The present document is an introduction to the SMAC/SLC layer specification for the TC-SES BSM Regenerative Satellite Mesh - A (RSM-A) air interface family. In particular it contains the description of the overall network and SMAC/SLC protocol architecture of the BSM Regenerative Satellite Mesh - A (RSM-A) air interface as seen from the ST. It also describes the various interfaces between the ST and other network elements and the relation between the layers in the ST logical protocol architecture as are discussed in the present document as well as the interactions with other layers in the BSM Regenerative Satellite Mesh - A (RSM-A) protocol architecture.