A hierarchical traffic management system comprising at least one traffic management node, the traffic management node comprising: a classifier means operable to identify and classify incoming traffic streams; and a queuing system comprising a plurality of queues arranged in a queue hierarchy tree structure (42, 44, 46), each layer of said queue hierarchy configured to support one or more priority queues, said queuing system operable to apply scheduling policies to said traffic streams, said plurality of queues of the queuing system each comprising; enqueue attributes configured to control a depth of the queue; and dequeue attributes configured to control scheduling of the queue, said dequeue attributes comprising minimum bandwidth, maximum bandwidth, excess bandwidth, and priority, wherein each of said plurality of queues has one or more of said dequeue attributes defined and wherein the priority attribute defines that any offered load in this queue, up to an optionally specified rate, is to be serviced ahead of all other queues or nodes of lower priority connected to the same parent and wherein a burst tolerance parameter, for each layer of hierarchy for which the priority behaviour propagates, is associated with the stream that is enabled with the priority propagation behaviour, the burst tolerance parameter indicating whether or not the stream may burst beyond the rate constraint of the ancestral node before it becomes constrained by the rate and, if so, by how much the stream may burst beyond the rate constraint of the ancestral node such that, while the priority traffic is allowed to exceed the ancestral node rates, its traffic will receive priority service with respect to other traffic at each layer of the hierarchy. a classifier means operable to identify and classify incoming traffic streams; and a queuing system comprising a plurality of queues arranged in a queue hierarchy tree structure (42, 44, 46), each layer of said queue hierarchy configured to support one or more priority queues, said queuing system operable to apply scheduling policies to said traffic streams, said plurality of queues of the queuing system each comprising; enqueue attributes configured to control a depth of the queue; and dequeue attributes configured to control scheduling of the queue, said dequeue attributes comprising minimum bandwidth, maximum bandwidth, excess bandwidth, and priority, wherein each of said plurality of queues has one or more of said dequeue attributes defined and wherein the priority attribute defines that any offered load in this queue, up to an optionally specified rate, is to be serviced ahead of all other queues or nodes of lower priority connected to the same parent and wherein a burst tolerance parameter, for each layer of hierarchy for which the priority behaviour propagates, is associated with the stream that is enabled with the priority propagation behaviour, the burst tolerance parameter indicating whether or not the stream may burst beyond the rate constraint of the ancestral node before it becomes constrained by the rate and, if so, by how much the stream may burst beyond the rate constraint of the ancestral node such that, while the priority traffic is allowed to exceed the ancestral node rates, its traffic will receive priority service with respect to other traffic at each layer of the hierarchy.