The Realtek RTL8310SR is a highly integrated Layer 2 switch controller. It integrates one low-power Giga-PHY that support 1000Base-T/100Base-T/10Base-T, and seven FE-PHYs that support 100Base-T/ 10Base-T. Moreover, it provides two extra GMAC for specific applications. Extension GMAC1 supports RGMII(3.3v/2.5v)/MII/RMII/SGMII/1000Base-X/100Base-FX, Extension GMAC2 supports RGMII (3.3v/2.5v/1.8v)/MII/RMII. The RTL8310SR features an embedded 8051 CPU to execute programs via an external SPI flash or EEPROM.