A comparative study of three token ring protocols for real-time communications

When developing distributed scheduling algorithms such as communication protocols, issues in achieving optimal policy and minimizing overhead must be addressed. This problem is examined in the context of a specific distributed system-the token ring communication network. Three token ring protocols are considered which are representative of many existing ones in the sense that they incorporate message time constraints at different levels and implement the earliest deadline first transmission (scheduling) policy at different degrees with different overheads. Through a worst-case analysis, the performance of these three token ring protocols is compared. It is concluded that to evaluate a distributed scheduling algorithm such as a communication protocol, it is necessary to not only consider the scheduling policy employed but also to take into account the overhead incurred due to the implementation of the scheduling policy