We have embarked upon the development of a reusable global information grid (DID) simulation platform in order to support GIG architecture, design and engineering. We followed a classical systems engineering approach to the design of the GIG simulation platform. We have identified a set of useful performance studies to perform related to GIG architecture and design. We present our approach to the design of our GIG simulation platform and the development of a GIG topology model allowing for automated simulation configurations. As an example of the platform's utility, we briefly discuss our initial studies of BGP performance in GIG-like environments. We conclude with a discussion of follow on work on our GIG simulation platform.