The X2AP protocol is used to handle the UE mobility within E-UTRAN and provides the following functions:
- Mobility Management
- Load Management
- Reporting of General Error Situations
- Resetting the X2
- Setting up the X2
- eNB Configuration Update
Protocol specification
3GPP TS 36.423 - Evolved Universal Terrestrial Radio Access Network (E-UTRAN); X2 Application Protocol (X2AP)