The TM4C129x family of MCUs provide Ethernet functionally for connected applications in four different configurations. This allows a customer to pick parts that match specific application requirements, package foot print and cost point. To keep things simple, a customer can choose a part with integrated MAC & PHY. What is needed then are some termination resistors, filtering capacitors, magnetics and an RJ45 connector. If a customer needs to connect a special PHY, such as the one with optical interface, choose parts that provide MII interface. However, with a fancy application that requires connection with multiple PHYs, choose parts with RMII interface.