1. LTE EUTRAN
2. LTE Evolved Packet Core.
LTE EUTRAN: -
EUTRAN consists of eNB.
EUTRAN is responsible for complete radio management in LTE. When UE comes up eNB is responsible for Radio Resource Management, i.e it shall do the radio bearer control, radio admission control, allocation of uplink and downlink to UE etc. When a packet from UE arrives to eNB, eNB shall compress the IP header and encrypt the data stream. It is also responsible for adding a GTP-U header to the payload and sending it to the SGW. Before the data is actually transmitted the control plane has to be established. eNB is responsible for choosing a MME using MME selection function.
As the eNB is only entity on radio side, the whole QoS is taken care by it. It shall mark the packets in uplink, i.e Diffserv based on QCI, and also schedule the data.
Other functionalities include scheduling and transmission of paging messages, broadcast messages, and bearer level rate enforcements based on UE-AMBR and MBR etc.
