Nowadays Network Operators (NOs) are providing service guaranties to customers by largely overprovisioning their networks, but as the Internet keeps growing, this approach is unveiling important issues in terms of cost and management of the network. To optimize the resource usage, and to reduce the existing overprovisioning, in this paper we present a Cross-layer Autonomic Network Management System that permits Service Providers to perform cost-effective network resource reservation with their NOs. In our novel approach, we use the end-user satisfaction level as the metric used to perform the resource provisioning. We show that our system is capable of achieving a high reduction in operational costs for the Service Providers, while keeping proper bounds in the end-user satisfaction for the offered services.