METHOD OF IDENTIFYING NETWORK LAYER PDU

摘要

The invention relates to a method of identifying a protocol data unit in a network layer of an air interface (170) in a cellular radio network; to a cellular radio network; and to a protocol data unit. A network layer usually comprises connection management, mobility management and radio resources management sublayers. In the invention, the radio resources management sublayer is replaced by a radio network sublayer. A protocol data unit header (H) includes a protocol discriminator (PD). Some of the protocol discriminator (PD) values are allocated to the identification of protocol data units in the connection management sublayer (CM) and the mobility management sublayer (MM). According to the invention, at least one unreserved value of the protocol discriminator (PD) is used for identifying protocol data units in the radio network sublayer.