AMF controlled handling of the security policy for user plane protection in 5G systems

An Access and Mobility Management Function, AMF, apparatus of a communications system that comprises an access node, AN, configured to communicate through a wireless air interface with user equipment, UEs, and that comprises a Session Management Function, SMF, the AMF comprising:

• at least one processor configured to perform operations comprising:
• receiving an indication of a Max Data Radio Bearer Integrity Protection, DRB-IP, rate indicating a maximum computational capacity of the UE to process DRBs that have integrity protection during protocol data unit, PDU, sessions;
• receiving a protocol data unit, PDU, session establishment request non-access stratum, NAS, message from the UE for establishing a PDU session;
• communicating a PDU session create message toward the SMF;
• and
• receiving a SMF message containing an indication of an allocated DRB-IP rate for DRBs that are to be integrity protected for a PDU session being established,
• wherein adjusting the available DRB-IP rate of the UE based on the Max DRB-IP rate and the allocated DRB-IP rate for DRBs that are to be integrity protected for the PDU session being established, comprises:
• adjusting the available DRB-IP rate of the UE based on a determined difference between the Max DRB-IP rate of the UE and a summation of at least both the DRB-IP rates of flows in any existing PDU sessions that are to be integrity protected by the UE and which are known to the AMF and the allocated DRB-IP rate for DRBs that are to be integrity protected for the PDU session being established.