Real traffic replay over WLAN with environment emulation

Real traffic replay is one of the solutions used to test network devices over complicated scenarios. Packet traces captured in a real environment hold more details than any mathematical models. However, the lack of packet-replay control and environment emulation might highly affect traffic behaviors, especially in wireless networks. Real traffic replay in wireless networks requires packet-replay control to manage the interactions with the device under test (DUT), and coordinately reproduces environment effects, such as fading, noise, and interference. In this work, we propose a method, called Event-driven Automata-synchronized Replay (EAR), to address real traffic replay over WLAN. EAR transforms the captured packet trace into a sequence of events that follow the IEEE 802.11 protocol. The three-level automata are applied to achieve packet-replay control and synchronize the environment effects in traffic replay with the packets and signals captured in a real environment. We propose a quantitative metric, called the event reproduction ratio (ERR), to evaluate the effectiveness of traffic replay. Our software implementation on the Linux-based system demonstrates that EAR achieves the ERR of 95.9% and 92.45% over the DUT-dependent traffic and fading environments, respectively. Under the same condition, the straight-forward replay can only produce the ERR of 20.6% and 0%, respectively.