Ethernet - Revision history

Jnc: /* External links */ +Ethernet: An Engineering Paradigm

2025-09-28T15:47:08Z

‎External links: +Ethernet: An Engineering Paradigm

Jnc: Rework to emphasize that only the highest-level host-network interface (the packet format) has remained

2025-03-02T14:56:44Z

Rework to emphasize that only the highest-level host-network interface (the packet format) has remained

Jnc: /* External links */ +Ethernet is Still Going Strong After 50 Years

2025-01-06T20:02:23Z

‎External links: +Ethernet is Still Going Strong After 50 Years

Jnc: /* DIX Ethernet */ +Ethernet Version 2 Versus IEEE 802.3 Ethernet

2023-10-05T20:00:09Z

‎DIX Ethernet: +Ethernet Version 2 Versus IEEE 802.3 Ethernet

Jnc: /* External links */ + A couple of good columns about the Experimental Ethernet

2023-06-01T15:03:47Z

‎External links: + A couple of good columns about the Experimental Ethernet

Jnc: /* External links */ move IEEE 802 Numbers link here

2022-12-31T00:57:51Z

‎External links: move IEEE 802 Numbers link here

Jnc: /* External links */ +spec and announcement

2022-08-06T22:13:10Z

‎External links: +spec and announcement

Jnc: /* Implementation */ taps only used with coax

2022-07-12T11:16:17Z

‎Implementation: taps only used with coax

Jnc: +links, img of vampire tap housing

2022-07-11T13:54:56Z

+links, img of vampire tap housing

Jnc: clean up intro a bit; move address info here

2022-07-11T02:42:10Z

clean up intro a bit; move address info here

← Older revision		Revision as of 15:47, 28 September 2025
Line 63:		Line 63:

	* [https://spectrum.ieee.org/ethernet-ieee-milestone Ethernet is Still Going Strong After 50 Years: The technology has become the standard LAN worldwide]		* [https://spectrum.ieee.org/ethernet-ieee-milestone Ethernet is Still Going Strong After 50 Years: The technology has become the standard LAN worldwide]
		+	* Mark Huang, Eden Miller, Charles Oji, Peter Sun, [https://web.mit.edu/6.933/www/Ethernet.pdf ''Ethernet: An Engineering Paradigm''], 1998 - archived [https://web.archive.org/web/20060811192145/https://web.mit.edu/6.933/www/Ethernet.pdf here]; covers the path by which Ethernet became predominant

	===Experimental Ethernet===		===Experimental Ethernet===

@@ Line 3: / Line 3: @@
 '''Ethernet''' is a family of computer [[data network]]ing technologies commonly used in [[local area network]]s (LANs), metropolitan area networks (MANs) and [[wide area network]]s (WANs).
-The first commercial version was a LAN introduced in 1980 by a consortium of [[Digital Equipment Corporation|DEC]], [[Intel]] and [[Xerox]] (hence its common label at the time, '''DIX Ethernet''',  from the initials of the partners); it was first openly standardized in 1983 as [[IEEE 802.3]].
+Over time, Ethernet has largely replaced competing wired LAN technologies such as [[token ring]], [[Fiber Distributed Data Interface|FDDI]] and [[ARCNET]]. The 'Ethernet' of today is fundamentally different from the original Ethernet, though. As in many similar cases, only the highest levels of the [[interface]] between the two parts (the station and the network) has been retained; the lowest levels of the interface, and the equipment on either side, have been free to transform internally, and on the network side it has done so in a major way.
-That one originally operated at 10 Mbits/second; it has since been refined to support higher [[bit rate]]s and longer link distances (but see 'Parameter contention' below). Follow-on versions have been produced at 100 and 1000 ('Gigabit Ethernet') Mbits/second.
+Two aspects of that interface have remained:
-It was based on, and inspired by, the '''Experimental Ethernet''', done at [[Xerox PARC]] to connect [[Xerox Alto|Altos]]; that operated at 3 Mbits/second.
+The first commercial version was a LAN introduced in 1980 by a consortium of [[Digital Equipment Corporation|DEC]], [[Intel]] and [[Xerox]] (hence its common label at the time, '''DIX Ethernet''', from the initials of the partners); it was first openly standardized in 1983 as [[IEEE 802.3]].
-Over time, Ethernet has largely replaced competing wired LAN technologies such as [[token ring]], [[Fiber Distributed Data Interface|FDDI]] and [[ARCNET]].
+That one originally operated at 10 Mbits/second; it has since been refined to support higher [[bit rate]]s and longer link distances (but see 'Parameter contention' below). Follow-on versions have been produced at 100 and 1000 ('Gigabit Ethernet') Mbits/second.
-==DIX Ethernet details==
+===DIX Ethernet details===
-The 48-bit physical address of the DIX Ethernet is known as the [[Media Access Control Address]] (short form: 'MAC Address' or just: 'MAC'), sometimes 'Ethernet Address' or 'Hardware Address' (the last is rather misleading if not explicitly used related to Ethernet networking).
+The 48-bit physical address used over the DIX Ethernet and successors is known as the [[Media Access Control Address]] (short form: 'MAC Address' or just: 'MAC'), sometimes 'Ethernet Address' or 'Hardware Address' (the last is rather misleading if not explicitly used related to Ethernet networking).
 ==Implementation==
@@ Line 43: / Line 50: @@
 ==Contemporary practise==
-Along with the issue above, the [[analog]] engineering of a very high speed, long, bus presents significant challenges. (This was one of the reasons for the initial popularity of rings, which are constructed of a number of [[point-point link]]s, inherently a simpler analog problem domain - and one susceptible to easy conversion to [[fiber optic]] technology.)
+Along with the issue above, the [[analog]] engineering of a very high speed, long, bus presents significant challenges. (This was one of the reasons for the initial popularity of rings, which are constructed of a number of independent (at the analog level) [[point-point link]]s, inherently a simpler analog problem domain - and one susceptible to easy conversion to [[fiber optic]] technology.)
 This had led to a gradual conversion to a wholly different kind of network structure in the internals of the network, where the attached stations cannot see it.
-The 'network' overall has been reduced to a series of two-node physical 'Ethernets', in which one end is the station, and the other is a 'hub' - a [[packet switch]] which acts as a [[bridge]]. A number of these hubs may be connected together (usually by two-node 'Ethernet' links). Thus, a typical 'Ethernet' is no longer a CSMA-CD bus, but rather a classic packet-switching network, with the hubs as the packet switches.
+The 'network' overall has been reduced to a series of two-node physical links, in which one end is the station, and the other is a 'hub' - a [[packet switch]] which acts as a [[bridge]]. A number of these hubs may be connected together (usually by similar two-node links). Thus, a typical 'Ethernet' is no longer a CSMA-CD bus, but rather a classic packet-switching network, with the hubs as the packet switches.
 ==See also==

