A novel routing strategy is proposed to satisfy the various service demands on hard realtime sporadic occurrencehard realtime periodicity and soft realtime in Fiber Channel.This routing strategy gives prior guarantee to the endtoend delay of tasks with higher priority.The conjugate network calculustransforming the Minplus convolution of cascade service curve into addition in transform domainis applied to analyze the delay upperbound in those worst cases.Thus a simplified method is given to calculate the service curve of multiple nodes.In the endan example adopting the above approach is given to achieve the path routing scheme.The simulation results indicate that the delay upperbound of high priority tasks using proposed approach is much lower than that of tasks using no priority classification.