 the case of a dedicated bearer for voice or video. When the execution of the handover has been completed, the target eNB entity advises the MME entity of this by way of the HANDOVER NOTIFY message. Regarding handover based on the X2 interface the PATH SWITCH REQUEST message is transmitted by the target eNB entity to the MME entity for the transfer of the extremity of the GTP-U tunnel corresponding to the source eNB entity to the target eNB entity. The MME responds with the PATH SWITCH ACKNOWLEDGE message if the response is positive or with PATH SWITCH FAILURE message if not. Signaling Protocols 2.3.4. S1-MME interface management The eNB entity takes the initiative to activate the S1-MME interface by transmitting the S1 SETUP REQUEST message, indicating the list of serving location area. The S1 SETUP RESPONSE message from MME entity contains information relating to the MME entity such as its code number, the pool number to which it belongs and the MNC and MCC codes. The MME entity may respond negatively with the S1 SETUP FAILURE message. Updates to the information about the eNB entity (or the MME entity respectively) are transmitted by the ENB CONFIGURATION UPDATE message (or the MME CONFIGURATION UPDATE message respectively). These messages receive a positive response with the ENB/MME CONFIGURATION UPDATE ACKNOWLEDGE messages or a negative one with the ENB/MME CONFIGURATION UPDATE FAILURE messages. The MME entity notifies the eNB entity of the beginning (or the end respectively) of a state of overload by the OVERLOAD START message (or OVERLOAD STOP message respectively) SO as to avoid being selected for the attachment of a new mobile. 2.4. X2-AP protocol The X2-AP protocol is the signaling exchanged between two eNB entities over the X2 interface. The X2-AP protocol performs the following functions: - mobility management: this function enables the source eNB entity to transfer the connection of a mobile to the target eNB entity; - load management: this function is used by the eNB entities to provide an indication