Xn Handover Call Flow

This section describes Xn Handover call flow.

Xn Handover Call Flow
Xn Handover Call Flow Description

Step

Description

1

Once signaling that involves the UE, source and destination gNB have taken the decision to handover, the destination gNB constructs a PATH SWITCH REQUEST with the list of PDU sessions that have successfully switched and the list of PDU sessions that were not successful.

2

For each of the PDU Sessions, the AMF constructs a SmContext Modify request and sends it to the corresponding SMF to update the tunnel endpoint ID for the gNB.

3

The SMF responds with either 200 OK or an appropriate cause code.

4

The AMF creates a PATH SWITCH REQUEST ACKNOWLEDGEMENT including PDU sessions that are successful in a success list and the PDU sessions that have failed in a failure list and sends them to the destination gNB.

The AMF clears the source gNB context and attaches the destination gNB context to the UE context.