A method of generating, by a single radio link control entity, hereafter referred to as an RLC entity, lower layer blocks using data segments from higher layer packets (70, 80) for transmission of the higher layer packets from a transmitter to a receiver, the method comprising: encapsulating a final data segment of a first higher layer packet associated with a higher priority first packet flow context, hereafter abbreviated to PFC, together with a remaining data segment of a second higher layer packet associated with a lower priority second PFC in a final higher priority data block wherein, when the final higher priority data block is transmitted from the transmitter to the receiver, transmission of the first higher layer packet is completed and transmission of the second higher layer packet is resumed; and including a transition indicator with the final higher priority data block to indicate a transition within the final higher priority data block from the first higher layer packet to the second higher layer packet, wherein including the transition indicator comprises including: a predetermined length indicator value indicating a number of octets in a data field of the final higher priority data block that are needed to complete the transmission of the final data segment of the first higher layer packet; and a temporary flow identity, hereafter abbreviated to TFI, in the data field of the final higher priority data block, said TFI uniquely associated with the second PFC to which the second higher layer packet belongs. encapsulating a final data segment of a first higher layer packet associated with a higher priority first packet flow context, hereafter abbreviated to PFC, together with a remaining data segment of a second higher layer packet associated with a lower priority second PFC in a final higher priority data block wherein, when the final higher priority data block is transmitted from the transmitter to the receiver, transmission of the first higher layer packet is completed and transmission of the second higher layer packet is resumed; and including a transition indicator with the final higher priority data block to indicate a transition within the final higher priority data block from the first higher layer packet to the second higher layer packet, wherein including the transition indicator comprises including: a predetermined length indicator value indicating a number of octets in a data field of the final higher priority data block that are needed to complete the transmission of the final data segment of the first higher layer packet; and a temporary flow identity, hereafter abbreviated to TFI, in the data field of the final higher priority data block, said TFI uniquely associated with the second PFC to which the second higher layer packet belongs. a predetermined length indicator value indicating a number of octets in a data field of the final higher priority data block that are needed to complete the transmission of the final data segment of the first higher layer packet; and a temporary flow identity, hereafter abbreviated to TFI, in the data field of the final higher priority data block, said TFI uniquely associated with the second PFC to which the second higher layer packet belongs.