3GPP 38.300 v19.3.0 — the document's own text
4.7.4.4 Backhaul RLF Recovery
Taught in 4. What NR actually is, in the shape its own document gives it (TSG RAN — the group that specifies the radio, overview).
When the IAB-node using SA-mode declares RLF on the backhaul link, it can perform RLF recovery at another parent node underneath the same or underneath a different IAB-donor-CU. In the latter case, the collocated IAB-DU and the IAB-DU(s) of its descendant node(s) may retain the F1 connectivity with the initial IAB-donor-CU, while the IAB-MT(s) of the descendant node(s) and all the served UEs retain the RRC connectivity with the initial IAB-donor-CU, in the same manner as for inter-donor partial migration.
The BH RLF recovery procedure for the IAB-node is captured in TS 38.401 [4]. BH RLF declaration for IAB-node and the aspects of RLF recovery by the IAB-MT are handled in clause 9.2.7 of the present document.