A packet scheduling method and apparatus is described for enqueuing incoming data packets in sessions, and for storing the sessions in sequential order in service-groups. Each service-group is assigned a nominal service-interval in which time a data packet is to be transmitted, the nominal service-interval of one service-group being faster than the nominal service-interval of another service-group. Within one service-group, one session is serviced until the nominal service-interval of any of the service-groups where there is at least one data packet to be sent is exceeded.