• The Packet Data Convergence Protocol shall perform the following functions:
– Header compression and decompression of IP data streams (e.g., TCP/IP and RTP/UDP/IP headers for IPv4 and IPv6) at the transmitting and receiving entity, respectively. (In Release 99 compression accordingly RFC 2507).
– Transfer of user data. This function is used for conveyance of data between users of PDCP services.
– Maintenance of PDCP sequence numbers for radio bearers that are configured to support lossless SRNS Relocation.
• PDCP uses the services provided by the Radio Link Control (RLC) sublayer.
