Application of timed token protocol for communications in an application specific parallel processing architecture for real time control of an MTDC system
d Shyam, H.S. Chandrasekharaiah · 1995
The Timed Token Protocol (TTP) is used to maintain the control action in real time. Every real time system has to provide the specified timely service to its environment. To meet this requirement there are two fundamentally different paradigms: the event triggered approach and the time triggered approach (H. Kopetz, 1993). We consider the time triggered approach. The TTP initiates each of the processes on its arrival. This protocol integrates services such as predictable message transmission, clock synchronization, membership, mode change, and blackout handling. It also provides some features for fault tolerance. The Multi Terminal Direct Current transmission (MTDC) system control considered in this example is achieved by an application specific architecture which uses 5 processing nodes with some specific coprocessors for signal processing, data acquisition and back end graphic display. The key to success in such systems is the timely execution of data processing tasks that reside on different nodes and communicate with one another to accomplish a common goal. End to end deadline guarantees are not possible without a communication network that supports the timely delivery of inter task messages. The Message Passing Kernel (MPK) used with this system provides an efficient mechanism to dynamically configure communication channels and achieve successful data transfer in the most optimal and reliable manner. The MPK uses the 8 links of the transputer for all its communications