A network device determines the traffic specification values based on the session values that represent the application parameters of an application, which is provided differentiated service levels. A user of the network device may provide and/or choose the session values. The network device may generate one or more streams corresponding to a plurality of the applications. Each stream may comprise one or more traffic instances. The network device may assign a priority value to each stream and instance identifier to each traffic instances within the stream to manage the transfer of data units.