A representative system, apparatus, method and protocol are disclosed for data communication between chiplets or SOCs on a common interposer. A representative system comprises: an interposer; a first integrated circuit arranged on the interposer, the first integrated circuit comprising a first common protocol interface circuit; a communication link coupled to the first common protocol interface circuit; and a second integrated circuit arranged on the interposer, the second integrated circuit comprising a second common protocol interface circuit coupled to the communication link to form a serial protocol interface between the first common protocol interface circuit and the second common protocol interface circuit. Serial data and control packets and parallel data and control packets having specified, ordered fields are also disclosed.