In this work we are interested in the problem of scheduling and redistributing data on master-slave platforms. We consider the case were the workers possess initial loads, some of which having to be redistributed in order to balance their completion times. We assume that the data consists of independent and identical tasks. We prove the NP completeness of the problem for fully heterogeneous platforms. Also, we present optimal polynomial algorithms for special important topologies: a simple greedy algorithm for homogeneous star-networks, and a more complicated algorithm for platforms with homogeneous communication links and heterogeneous workers.