3GPP 24.501 v20.0.0 — the document's own text
4.5.6 Mapping between access categories/access identities and RRC establishment cause
Taught in 10. Who CT1 writes to, and what the letters count (CT1 — the group that writes what your phone says, in depth).
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 clauses 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 clauses 4.5.2 and 4.5.2A) and the standardized access category determined for the operator-defined access category as described in clause 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 "mpsPriorityAccess" in the case of redirection to an NR cell connected to 5GCN (see 3GPP TS 38.331 [30]) or to "highPriorityAccess" in the case of redirection to an EUTRA cell connected to 5GCN (see 3GPP TS 36.331 [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 [30].
NOTE 3: When the UE is acting as a 5G ProSe multi-hop 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 multi-hop child UE-to-network relay UE, 5G ProSe multi-hop layer-2 remote UE or according to the indication from upper layers, including the case when the request from the 5G ProSe multi-hop child UE-to-network relay UE or 5G ProSe multi-hop layer-2 remote UE is for emergency services, as specified in 3GPP TS 38.331 [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
| Rule # | Access identities | Access categories | RRC establishment cause is set to |
|---|---|---|---|
| 1 | 1 | Any category | mps-PriorityAccess |
| 2 | 2 | Any category | mcs-PriorityAccess |
| 3 | 11, 15 | Any category | highPriorityAccess |
| 4 | 12,13,14, | Any category | highPriorityAccess |
| 5 | 0, 3 | 0 (= MT_acc) | mt-Access |
| 1 (= delay tolerant) | Not applicable (NOTE 1) | ||
| 2 (= emergency) | emergency | ||
| 3 (= MO_sig) | mo-Signalling | ||
| 4 (= MO MMTel voice) | mo-VoiceCall | ||
| 5 (= MO MMTel video) | mo-VideoCall | ||
| 6 (= MO SMS and SMSoIP) | mo-SMS | ||
| 7 (= MO_data) | mo-Data | ||
| 9 (= MO IMS registration related signalling) | mo-Data | ||
| NOTE 1: A UE using access category 1 for the access barring check will determine a second access category in the range 3 to 7 that is to be used for determination of the RRC establishment cause. See clause 4.5.2, table 4.5.2.2, NOTE 6.NOTE 2: See clause 4.5.2, table 4.5.2.1 for use of the access identities of 0, 1, 2, and 11-15. |
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
| Rule # | Access identities | Access categories | RRC establishment cause is set to |
|---|---|---|---|
| 1 | 1 | Any category | highPriorityAccess |
| 2 | 2 | Any category | highPriorityAccess |
| 3 | 11, 15 | Any category | highPriorityAccess |
| 4 | 12,13,14, | Any category | highPriorityAccess |
| 5 | 0, 3 | 0 (= MT_acc) | mt-Access |
| 1 (= delay tolerant) | Not applicable (NOTE 1) | ||
| 2 (= emergency) | emergency | ||
| 3 (= MO_sig) | mo-Signalling | ||
| 4 (= MO MMTel voice) | mo-VoiceCall | ||
| 5 (= MO MMTel video) | mo-VoiceCall | ||
| 6 (= MO SMS and SMSoIP) | mo-Data | ||
| 7 (= MO_data) | mo-Data | ||
| 9 (= MO IMS registration related signalling) | mo-Data | ||
| 10 (= MO exception data) | mo-ExceptionData (NOTE 3) | ||
| NOTE 1: A UE using access category 1 for the access barring check will determine a second access category in the range 3 to 7 that is to be used for determination of the RRC establishment cause. See clause 4.5.2, table 4.5.2.2, NOTE 6.NOTE 2: See clause 4.5.2, table 4.5.2.1 for use of the access identities of 0, 1, 2, and 11-15.NOTE 3: This applies to the UE in NB-N1 mode. |