PDCP:-

PDCP Protocol entities are located at UE and RNC.

PDCP is used only for U-Plane.

PDCP is used only for Network layer services.

UMTS supports several network layer protocols like IPv4 and IPv6.

Packet Data Convergence Protocol (PDCP) layer PDCP protocol entities are located in the UE and the RNC. This protocol exists only in the user plane and only for services for packet switched services.

One main function of the protocol is transmitting and receiving of network layer data units. UMTS supports several network layer protocols like IPv4 and IPv6.

Another main function of PDCP is to perform IP header compression and decompression. This is mainly because IP was originally designed for fixed networks where the overhead is not a big problem. However, in radio networks like UMTS, radio resources are scarce and IP header compression is crucial to increase channel efficiency, especially if small packets are sent frequently.

1- Transmitting and receiving of network layer data units.2- IP Header compression and decompression.