OPTIMAL SCHEDULING WITH DEADLINE CONSTRAINTS IN TREE NETWORKS

The problem of scheduling time-critical messages over a tree network i s considered. Messages arrive at any of the nodes and have to reach th e root node before their deadlines expire, else they are considered lo st, The network is assumed to be operating in discrete time and the me ssages need one time unit for transmission from one node to the next a long its path, The arrival and deadline processes are arbitrary, The p olicy which transmits messages with smallest extinction (arrival + dea dline) time at every link is shown to minimize the number of lost mess ages over all time intervals and for every sample path.