The picture shows main network elements, interfaces and the protocols used in LTE.
The main interfaces in LTE are Uu, S1-MME, X2, S1-U, S11 and S5.
LTE Uu : -
This is the air interface between UE and eNB. LTE layer 1 is dealt with later. RRC is the protocol that is used for communication between UE and eNB. Above RRC there is a NAS layer in UE. This NAS layer terminates at MME and eNB shall silently pass the NAS messages to MME.
LTE S1-MME: -
eNB and MME communicate using this IP interface. S1-AP is application layer interface. The transport protocols used here is SCTP. (Stream control transmission protocol).
The main interfaces in LTE are Uu, S1-MME, X2, S1-U, S11 and S5.
LTE Uu : -
This is the air interface between UE and eNB. LTE layer 1 is dealt with later. RRC is the protocol that is used for communication between UE and eNB. Above RRC there is a NAS layer in UE. This NAS layer terminates at MME and eNB shall silently pass the NAS messages to MME.
LTE S1-MME: -
eNB and MME communicate using this IP interface. S1-AP is application layer interface. The transport protocols used here is SCTP. (Stream control transmission protocol).
