In a secure network where the network characteristics are not known, a call admission control algorithm and a preemption control algorithm based on a destination node informing the source node of the observed carried traffic are used to regulate the amount of traffic that needs to be preempted by the source. The amount of traffic that needs to be preempted is based on the carried traffic measured at the destination node. The traffic to be preempted is based on the priority of the traffic, where the lowest priority traffic is the first to be preempted until the amount of traffic preempted is sufficient to allow the remaining traffic to pass through the network without congestion.