Model Checking Message Delivery Times in SpaceWire Networks

Abstract

This paper presents a model checking framework in Uppaal for finding worst-case message delivery times for periodic and event-driven message flows in a SpaceWire network with wormhole switching. In particular, we focus on segmentation of large messages into smaller packets. We present a collection of timed automata for SpaceWire links and network messages, that capture message segmentation and wormhole blocking. We evaluate our approach on a realistic example network with 4 routers and 16 message flows, two of which are large messages that need to be segmented. Our model can be used to determine the bounds on the possible segment size, and how this size affects the worst-case message delivery times. Model checking time for these experiments ranges from several minutes to several hours, and we further investigate how it depends on the number of flows, the segmentation size, and the message periods.