The Serial-GMII (SGMII) is an alternative interface to the GMII, which converts the parallel interface of the GMII into a serial format, radically reducing the I/O count (and for this reason often favored by PCB designers).
The TEMAC solution can be extended to include SGMII functionality by internally connecting its PHY side GMII to the Ethernet 1G/2.5G PCS/PMA or SGMII core from AMD. See Interfacing to Other AMD Ethernet Cores.