A port is to couple to another die over a die-to-die (D2D) link and includes physical layer (PHY) circuitry including a first number of sideband lanes to carry data for use in training and management of the D2D link, and a second number of mainband lanes to implement a main data path of the D2D link. The mainband lanes include a forwarded clock lane, a valid lane, and a plurality of data lanes. A logical PHY coordinates functions of the sideband lanes and the mainband lanes.