The disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. Provided are an access and mobility management function (AMF) and a method performed by an AMF, including receiving, from a terminal, a registration request message for a protocol data unit (PDU) session including information on a requested slice associated with the PDU session; determining whether the requested slice is allowed and whether the requested slice is for a network slice admission control (NSAC); if the requested slice is allowed for the terminal and is for the NSAC, determining whether the requested slice is exempt from the NSAC for the PDU session; and if the requested slice is exempt from the NSAC for the PDU session, transmitting, to the terminal, a registration accept message as a response to the registration request message.