White paper charts evolution of Ethernet nomenclature

An instructive evergreen (circa 2011) white paper from Brocade examines how "terms that define Ethernet ports often have two meanings -- one from the standard and one from the industry." The paper explains the industry nomenclature of the most common types of Ethernet ports, and shows how the letters in the nomenclature can be associated with specific meanings. The premise of the document is that Ethernet is continuously expanding into new applications by addressing new reaches, new media, and new speeds on links.

"While original Ethernet supported 500-meter links on coaxial cable, modern 100 GbE links support distances of up to 40 kilometers," states Brocade. "From linking data centers to linking cards within a blade server, Ethernet has become the dominant data communication channel in the world. This paper sheds some light on the nomenclature of Ethernet links that are used in most enterprises today." Included in the paper is a handy appendix that charts out the most common external Ethernet links operating over the two general types of media: copper wires and optical fibers. The appendix notes how while the vast majority of copper links use Category (Cat) cabling, twin-axial (Twinax) cables are also abundantly deployed.

"The nomenclature to support this wide variety of links has also grown and evolved over the years," continues the analysis. "From [the] basic twisted pair technology of BASE-T, [Ethernet] nomenclature [has] mirrored the evolution of the copper physical layer to include other copper cabling and backplane connections." The paper further notes, "As encoding [has] moved from externally referenced 4B/5B and 8B/10B to internally defined scrambled 64B/66B, the nomenclature [has] changed from BASE-X to BASE-R. The evolution of laser and fiber-optic technologies has also brought changes in the optical nomenclature from F to SR to LR and ER. The industry has also had their say with terms such as short reach, long reach, and extended reach in common use."

View/Download the white paper here.