A method for controlling a flow rate of multiple data flows at a network node on a path of the data flows includes the following steps. A private restriction token bucket (RTB) and a private guarantee token bucket (GTB) for each of the data flows and a shared token bucket (STB) common to all of the data flows are provided. n tokens are obtained from the RTBi for the data flow i when a message belonging to the data flow i arrives at the node and needs n tokens. An attempt is made to obtain n tokens from the GTBi for the data flow i and/or the STB. The message is transmitted if n tokens are obtained from the GTBi and/or from the STB, otherwise transmission of the message is delayed until n tokens are available in the GTBi and/or in the STB.