The continuously growing research to establish the quality of service (QoS) enabled multi-service network architecture has identified several essential mechanisms, among which call admission control (CAC) is assuredly one of the most important ones. This mechanism is responsible for keeping the number of ongoing sessions at the appropriate level in the network to meet the QoS requirements. Due to high call admission request rates, often being the case in core networks, it is essential to study and develop fast and scalable admission control functions. In this paper, we propose a new call admission control scheme based on topology aggregation. We use simulations to evaluate the performance of this scheme versus a traditional parameter-based admission control model. The results show that our CAC scheme achieves very good performances in terms of accuracy and scalability.