Behavior Change
Once the N2 handover procedure is initiated, the SMF sends Data Radio Bearer (DRB) List IE to the source gNB through the Handover Command Transfer message.
Previous Behavior: The SMF incorrectly sends N3 Uplink (UP) Tunnel Information in Downlink (DL) Forwarding Tunnel IE of Handover Command Transfer message.
New Behavior: The SMF no longer forwards the N3 UP Tunnel Information over Handover Command Transfer message. The SMF forwards DL Forwarding Tunnel Information in Handover Command Transfer message if the same is received from Handover Request Acknowledge Transfer message.
The SMF sends Data Radio Bearer (DRB) List IE to the source gNB through the Handover Command Transfer message if it is received from target gNB in the Handover Request Acknowledge Transfer message. This operation is in compliance with the 3GPP specification 38.413, version 9.3.4.