RRC protocol layer exists in UE & eNodeb, It is part of LTE air interface control plane. The main services and functions of the RRC sublayer include:

• Broadcast of System Information related to the non-access stratum (NAS);
• Broadcast of System Information related to the access stratum (AS);
• Paging;
• Establishment, maintenance and release of an RRC connection between the UE and E-UTRAN
• Security functions including key management;
• Establishment, configuration, maintenance and release of point to point Radio Bearers;
• Mobility functions
• QoS management functions;
• UE measurement reporting and control of the reporting;
• NAS direct message transfer to/from NAS from/to UE.

Protocol specification

3GPP TS 36.331 - Evolved Universal Terrestrial Radio Access (E-UTRA); Radio Resource Control (RRC)