As platforms evolve from employing single-threaded, single-core CPUs to multi-threaded, multi-core CPUs and embedded hardware-assist engines, the simulation infrastructure required for performance analysis of these platforms becomes extremely complex. While investigating hardware/software solutions for Server Network Acceleration (SNA), we encountered limitations of existing simulators for some of these solutions. For example, Light Weight Threading and Asynchronous Memory Copy solutions for SNA could not be modeled accurately and efficiently and hence we developed a flexible trace-driven simulation framework called ASPEN. ASPEN is based on the use of rich workload traces (RWT), which capture the major events of interest during the execution of a workload on a single-threaded CPU and platform and replaying it a multi-threaded architecture with hardware-assist engines. We introduce the overall ASPEN framework and describe its usage in the context of SNA. We believe that ASPEN is a useful performance tool for future platform architects and performance analysts.