Editing Ethernet (section)

==Varieties==
{{Main|Ethernet physical layer|Ethernet over twisted pair}}
The Ethernet physical layer evolved over a considerable time span and encompasses coaxial, twisted pair and fiber-optic physical media interfaces, with speeds from {{nowrap|1 Mbit/s}} to {{nowrap|400 Gbit/s}}.<ref name="400Gapproval">{{Cite web |title=[STDS-802-3-400G] IEEE P802.3bs Approved! |publisher=IEEE 802.3bs Task Force |url=http://www.ieee802.org/3/400GSG/email/msg01519.html |access-date=December 14, 2017 |archive-date=June 12, 2018 |archive-url=https://web.archive.org/web/20180612144057/http://www.ieee802.org/3/400GSG/email/msg01519.html |url-status=live }}</ref> The first introduction of twisted-pair CSMA/CD was [[StarLAN]], standardized as 802.3 1BASE5.<ref>{{cite web| url = http://www.cs.nthu.edu.tw/~nfhuang/handouts/Chap04/sld022.htm| title = 1BASE5 Medium Specification (StarLAN)| date = December 28, 1996| access-date = November 11, 2014| website = cs.nthu.edu.tw| archive-date = July 10, 2015| archive-url = https://web.archive.org/web/20150710151536/http://www.cs.nthu.edu.tw/~nfhuang/handouts/Chap04/sld022.htm| url-status = live}}</ref> While 1BASE5 had little market penetration, it defined the physical apparatus (wire, plug/jack, pin-out, and wiring plan) that would be carried over to 10BASE-T through 10GBASE-T.

The most common forms used are [[Ethernet over twisted pair|10BASE-T, 100BASE-TX, and 1000BASE-T]]. All three use twisted-pair cables and [[8P8C modular connector]]s. They run at {{nowrap|10 Mbit/s}}, {{nowrap|100 Mbit/s}}, and {{nowrap|1 Gbit/s}}, respectively.<ref>IEEE 802.3 ''14. Twisted-pair medium attachment unit (MAU) and baseband medium, type 10BASE-T including type 10BASE-Te''</ref><ref>IEEE 802.3 ''25. Physical Medium Dependent (PMD) sublayer and baseband medium, type 100BASE-TX''</ref><ref>IEEE 802.3 ''40. Physical Coding Sublayer (PCS), Physical Medium Attachment (PMA) sublayer and baseband medium, type 1000BASE-T''</ref>

[[Fiber optic]] variants of Ethernet (that commonly use [[Small form-factor pluggable transceiver|SFP modules]]) are also very popular in larger networks, offering high performance, better electrical isolation and longer distance (tens of kilometers with some versions). In general, network [[protocol stack]] software will work similarly on all varieties.<ref>IEEE 802.3 ''4.3 Interfaces to/from adjacent layers''</ref>