid. That is why service interaction needs to be given special attention, since a new service, wrongly defined and not sufficiently tested, can easily harm other services and users.

The purpose of this study was to identify the most important network level interactions between the existing switch-based ISDN supplementary services and new IN-services to be introduced into the network. Special attention was given to interactions with those IN-services that are using a wider selection of detection points (DP) for the initial triggering than majority of the services currently in use.

The main concepts of IN, different types of services, categorized causes of interaction, and the relevant standards and recommendations are presented, in order to give the reader some background on the following interaction analysis. Interactions between different types of IN-services and ISDN supplementary services are analyzed in detail. Furthermore, interactions with DX 200 Centrex- and Attendant Service Platform (ASP) services are discussed. The analysis is done from the viewpoint of a Nokia DX 200 SSP-switch.

The study was based on a literature survey and on interviews. The main literature sources were IN-standards, research and seminar papers, and other IN related litera- ture. Several Nokia R&D experts were interviewed.

The study concentrates on identifying mainly harmful interactions. At least in the short run, placing Service Switching Points (SSP) at the local exchanges together with the usage of service interaction indicators, enables sufficient management of these interactions. However, also this approach contains some problematic areas, and in the future more developed management methods may be required.