Device and method of handling a secondary node configuration

A network comprising a first base station (BS), a first distributed unit (DU), a second DU and a central unit (CU) for handling a secondary node (SN) configuration for a communication device, comprising:

• the first BS communicating with the communication device according to a master node (MN) configuration, and the first DU communicating with the communication device according to a first SN configuration;
• the CU transmitting a user equipment (UE) Context Setup Request message comprising the first SN configuration to the second DU;
• the CU receiving a UE Context Setup Response message responding to the UE Context Setup Request message from the second DU, wherein the UE Context Setup Response message comprises a first full configuration indicator and a second SN configuration;
• the CU transmitting a SN Modification Required message comprising the second SN configuration and a second full configuration indicator, to the first BS;
• and
• the first BS transmitting a radio resource control (RRC) message to the communication device, wherein the RRC message comprises the second SN configuration and a third full configuration indicator.

A network comprising a first base station (BS), a first distributed unit (DU), a second DU, and a central unit (CU) for handling a secondary node (SN) configuration for a communication device, comprising:

• the first BS communicating with the communication device according to a master node (MN) configuration, and the first DU communicating with the communication device according to a first SN configuration;
• the first BS transmitting a SN Modification Request message to the CU;
• the CU transmitting a user equipment (UE) Context Setup Request message not comprising the first SN configuration, to the second DU in response to the SN Modification Request message;
• the CU receiving a UE Context Setup Response message responding to the UE Context Setup Request message from the second DU, wherein the UE Context Setup Response message comprises a second SN configuration;
• the CU transmitting a SN Modification Request Acknowledge message comprising the second SN configuration and a first full configuration indicator, to the first BS in response to the SN Modification Request message;
• and
• the first BS transmitting a radio resource control (RRC) message to the communication device, wherein the RRC message comprises the second SN configuration and a second full configuration indicator.