What does LTE X2 connectivity mean?
LTE X2 connection, X2AP, X2U, eNB.
LTE X2 connections : This defines interface between two E-UTRAN NodeB’s (eNB’s). This interface can support both data X2U and control X2AP. In some scenarios only X2AP interface is implemented and others only X2U interface.
In most architecture’s its shown as a direct connection between eNodeB’s. For implementations, its physically routed through transport connections similar to S1 interface connections. The LTE connection’s between eNB’s S1 and X2 are shown in diagram below.