A logical quality-of-service management method for peer-to-peer networks uses a special group service for QoS management within peer-groups. This group service determines and assigns a budget per time unit for each peer. Such time unit may be in the range of milliseconds or few seconds. It may also determine a group budget for the peer-group. While a peer uses bandwidth, i.e. while it sends or receives data, its budget is decreased. When a peer has exhausted its budget, it has to lower its priority for transferring or receiving data. Each peer is responsible for keeping its own budget. If a peer does not keep the conditions, other peers may have the right to deny the data transfer from that peer. The QoS service function is advertised in peer-group advertisement messages.