Method for operating a packet based data network

A method for operating a packet based data network (21; 31), the data network (21; 31) comprising a multitude of nodes (A, B, C, D) and a shared data bus (22; 32), wherein at least some of the nodes (A, B, C, D) add traffic to the data bus (22; 32), and wherein the upstream nodes (A, B, C, D) reserve data transfer capacity of the data bus (22; 32) for downstream nodes (A, B, C, D) by means of a fairness mechanism, is characterized in that at least some of the nodes (A, B, C, D) drop traffic from the data bus (22; 32), and that said fairness mechanism takes into account the drop traffic at downstream nodes (A, B, C, D). The inventive method allows a better bandwidth utilization and uses available resources more efficiently.