Abstract—Fault-tolerant, real-time communication in distributed systems is very important yet difficult to achieve. Traditional protocols like the TCP/IP achieve reliable communication through acknowledgment and retransmission schemes, where one achieves the reliability at the cost of performance. In this paper, we discuss how both the timeliness and fault-tolerance of communication can be achieved by using the concept of real-time channel [1] and exploring the inherent spatial redundancy of a given network topology. Specifically, we show how isolated failure immune real-time channels can be established in wrapped hexagonal mesh networks, thus ensuring timely delivery of messages in the presence of network component failures as long as the failures are isolated. This kind of fault-tolerance cannot be achieved with other commonly-known topologies like rings, rectangular meshes, and hypercubes. The proposed approach is to be implemented in an experimental distributed real-time system, called HARTS [2], whose construction is underway.

Index Terms—Distributed computing systems, fault-tolerant real-time communications, wrapped hexagonal mesh, isolated failure immune networks, real-time channels.