9.3.2.2 Handover and redirection

The source NG-RAN node decides between handover or redirection to EPS based on radio criteria and availability of the N26 interface.

NOTE: Information about the availability of the N26 interface may be configured by OAM at the NG-RAN.

Inter RAT handover is characterised by the following:

• The Source RAT configures Target RAT measurement and reporting.
• The source RAT decides on the preparation initiation and provides the necessary information to the target RAT in the format required by the target RAT.
• Radio resources are prepared in the target RAT before the handover.
• The RRC reconfiguration message from the target RAT is delivered to the source RAT via a transparent container, and is passed to the UE by the source RAT in the handover command.
• In-sequence and lossless handovers are not supported.
• Security procedures for handover to E-UTRA/EPC should follow E-UTRA handover procedures.