3GPP 38.300 v19.3.0 — the document's own text
6.4.1 Services and Functions
Taught in 5. The radio protocol stack, sublayer by sublayer (TSG RAN — the group that specifies the radio, in depth), 2. The six working groups and the line between them (TSG RAN — the group that specifies the radio, overview), 5. The layers a packet falls through, and the three states a device sits in (TSG RAN — the group that specifies the radio, overview).
The main services and functions of the PDCP sublayer include:
- Transfer of data (user plane or control plane);
- Maintenance of PDCP SNs;
- Header compression and decompression using the ROHC protocol;
- Header compression and decompression using EHC protocol;
- Compression and decompression of uplink PDCP SDUs: DEFLATE based UDC only;
- Ciphering and deciphering;
- Integrity protection and integrity verification;
- Timer based SDU discard;
- For split bearers, routing;
- Duplication;
- Reordering and in-order delivery;
- Out-of-order delivery;
- Duplicate discarding.
Since PDCP does not allow COUNT to wrap around in DL and UL, it is up to the network to prevent it from happening (e.g. by using a release and add of the corresponding radio bearer or a full configuration).