Résumé : In this paper, we discuss complexity issues for scheduling divisible workloads on heterogeneous systems under the bounded multi-port model. To our best knowledge, this paper is the first attempt to consider divisible load scheduling under a realistic communication model, where the master node can communicate simultaneously to several slaves, provided that bandwidth constraints are not exceeded. In this paper, we concentrate on one round distribution schemes, where a given node starts its processing only once all data has been received. Our main contributions are (i) the proof that processors start working immediately after receiving their work (ii) the study of the optimal schedule in the case of 2 processors and (iii) the proof that scheduling divisible load under the bounded multi-port model is NP-complete. This last result strongly differs from divisible load literature and represents the first NP-completeness result when latencies are not taken into account.