Simulation has been the method of choice for analyzing large, complex, and highly volatile systems. One of these systems is the inter-domain routing infrastructure of the Internet. Despite the need for high quality Border Gateway Protocol (BGP) simulation tools, traditional BGP simulators have limitations either in their modeling fidelity or in their scalability. In this work we introduce BGP++, a scalable BGP simulator that employs state-of-the-art techniques to address the abstraction-scalability trade-off.BGP++ builds on high quality software in network simulation, routing and parallel-distributed simulation to deliver a detailed yet scalable implementation of BGP. Moreover, with respect to the needs of researchers and operators, BGP++ has a CISCO-like configuration language, a seamless partitioning engine for parallel-distributed simulations and a configuration toolset that expedites common simulation configuration tasks.