Example embodiments of the present disclosure relate to initiation of small data transmission (SDT). A first device determines whether SDT is allowed to be initiated at a first protocol layer of the first device. In accordance with a determination that the SDT is allowed to be initiated at the first protocol layer, the first device determines whether the SDT is allowed to be initiated at a second protocol layer of the first device. In accordance with a determination that the SDT is allowed to be initiated at the second protocol layer, the first device initiates, via the first protocol layer, a communication procedure for the SDT with a second device. Through this solution, it is possible to avoid unnecessary interactions between protocol layers as well as avoid false resume of the radio bearer when the SDT procedure cannot be performed.