Content for  TS 38.423  Word version:  18.2.0

The purpose of the F1-C Traffic Transfer procedure is to deliver F1-C traffic between the M-NG-RAN node and the S-NG-RAN node serving a dual-connected IAB-node, where the F1-C traffic is either received from the IAB-node or sent to the IAB-node. The procedure uses UE-associated signalling. This procedure is only applicable to IAB-nodes.

Either the M-NG-RAN Node initiates the procedure by sending the F1-C TRAFFIC TRANSFER message to the S-NG-RAN Node, or the S-NG-RAN Node initiates the procedure by sending the F1-C TRAFFIC TRANSFER message to the M-NG-RAN Node. Upon reception of the F1-C TRAFFIC TRANSFER message, the receiving node, not being the IAB-donor of the IAB-node, shall deliver the contained F1-C traffic to the IAB-node. Alternatively, the receiving node, being the IAB-donor of the IAB-node, shall handle the received F1-C traffic as specified in TS 38.473.

Not applicable.

Not Applicable.

The purpose of the IAB Transport Migration Management procedure is to exchange information between the F1-terminating IAB-donor and the non-F1-terminating IAB-donor of a boundary IAB-node, for the purpose of managing the migration of the boundary and descendant IAB-node traffic between the topologies managed by the two IAB-donors. The procedure can also be used for mobile IAB-node. In this case, the boundary IAB-node refers to the mobile IAB-node and the non-F1-terminating IAB-donor of a boundary IAB-node refers to the RRC-terminating IAB-donor of a mobile IAB-node. The procedure is applicable to inter-donor partial migration, inter-donor RLF recovery and inter-donor topology redundancy cases. The procedure is initiated by the F1-terminating IAB-donor of the boundary IAB-node. The procedure can be used to set up, modify and release (e.g., for the purpose of revoking) the resources under the non-F1-terminating IAB-donor used for serving the offloaded traffic. The procedure uses UE-associated signalling.

The F1-terminating IAB-donor initiates the procedure by sending the IAB TRANSPORT MIGRATION MANAGEMENT REQUEST message to the non-F1-terminating IAB-donor. The non-F1-terminating IAB-donor may respond with the IAB TRANSPORT MIGRATION MANAGEMENT RESPONSE message by indicating:

• Traffic accepted for offloading, within the Traffic Added List IE;
• Already offloaded traffic accepted for modification, within the Traffic Modified List IE;
• Traffic not accepted for offloading, within the Traffic Not Added List IE;
• Already offloaded traffic not accepted for modification within the Traffic Not Modified List IE.

If the Traffic To Be Released Information IE is contained in the IAB TRANSPORT MIGRATION MANAGEMENT REQUEST message, the non-F1-terminating IAB-donor should release all offloaded traffic if the All Traffic Indication IE in the Traffic to Be Released Information IE is set to "true", or release only the offloaded traffic indicated by the Traffic to Be Released Item IE in the Traffic to Be Released Information IE. If the IAB TRANSPORT MIGRATION MANAGEMENT REQUEST message contains the Traffic to Be Released Information IE, the non-F1-terminating IAB-donor shall include the Traffic Released List IE in the IAB TRANSPORT MIGRATION MANAGEMENT RESPONSE message. If the IAB TRANSPORT MIGRATION MANAGEMENT REQUEST message contains the IAB IPv4 Addresses Requested IE or the IAB IPv6 Request Type IE in the IAB TNL Address Request IE, the non-F1-terminating IAB-donor shall, if supported, provide the allocated TNL address via the IAB TNL Address Response IE in the IAB TRANSPORT MIGRATION MANAGEMENT RESPONSE message. If the IAB TRANSPORT MIGRATION MANAGEMENT REQUEST message contains the IAB TNL Address To Remove List IE in the IAB TNL Address Request IE, the non-F1-terminating IAB-donor shall consider that the TNL address(es) are no longer used by the F1-terminating IAB-donor. If the IAB TNL Address Exception IE is contained in the IAB TRANSPORT MIGRATION MANAGEMENT REQUEST message, the non-F1-terminating IAB-donor shall, if supported, configure the related IAB-donor-DU to enable traffic re-routing over the inter-IAB-donor-DU tunnel. If the IAB QoS Mapping information IE is contained in the IAB TRANSPORT MIGRATION MANAGEMENT RESPONSE message, the F1-terminating IAB-donor, shall, if supported, use it to set DSCP and/or IPv6 flow label fields for the downlink IP packets of the offloaded traffic. If the Mobile IAB-MT BAP Address IE is contained in the IAB TRANSPORT MIGRATION MANAGEMENT REQUEST message and this is the first UE-associated signaling for the mobile IAB-MT identified by the Mobile IAB-MT BAP Address IE, the RRC-terminating IAB-donor, shall, if supported, ignore the Non-F1-Terminating IAB-donor UE XnAP ID IE and allocate an XnAP UE ID for the mobile IAB-MT to be used in the IAB TRANSPORT MIGRATION MANAGEMENT RESPONSE message and subsequent procedure(s) for this mobile IAB-MT.

If the non-F1-terminating IAB-donor is not able to accept any traffic for offloading or modification from the F1-terminating IAB-donor, or a failure occurs during the IAB Transport Migration Management procedure, the non-F1-terminating IAB-donor sends the IAB TRANSPORT MIGRATION MANAGEMENT REJECT message with an appropriate cause value to the F1-terminating IAB-donor.

Not applicable.

