The Analytical Model of Distributed Interrupt Mechanism in SpaceWire Network

The distributed interrupt mechanism is intended for reliable and low-latency transmission of system signals with acknowledge in SpaceWire networks. Important tasks are rigorous proof of the distributed interrupt mechanism properties and time characteristics calculation. For these purpose the analytical model has built, which describes the distributed interrupt mechanism in terms of graph theory. The article shows basic data, assumptions and notations for graph theory based model building, describes distributed interrupt propagation algorithm in terms of graph. Here is proved the correctness of the algorithm, i.e.: distributed interrupts/acknowledges wave propagation time is finitely; the distributed interrupts/acknowledges wave propagates to all nodes of a graph. The assertions are proved: acknowledge wave to the interrupt does not cross in time with distributed interrupt wave if the interrupt processing time is greater than the maximum interrupt propagation time; the next interrupt wave does not cross with acknowledge wave to the previous interrupt if the time interval between acknowledge receiving and next interrupt generation is greater than the maximum acknowledge wave propagation time. Here are provides algorithm consequence that Interruptcode (Acknowledge-code) from source node (handler node) to all other graph nodes propagates by the shortest path and forms oriented covering tree. The necessity of the distributed Interrupt mechanism parameters restrictions determined looping problem in networks with loops and provides a solution to this problem, which makes changes to the algorithm and prove the correctness of the changes.