To cope with the ever growing availability of training data, there have been several proposals to scale machine learning computation beyond a single server and distribute it across a cluster. While this enables reducing the training time, the observed speed up is often limited by network bottlenecks. To address this, we design MLNET, a host-based communication layer that aims to improve the network performance of distributed machine learning systems. This is achieved through a combination of traffic reduction techniques (to diminish network load in the core and at the edges) and traffic management (to reduce average training time). A key feature of MLNET is its compatibility with existing hardware and software infrastructure so it can be immediately deployed. We describe the main techniques underpinning ML- NET and show through simulation that the overall training time can be reduced by up to 78%. While preliminary, our results indicate the critical role played by the network and the benefits of introducing a new communication layer to increase the performance of distributed machine learning systems.