A method and system for wireless communication between a router in a moving vehicle, such as a train, and a stationary communication server outside the moving vehicle through at least one external mobile network on at least one link are disclosed. The method comprises: providing a first output buffer and a second output buffer, and determining whether said data stream is of a data type belonging to a set of prioritized data types. In case the data stream is of a data type belonging to the set of prioritized data types, the first output buffer is selected, and in case the data is of a data type not belonging to the set of prioritized data types, the second output buffer is selected.