Dynamic service-aware flow control in packet networks

The present invention, including system methods and computer program product, provides the ability to control the flow of traffic into an aggregated trunk port in a network. This is performed by monitoring the trunk port of an aggregation packet switch for congestion and limiting the traffic flowing into the aggregation packet switch through virtual connections with one or more user network interfaces. An access control system executing an access control algorithm monitors the trunk port and controls the user network interfaces to limit the traffic the passes through the trunk port in the event of traffic congestion. Traffic may be limited on the basis of the class of service, the virtual connection, or other parameters.