Disclosed is a wireless communications system, in the preferred embodiment a GSM/EDGE Radio Access Network system, that includes a Logical Link Control layer of a mobile station and a Logical Link Control layer of a Serving General Packet Radio Service Support Node that are coupled together through a Gb interface. The system operates for establishing and operating a plurality of Temporary Block Flows for transferring Packet Data Units in either an uplink or a downlink direction between the Logical Link Control layer of the mobile station and the Logical Link Control layer of the Serving General Packet Radio Service Support Node. The system operates at a level of the Logical Link Control layer and a Radio Link Control layer for distinguishing Packet Data Units belonging to a first Temporary Block Flow from Packet Data Units belonging to a second Temporary Block Flow based on information associated with each Packet Data Unit, and maps the Packet Data Units into the appropriate one of the first Temporary Block Flow or the second Temporary Block Flow based on the information. A method for operating the system is also disclosed.