At which OSI layer is a source port number added to a PDU during the encapsulation process? Posted on November 2, 2020 by Admin Last Updated on November 2, 2020 by Admin At which OSI layer is a source port number added to a PDU during the encapsulation process? transport layer network layer application layer data link layer For more question and answers: Click Here CCNA 1 ITN v7 – Modules 1 – 3: Basic Network Connectivity and Communications Exam Answers Full 100%