The purpose of the IAB Transport Migration Modification procedure is to modify the backhaul information of the offloaded traffic in the topology of the non-F1-terminating IAB-donor of a boundary IAB-node. The procedure can also be used to release the resources under the non-F1-terminating IAB-donor used for serving the offloaded traffic, and to transfer the authorization status of the boundary IAB-node. The procedure can also be used to transfer the authorization status information of the mobile IAB-node. The procedure can also be used for mobile IAB-node. In this case, the boundary IAB-node refers to the mobile IAB-node and the non-F1-terminating IAB-donor of a boundary IAB-node refers to the RRC-terminating IAB-donor of a mobile IAB-node. The procedure is applicable to inter-donor partial migration, inter-donor RLF recovery and inter-donor topology redundancy cases. The procedure is initiated by the non-F1-terminating IAB-donor of the boundary IAB-node. The procedure uses UE-associated signalling.

The non-F1-terminating IAB-donor initiates the procedure by sending the IAB TRANSPORT MIGRATION MODIFICATION REQUEST message to the F1-terminating IAB-donor. The F1-terminating IAB-donor responds with the IAB TRANSPORT MIGRATION MODIFICATION RESPONSE message. If the Traffic Required To Be Modified List IE is contained in the IAB TRANSPORT MIGRATION MODIFICATION REQUEST message, the F1-terminating IAB-donor shall update the backhaul information in non-F1-terminating topology for each traffic indicated in the list, and include the Traffic Required Modified List IE in the IAB TRANSPORT MIGRATION MODIFICATION RESPONSE message. If the Traffic To Be Released Information IE is contained in the IAB TRANSPORT MIGRATION MODIFICATION REQUEST message, the F1-terminating IAB-donor shall consider that all offloaded traffic will be released by the non-F1-terminating IAB-donor if the All Traffic Indication IE in the Traffic to Be Released Information IE is set to "true", or that only the traffic indicated by the Traffic to Be Released Item IE will be released by the non-F1-terminating IAB-donor. If the IAB TRANSPORT MIGRATION MODIFICATION REQUEST message contains the Traffic To Be Released Information IE, the F1-terminating IAB-donor shall include the Traffic Released List IE in the IAB TRANSPORT MIGRATION MODIFICATION RESPONSE message. If the IAB TNL Address To Be Added IE is contained in the IAB TRANSPORT MIGRATION MODIFICATION REQUEST message, the F1-terminating IAB-donor shall allocate the TNL address(es) contained in this IE to the boundary IAB-node or the descendant IAB-nodes. If the IAB TNL Address To Be Released List IE is contained in the IAB TRANSPORT MIGRATION MODIFICATION REQUEST message, the F1-terminating IAB-donor shall release the TNL address(es) contained in this IE for the boundary IAB-node or the descendant IAB-nodes. If the IAB QoS Mapping information IE is contained in the IAB TRANSPORT MIGRATION MODIFICATION REQUEST message, the F1-terminating IAB-donor, shall, if supported, use it to set DSCP and/or IPv6 flow label fields for the downlink IP packets of the offloaded traffic. If the IAB Authorization Status IE is contained in the IAB TRANSPORT MIGRATION MODIFICATION REQUEST message, the F1-terminating IAB-donor, shall, if supported, store it and use it accordingly. If the IAB Authorization Status IE is set to "not authorized", the F1-terminating IAB-donor, shall, if supported, initiate actions to ensure that the IAB-node will not serve any UE(s), as defined in TS 38.401. If the Mobile IAB Authorization Status IE is contained in the IAB TRANSPORT MIGRATION MODIFICATION REQUEST message, the F1-terminating IAB-donor, shall, if supported, store it and use it as defined in TS 38.401. If the Mobile IAB-node Authorization Status IE is set to "not authorized", the F1-terminating IAB-donor, shall, if supported, initiate actions to ensure that the mobile IAB node will not serve any UE(s), as defined in TS 38.401.

Not applicable.

Not applicable.

The purpose of the IAB Resource Coordination procedure is to exchange the semi-static radio resource configuration pertaining to a boundary IAB-node and/or its parent node, between the F1-terminating IAB-donor and the non-F1-terminating IAB-donor of a boundary IAB-node, for the purpose of resource multiplexing between the IAB-MT and the IAB-DU of the boundary IAB-node. The procedure can be initiated by the F1-terminating or non-F1-terminating IAB-donor of the boundary IAB-node. The procedure can also be used for mobile IAB-node. In this case, the boundary IAB-node refers to the mobile IAB-node and the non-F1-terminating IAB-donor of a boundary IAB-node refers to the RRC-terminating IAB-donor of a mobile IAB-node. The procedure uses UE-associated signalling.

The F1-terminating/non F1-terminating IAB-donor initiates the procedure by sending the IAB RESOURCE COORDINATION REQUEST message to the non-F1-terminating/F1-terminating IAB-donor. The non-F1-terminating/F1-terminating IAB-donor shall respond with the IAB RESOURCE COORDINATION RESPONSE message to the F1-terminating/non-F1-terminating IAB-donor. If the Boundary Node Cells List IE and/or Parent Node Cells List IE is included in the IAB RESOURCE COORDINATION REQUEST or in the IAB RESOURCE COORDINATION RESPONSE message, the receiving F1-terminating/non-F1-terminating IAB-donor should take this information into account for resource coordination with the sending non-F1-terminating/F1-terminating IAB-donor.

Not applicable.

Not applicable.