gured to the UE in preparation for the procedure that establishes MR-DC, that is the SN Addition procedure described in Section 4.3.4.3.1, are configured by the node serving the UE, and becoming the MN when the procedure successfully com- pletes. But in the case of intra-secondary node mobility, as described in Section 4.3.4.3.2, UE measurements are configured by the SN, if required in coordination with the MN. The SN Change procedure, described in Section 4.3.4.3.3, can be triggered by both the MN (only for inter-frequency SN Change) and the SN. In the first case, UE measurements are con- figured by the MN but in the latter they are configured by SN, which also processes the measurement reports, with no need for providing the measurement results to the MN. Measurement reports for measurements configured by the SN are sent by the UE directly to the SN on SRB3, if SRB3 is configured. Otherwise, reports for measurements configured by the SN are sent on SRB1 to the MN first, and then forwarded via the X2 or Xn network interface to the SN. Measurement results can be exchanged among the involved network nodes during the different mobility procedures. In an SN Change procedure initiated by the MN, measurement results related to the target SN can be provided by the MN to the target SN. In an SN Change procedure initiated by the SN, measurement results of the target SN can be forwarded from the source SN to the target SN via the MN. In an inter-MN handover procedure, measurement results related to the SN can be provided by the source MN to the target MN. To be able to perform measurements on the different serving or not serving frequencies, a UE might need to be configured with gaps during which measurements can be performed. A UE can be configured with a single measurement gap configuration ("per-UE" measure- ment gap) or with two measurement gap configurations ("per-FR" measurement gaps): one for the lower frequency range (FR1, below 7 GHz) and one for the upper frequency range (FR2, above 7 GHz), depending on the UE c