in the acknowledged and unacknowledged mode; - possible re-segmentation of PDCP frames, in the acknowledged mode, during retransmission of the RLC frame; - re-sequencing of received data, both in the acknowledged and unacknowledged mode; - detection of duplicate data both in the acknowledged and unacknowledged mode. Radio Interface Procedures 4.1.1.3. MAC protocol The MAC protocol provides the following functions: - multiplexing of RLC frames from multiple instances in a transport block; - resource allocation via a scheduling mechanism; - management of retransmission in case of error via the hybrid automatic repeat request (HARQ) mechanism; - management of the random access procedure. 4.1.2. Logical channels The broadcast control channel (BCCH) is a unidirectional common control channel, used only in the downlink for RRC broadcasting of master information block (MIB) and system information block (SIB) messages. The paging control channel (PCCH) is a unidirectional common control channel, used only in the downlink to transport RRC messages for paging. The common control channel (CCCH) is a bidirectional common control channel, used to transmit the first RRC signaling messages when the mobile connects to the eNB entity. The dedicated control channel (DCCH) is a bidirectional dedicated control channel, used to transmit RRC messages when the mobile is connected to the eNB entity. The dedicated traffic channel (DTCH) is a dedicated bidirectional channel, used to transmit unicast IP packets. The multicast control channel (MCCH) is a unidirectional channel used for transmitting RRC messages for control information associated with IP packets transmitted in broadcast mode. The multicast traffic channel (MTCH) is a unidirectional channel used to transmit IP packets in broadcast mode to the mobile. 114 VoLTE and ViLTE 4.1.3. Transport channels 4.1.3.1. Downlink The broadcast channel (BCH) supports the BCCH logical channel including the RRC message relating to MIB system information. The paging channel (PCH) supports the PCC