Fault-tolerant hard-real-time communication of dynamically reconfigurable, distributed embedded systems

Building up hard-real-time networks for distributed systems with dynamical structures poses severe design challenges. As the set of nodes varies, the use of protocols, which request a complete setup with every modification, becomes prohibitive. This paper presents a new concept (called TrailCable) that aims at increasing the flexibility in building up hard-real-time communication systems. The concept consists of an extendable network made up of point-to-point connections, with each node acting as a router with an integrated communication scheduler. The protocol offers the possibility to use unallocated bandwidth for periodic data transmissions. Moreover, functionalities that guarantee the communication channels to be fault-tolerant are also included. Through the collection of these properties, the protocol described in this paper is well adapted to highly dynamic, distributed real-time systems. As a case study, this new communication protocol is applied to an innovative railway system, the so-called RailCab.