LTE - high level architecture

Above is a simplified view of LTE architecture to get started. For people familiar with  GPRS technology below is the parallelism just for understanding. As expected LTE is much advanced and supports lot more functionalities
LTE                                                              GPRS/UMTS
SGW( Service Gateway)                      SGSN
PDN                                                    GGSN
EPS                                                      PDP
nodeB                                                  enodeB

LTE uses GTP-V2 for control protocol and GTP-V1 for User plane. As for as GTP-I is concerned it is of REV8. Rev 8 is the basic release from GSM that most of the operators are adhering to.