Power-line communication (PLC) is a promising communication technology of constructing IoT (internet of things) systems, and it employs IEEE 1901 as its medium access control (MAC) protocol. Current studies about IEEE 1901 MAC performance analysis do not consider the influence of physical layer's retransmission protocols, i.e., ARQ (automatic repeat request) and HARQ-CC (hybrid ARQ with chase combining). Moreover, how 1901 protocol affect the energy consumption in PLC networks, and whether 1901 protocol has bound performance are also unsolved in these existing works. Focusing on the above problems, we put forward a cross-layered theoretical model to insightfully analyze 1901 protocol, where the impacts of physical layer's retransmission protocols (ARQ and HARQ-CC), channel fading modes and practical configurations (buffer size, finite traffic load, etc.) are comprehensively taken into consideration in the modeling process. On this basis, we derive the closed-form expressions of 1901 MAC metrics considering retransmission protocols. Furthermore, we construct an energy consumption model, and provide the bound performance analysis for 1901 protocol. Finally, we evaluate the performance of 1901 protocol under different retransmission protocols and system parameters, and verify the proposed crosslayered theoretical model. INDEX TERMS Power-line communication (PLC); retransmission protocols; medium access control; IEEE 1901; cross-layered theoretical model; performance evaluation.