Gatekeeper: A Reliable Reconfiguration Protocol for Real-Time Ethernet Systems

Real-time Ethernet systems are becoming increasingly popular for avionics and embedded applications. By regulating network traffic according to predefined configurations, these protocols enable highly deterministic communication, while still conforming to the Ethernet standard. However, the strengths of a statically configured system become weaknesses when the system requirements are changed. In the worst case, the entire network may need to be reloaded with new configurations, resulting in significant downtime. As a result, there is significant growing interest in reconfiguring real-time Ethernet networks online, without restarting the network. Several recent works focus on minimizing frame loss and configuration conflicts during online reconfiguration. Unfortunately, in doing so, they also sacrifice the system’s ability to tolerate faulty components.In this paper, we describe Gatekeeper, the first reconfiguration protocol for real-time Ethernet systems that minimizes downtime while still tolerating faults. Gatekeeper consists of two main sub-protocols: 1) a reliable distribution protocol that ensures consistent configurations are deployed on all non-faulty devices (i.e., switches and network cards), and 2) a dependable test-and-migrate reconfiguration protocol that allows the system to gain confidence that the configurations are correct as they are rolled out to an increasing number of devices. Our evaluation shows that Gatekeeper has modest overheads, and causes up to 2.5× shorter network disruptions than other solutions.