Section: 5.3.5 RRC reconfiguration 5.3.5.1 General
Content: Figure 5.3.5.1-1: RRC reconfiguration, successful Figure 5.3.5.1-2: RRC reconfiguration, failure The purpose of this procedure is to modify an RRC connection, e.g. to establish/modify/release RBs/BH RLC channels/Uu Relay RLC channels/PC5 Relay RLC channels, to perform reconfiguration with sync, to setup/modify/release measurements, to add/modify/release SCells and cell groups, to add/modify/release conditional handover configuration, to add/modify/release conditional PSCell change or conditional PSCell addition configuration, to add/modify/release LTM configuration. As part of the procedure, NAS dedicated information may be transferred from the Network to the UE. RRC reconfiguration to perform reconfiguration with sync includes, but is not limited to, the following cases: - reconfiguration with sync and security key refresh, involving RA to the PCell/PSCell, MAC reset, refresh of security and re-establishment of RLC and PDCP triggered by explicit indicators; - reconfiguration with sync but without security key refresh, involving RA to the PCell/PSCell, MAC reset and RLC re-establishment and PDCP data recovery (for AM DRB or AM MRB) triggered by explicit indicators. - reconfiguration with sync for DAPS and security key refresh, involving RA to the target PCell, establishment of target MAC, and - for non-DAPS bearer: refresh of security and re-establishment of RLC and PDCP triggered by explicit indicators; - for DAPS bearer: establishment of RLC for the target PCell, refresh of security and reconfiguration of PDCP to add the ciphering function, the integrity protection function and ROHC function of the target PCell; - for SRB: refresh of security and establishment of RLC and PDCP for the target PCell; - reconfiguration with sync for DAPS but without security key refresh, involving RA to the target PCell, establishment of target MAC, and - for non-DAPS bearer: RLC re-establishment and PDCP data recovery (for AM DRB or AM MRB) triggered by explicit indicators. - for DAPS bearer: establishment of RLC for target PCell, reconfiguration of PDCP to add the ciphering function, the integrity protection function and ROHC function of the target PCell; - for SRB: establishment of RLC and PDCP for the target PCell. - reconfiguration with sync for direct-to-indirect path switch, not involving RA at target side, involving re-establishment of PDCP /PDCP data recovery (for AM DRB) triggered by explicit indicators, and - reconfiguration with sync for LTM cell switch (without security key refresh), and - involving or not involving RA to the target LTM candidate SpCell according to a network indication; - MAC reset; - depending on a network indication, re-establishment of RLC and PDCP data recovery (for AM DRB). - reconfiguration with sync for LTM cell switch (without security key refresh), and - involving or not involving RA to the target LTM candidate SpCell according to a network indication; - MAC reset; - depending on a network indication, no re-establishment of RLC. In (NG)EN-DC and NR-DC, SRB3 can be used for measurement configuration and reporting, for UE assistance (re-)configuration and reporting for power savings, for IP address (re-)configuration and reporting for IAB-nodes, to (re-)configure MAC, RLC, BAP, physical layer and RLF timers and constants of the SCG configuration, to reconfigure PDCP for DRBs associated with the S-KgNB or SRB3, to reconfigure SDAP for DRBs associated with S-KgNB in NGEN-DC and NR-DC, to add/modify/release conditional PSCell change configuration, and (re-)configure the LTM configuration associated with the SCG (only in NR-DC), provided that the (re-)configuration does not require any MN involvement, and to transmit RRC messages between the MN and the UE during fast MCG link recovery. In (NG)EN-DC and NR-DC, only measConfig, radioBearerConfig, conditionalReconfiguration, ltm-Config (only in NR-DC), bap-Config, iab-IP-AddressConfigurationList, otherConfig, appLayerMeasConfig and/or secondaryCellGroup are included in RRCReconfiguration received via SRB3, except when RRCReconfiguration is received within DLInformationTransferMRDC. When a clause of 5.3.5 is executed due to an LTM cell switch execution (i.e., as specified in 5.3.5.18.6) or due to a conditional reconfiguration execution for subsequent CPAC (i.e., as specified in 5.3.5.13.8), every appearance of "the received" before RRCReconfiguration, before a field name, or before an IE name, refers to the RRCReconfiguration, to the field name or to the IE, respectively, that was generated and stored by the UE as specified in 5.3.5.18.6 or 5.3.5.13.8.