The development of ever faster processors have made it possible to adapt database technology in controlling the telecom network. The requirements of telecom applications are however not generally known in the database community. This paper analyses the requirement on a database to handle services and locations for millions of mobile telecom users. The paper is based on a thorough analysis of network protocols in a pre-standardisation project of UMTS, a third generation mobile telecom system. The requirements, even on databases supporting million users, are within reach for clusters of a dozen computers of rather modest performance. This paper helps database designers understand the specific requirements that large telecom applications put on databases with regard to performance, response times and availability.