Recommendation ITU-T Y.2121 specifies the requirements for the support of the flow-state-aware (FSA) transfer capability in a next generation network (NGN). The FSA transfer capability provides QoS controls that operate on a per-flow basis, allowing flows to receive different treatment depending on signalled parameters. These parameters are requested using in-band signalling. The parameters contained in these signals are includedin the "flow state" maintained on each flow at each FSA node.