Section: 5.5.4.2 ProSe relay transaction identity (PRTI)
Content: Upon receiving a ProSe direct link establishment request from a 5G ProSe remote UE or a 5G ProSe end UE for establishing a secure PC5 unicast link as specified in 3GPP TS 24.554[ Proximity-services (ProSe) in 5G System (5GS) protocol aspects; Stage 3 ]  [19E], the UE shall allocate an available PRTI value for the authentication and key agreement procedure for 5G ProSe UE-to-network relay or 5G ProSe UE-to-UE relay and associate this PRTI value with the 5G ProSe remote UE or the 5G ProSe end UE. The UE shall release the PRTI value allocated to the authentication and key agreement procedure for 5G ProSe UE-to-network relay or 5G ProSe UE-to-UE relay when the authentication and key agreement procedure for 5G ProSe UE-to-network relay or 5G ProSe UE-to-UE relay completes or is aborted.