In order to keep a pathway for time critical data packets (for example for VoIP calls) a dummy flow of data packets is established between a home hub router (20) and a broadband remote access server (25) being the first gateway to the IP network. Should a call be made from the telephone (23), the dummy flow is replaced for the duration of the call by the packets generated for the VoIP call. The dummy flow is adjusted by increasing or decreasing the number of data packets transmitted in order to ensure that a minimum bandwidth having a tolerable delay is available. The dummy flow works by causing non time critical (i.e. P2P data packet flows) to back off and no modification is required to routers and the like incorporated into the network.