Augmented Traffic Control: A tool to simulate network conditions

This post introduces Augmented Traffic Control (ATC), a tool developed to simulate various network conditions (2G, Edge, 3G, LTE) for testing and optimizing Facebook's applications. The development involved an initial attempt to create a 2G network using base stations and mobile phones, which proved problematic due to hardware acquisition challenges. The team pivoted to building a Wi-Fi network that could be configured with different simulation speeds. ATC was integrated into the Facebook campus wireless network and its APIs are used in automation. The post details how ATC helped teams like Messenger and download functionality teams identify weaknesses, save development time, and reduce the need for extensive A/B testing. The design for ATC has been open-sourced.