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