BGP plays a crucial role in the global communications in-frastructure, and there is a strong need for tools that can be used for analyzing its performance under different scenarios. The size and complexity of the inter-domain routing system often makes simulation the only viable method for such studies. This work addresses the lack of a comprehensive toolbox to simulate BGP. It proposes a flexible topology generator that produces AS-level graphs which are annotated with business relationships. The second component of the toolbox is a light-weight BGP simulator that is capable of capturing routing dynamics, while scaling to network sizes of thousands of nodes. We employ our frame- work to investigate a set of what-if questions concerning the impact of different topology parameters on BGP dynamics. This investigation shows how our proposed framework can help in gaining important insights on inter-domain routing dynamics.