XCAT-C++: Design and Performance of a Distributed CCA Framework. n this paper we describe the design and implementation of a C++ based Common Component Architecture (CCA) framework, XCAT-C++. It can efficiently marshal and unmarshal large data sets, and provides the necessary modules and hooks in the framework to meet the requirements of distributed scientific applications. XCAT-C++ uses a high-performance multi-protocol library so that the appropriate communication protocol is employed for each pair of interacting components. Scientific applications can dynamically switch to a suitable communication protocol to maximize effective throughput. XCAT-C++ component layering imposes minimal overhead and application components can achieve highly efficient throughput for large data sets commonly used in scientific computing. It has a suite of tools to aid application developers including a flexible code generation toolkit and a python scripting interface. XCAT-C++ provides the means for application developers to leverage the efficacy of the CCA component model to manage the complexity of their distributed scientific simulations.