The convergence of the telecommunications and computer industries is nearing a reality leading to service-based business models. The ability to provision services efficiently and quickly will be a competitive differentiator between service providers. This paper describes recent efforts to evaluate performance and predict the scalability of software architectures for provisioning services to end-users. We focus on network services that require the establishment of a Virtual Private Network. An analytical performance model for the service creation process is described. It expresses the high-level performance characteristics of the different subsystems involved in service provisioning. We study the effects of increasing numbers of network elements, end users, and autonomous systems on service provisioning infrastructure.