Section: 5.3.5.6.7 Multicast MRB addition/modification
Content: The UE shall for each element in the order of entry in the list mrb-ToAddModList: 1> if mrb-Identity value included in the mrb-ToAddModList is part of the UE configuration: 2> if mrb-Identity value included in the mrb-ToAddModList for which mrb-IdentityNew is included (i.e., multicast MRB ID change): 3> update the mrb-Identity to the value mrb-IdentityNew; 2> if the reestablishPDCP is set: 3> if drb-ContinueROHC is included in pdcp-Config: 4> indicate to lower layer that drb-ContinueROHC is configured; 3> if drb-ContinueEHC-DL is included in pdcp-Config: 4> indicate to lower layer that drb-ContinueEHC-DL is configured; 3> re-establish the PDCP entity of this multicast MRB as specified in TS 38.323[ NR; Packet Data Convergence Protocol (PDCP) specification ]  [5], clause 5.1.2; 2> else, if the recoverPDCP is set: 3> trigger the PDCP entity of this MRB to perform data recovery as specified in TS 38.323[ NR; Packet Data Convergence Protocol (PDCP) specification ]  [5]; 2> if the pdcp-Config is included: 3> reconfigure the PDCP entity in accordance with the received pdcp-Config; 1> else if mrb-Identity value included in the mrb-ToAddModList is not part of the UE configuration (i.e., multicast MRB establishment including the case when full configuration option is used): 2> establish a PDCP entity and configure it in accordance with the received pdcp-Config; 2> associate the established multicast MRB with the corresponding mbs-SessionId; 2> if an SDAP entity with the received mbs-SessionId does not exist: 3> establish an SDAP entity as specified in TS 37.324[ Evolved Universal Terrestrial Radio Access (E-UTRA) and NR; Service Data Adaptation Protocol (SDAP) specification ]  [24] clause 5.1.1; 3> if an SDAP entity with the received mbs-SessionId did not exist prior to receiving this reconfiguration: 4> indicate the establishment of the user plane resources for the mbs-SessionId to upper layers. NOTE 1: When setting the reestablishPDCP flag for a radio bearer, the network ensures that the RLC receiver entities do not deliver old PDCP PDUs to the re-established PDCP entity. The network does that e.g. by triggering a reconfiguration with sync of the cell group hosting the old RLC entity or by releasing the old RLC entity. NOTE 2: In this specification, UE configuration refers to the parameters configured by NR RRC unless otherwise stated. NOTE 3: When updating the mrb-Identity, the network ensures new MRBs are listed at the end of the mrb-ToAddModList if they have the same MRB ID as in the existing UE configuration.