Overview introduces the features and Product Specification introduces the interfaces and registers that are present in the logic of the QSGMII netlist. This chapter assumes a working knowledge of the IEEE 802.3-2008 Ethernet specification [Ref 2] , in particular the Gigabit Ethernet 1000BASE-X sections: clauses 34 through to 37 and SGMII and QSGMII Cisco Specifications.