RLC protocol layer exists in UE & eNodeb, It is part of LTE air interface control and user planes.

The main services and functions of the RLC sublayer include:

• Transfer of upper layer PDUs;
• Error Correction through ARQ (only for AM data transfer);
• Concatenation, segmentation and reassembly of RLC SDUs (only for UM and AM data transfer);
• Re-segmentation of RLC data PDUs (only for AM data transfer);
• In sequence delivery of upper layer PDUs (only for UM and AM data transfer);
• Duplicate detection (only for UM and AM data transfer);
• Protocol error detection and recovery;
• RLC SDU discard (only for UM and AM data transfer);
• RLC re-establishment.

Protocol specification

3GPP TS 36.322 - Evolved Universal Terrestrial Radio Access (E-UTRA); Radio Link Control (RLC) protocol specification