OMNeT++ is a discrete event simulation framework primarily used for modeling and simulating communication networks, computer systems, and other complex systems. It provides a modular architecture that allows users to create simulations using reusable components, making it flexible for various applications. The framework includes a rich set of libraries and tools for building simulations, analyzing results, and visualizing network behavior. OMNeT++ is widely used in academia and industry for research and development, enabling users to test and evaluate different network protocols and architectures in a controlled environment.