Section: 4.5.6 Mapping between access categories/access identities and RRC establishment cause
Content: When 5GMM requests the establishment of a NAS-signalling connection, the RRC establishment cause used by the UE shall be selected according to one or more access identities (see subclauses 4.5.2 and 4.5.2A) and the determined access category by checking the rules specified in table 4.5.6.1 and table 4.5.6.2. If the access attempt matches more than one rule, the RRC establishment cause of the lowest rule number shall be used. If the determined access category is an operator-defined access category, then the RRC establishment cause used by the UE shall be selected according to table 4.5.6.1 and table 4.5.6.2 based on one or more access identities (see subclauses 4.5.2 and 4.5.2A) and the standardized access category determined for the operator-defined access category as described in subclause 4.5.3. NOTE 1: Following an RRC release with redirection, the lower layers can set the RRC establishment cause or the resume cause to "mps-PriorityAccess" in the case of redirection to an NR cell connected to 5GCN (see 3GPP TS 38.331[ NR; Radio Resource Control (RRC); Protocol specification ]  [30]) or to "highPriorityAccess" in the case of redirection to an E-UTRA cell connected to 5GCN (see 3GPP TS 36.331[ Evolved Universal Terrestrial Radio Access (E-UTRA); Radio Resource Control (RRC); Protocol specification ]  [25A]), if the network indicates to the UE during RRC connection release with redirection that the UE has an active MPS session. NOTE 2: When the UE is acting as a 5G ProSe layer-2 UE-to-network relay UE, it is possible for the lower layer to decide an applicable RRC establishment cause according to the request from the 5G ProSe layer-2 remote UE or according to the indication from upper layers, including the case when the request from the 5G ProSe layer-2 remote UE is for emergency services, as specified in 3GPP TS 38.331[ NR; Radio Resource Control (RRC); Protocol specification ]  [30]. Table 4.5.6.1: Mapping table for access identities/access categories and RRC establishment cause when establishing N1 NAS signalling connection via NR connected to 5GCN Table 4.5.6.2: Mapping table for access identities/access categories and RRC establishment cause when establishing N1 NAS signalling connection via E-UTRA connected to 5GCN