Abstract: A data flow system, where a source 100 transmits a reservation packet to an ingress element 102. The ingress element 102 polices incoming message traffic and collects data flow information. Quality of service differentiation is realized by marking data packets of different data flows. The ingress element 102 registers the reservation packet and forwards the request to a core router 106. The core router 106 evaluates the service level required, and available resources. Based on this evaluation the core router 106 will reject, accept, or modify the received message, indicate the price for the requested level of service, and forward the reservation packet. The process is repeated until the reservation packet reaches the destination 110, which sends a feedback message to the source 100 indicating the result of the reservation packet. After establishing a reservation, source 100 transmits periodic control messages and collects information regarding resource availability, and the flow path.