An intermediate network device intercepts a packet flow associated with a communication session between a client device and a server, splits the intercepted packet flow of the communication session into a plurality of application-layer data channels, wherein each application-layer data channel represents an independent stream of application-layer data within the communication session, performs Quality of Service (QoS) processing on the application-layer data channels, combines the plurality of QoS-processed application-layer data channels into a combined packet flow, and outputs the combined packet flow onto the communication session between the client device and the server.