Providing generalized rate monotonic scheduling theory to I/O abstractions over timed token protocol MAC networks

This paper presents a high-level abstraction for remote communication which allows to establish connections with real-time requirements. The approach is based on the idea of structuring applications as modules with a set of external visible data structures which act as I/O ports. Parts can be interconnected using real-time connections. This interconnection is done in a configuration phase and it allows to integrate modules or applications dynamically. Real-time connections produce streams of messages with time constraints. Messages are scheduled by means of a priority model where priorities are assigned following generalized rate monotonic scheduling (GRMS) theory. The proposed system is built over a network with the timed token protocol (TTP) medium access control (MAC). A discussion on how to provide GRMS abstractions over TTP is given. Comparison results between current scheduling algorithms and the proposed model are also provided.