Probabilistic Latency Analysis of the Data Distribution Service in ROS 2

--Robot Operating System 2 (ROS 2) is now the de-facto standard for robotic communication, pairing UDP transport with the Data Distribution Service (DDS) publish-subscribe middleware. DDS achieves reliability through periodic heartbeats that solicit acknowledgments for missing samples and trigger selective retransmissions. In lossy wireless networks, the tight coupling among heartbeat period, IP fragmentation, and retransmission interval obscures end-to-end latency behavior and leaves practitioners with little guidance on how to tune these parameters. T o address these challenges, we propose a probabilistic latency analysis (PLA) that analytically models the reliable transmission process of ROS 2 DDS communication using a discrete-state approach. By systematically analyzing both middleware-level and transport-level events, PLA computes the steady-state probability distribution of unacknowledged messages and the retransmission latency. Our findings establish a theoretical basis to systematically optimize reliability, latency, and performance in wireless industrial robotics. Communication has become an increasingly critical factor in modern robotics. Conventional fixed-station robots have long relied on wired links-such as Ethernet-based fieldbuses-for control and data exchange, benefiting from their stability and low latency. For mobile robots and multi-robot systems, however, the need to cut the tether and adopt wireless communication is rapidly growing [1].