Section: W.5 Security protection for interworking between 5MBS and eMBMS
Content: Interworking between 5G MBS and eMBMS is supported at service layer. The procedures for inter system mobility with interworking at service layer is specified in clause 7.4 in TS 23.247[ Architectural enhancements for 5G multicast-broadcast services ]  [103]. The joint BM-SC+MBSF/MBSTF functionality provides the security protection for MBS traffic. During inter-system mobility, when the target system is EPS, the security protection specified in TS 33.246[ 3G Security; Security of Multimedia Broadcast/Multicast Service (MBMS) ]  [102] applies. The security protection specified in present document applies to the case when the target system is 5GS.