A system using scheduled times for transmission at each link guarantees bandwidth for transmitting data across a packet network. A scheduling agent determines availability of data paths across a network according to pre-selected criteria and real-time network topology information. Precise schedules are determined for transmission and reception appointments for data packets to traverse each link and switch in the network including compensation for transmission delays and switch latencies, resulting in a fixed packet flow itinerary for each connection. Itineraries are communicated to schedule-aware switches and endpoints and appointment times are reserved for transmission of the scheduled data packets. Scheduled packets arriving at each switch are forwarded according to their predetermined arrival and departure schedules, rather than their headers or contents, relieving the switches from making real-time routing decisions. Any unscheduled transmission times remain available for routing of unscheduled packets according to their IP headers. Real-time transmission of data can be guaranteed in each scheduled path, and schedule selection criteria may be adjusted according to network utilization and tolerable setup delay and end-to-end delay.