Provided in one disclosure of the present specification is a method for a wireless device attempting network access. The method may comprise the steps of: an RRC layer of the wireless device receiving, from a cell, a first piece of information relating to an NB-IoT RAT; and an NAS layer in the wireless device determining whether to initiate an NAS signaling process even when a backoff timer is running, wherein the backoff timer may be running due to previously having received a rejection message, and wherein when the wireless device uses an NB-IoT RAT and when the NAS signaling process is for transmitting exception data, it may be determined to initiate the NAS signaling process even though the backoff timer is running. The method may further comprise a step of the NAS layer in the wireless device setting an RRC establishment cause of an RRC connection request message as mobile originating (MO) exception data.