Embodiments of the invention provide flow control of incoming data packets to data processing resources via a controller that can receive and react to advanced backpressure messages. These advanced backpressure messages are used to rate limit the data packets based one or more of the following factors: traffic class, traffic priority, destination port. The controller can also generate a traffic preference message to an upstream source of the data packets to inform the upstream unit of the most appropriate type of data that should be transmitted downstream at that time, thereby improving the likelihood of the transmitted data being processed in a proper and timely manner by the downstream data processing resources. Embodiments of the invention can improve the performance of a communications system during periods of congestion by ensuring that high-priority traffic has precedence over traffic of lower priority while maximizing utilization of the ingress data path bandwidth.