← Older revision		Revision as of 20:02, 6 January 2025
Line 56:		Line 56:

	==External links==		==External links==
		+
		+	* [https://spectrum.ieee.org/ethernet-ieee-milestone Ethernet is Still Going Strong After 50 Years: The technology has become the standard LAN worldwide]

	===Experimental Ethernet===		===Experimental Ethernet===

@@ Line 73: / Line 73: @@
 * [http://www.mattmillman.com/projects/10base5 Building a 10BASE5 "Thick Ethernet" network] - A very good article about combining old and new Ethernet networking technology
 * [https://www.ibm.com/docs/en/zos/2.2.0?topic=internetworking-ethernet-dix-v2 Ethernet — DIX V2]
 * [https://lostintransit.se/2012/06/06/the-history-of-ethernet-dix-vs-802-3/ The history of Ethernet – DIX vs 802.3]
 [[Category: Networking]]
 [[Category: Xerox]]

@@ Line 56: / Line 56: @@
 ==External links==
 * [http://www.bitsavers.org/pdf/xerox/parc/techReports/CSL-75-7_Ethernet_Distributed_Packet_Switching_for_Local_Computer_Networks.pdf Ethernet: Distributed Packet Switching for Local Computer Networks] - paper describing the original Experimental Ethernet
 * [https://www.computerhistory.org/collections/catalog/X124.82E Experimental Ethernet transceiver] - at the [[Computer History Museum|CHM]], including a clamped-on vampire tap housing
 * [https://www.computerhistory.org/revolution/networking/19/381/2019 Alto Ethernet printed circuit board] - at the CHM
 * [http://gordonbell.azurewebsites.net/Digital/Ethernet%20Blue%20Book.pdf The Ethernet - A Local Area Network: Data Link Layer and Physical Layer Specifications]
 * [https://www.iana.org/assignments/ieee-802-numbers/ieee-802-numbers.xhtml IEEE 802 Numbers] - protocol numbers on Ethernet

@@ Line 61: / Line 61: @@
 * [https://www.computerhistory.org/revolution/networking/19/381/2019 Alto Ethernet printed circuit board] - at the CHM
 * [http://gordonbell.azurewebsites.net/Digital/Ethernet%20Blue%20Book.pdf The Ethernet - A Local Area Network: Data Link Layer and Physical Layer Specifications]
 * [http://gordonbell.azurewebsites.net/Ethernet_Seminar_Announcement_NYC_820210.PDF Ethernet Press Seminar] - announcement
 * [http://gordonbell.azurewebsites.net/Digital/Ethernet_announcement_820210c.pdf Why Digital is Committed to Ethernet for the Fifth Generation ] - Bell's seminar

@@ Line 21: / Line 21: @@
 The first two generations of Ethernet (at PARC, and the original DIX Ethernet) used [[coaxial cable]]; used as a [[transmission line]], it had good high-frequency propagation and [[noise]] resistance (see images above, and at the top).
-To connect an [[Ethernet transceiver]] (or 'station') to the network, a 'vampire tap' was used. A special connector was clamped to the cable; this connector had a threaded hole in it, with the center of the hole aligned with the center [[conductor]] of the cable. A cutting tool was then screwed in, which cut a hole through the [[ground]] layer (the woven metallic [[conductor]] layer in the images). This was then withdrawn, and the transceiver was screwed in; the transceiver's connector had a sharp pin which penetrated the [[insulation]] around the center conductor and made contact with it.
+To connect an [[Ethernet transceiver]] (or 'station') to the coaxial cable network, a 'vampire tap' was used. A special connector was clamped to the cable; this connector had a threaded hole in it, with the center of the hole aligned with the center [[conductor]] of the cable. A cutting tool was then screwed in, which cut a hole through the [[ground]] layer (the woven metallic [[conductor]] layer in the images). This was then withdrawn, and the transceiver was screwed in; the transceiver's connector had a sharp pin which penetrated the [[insulation]] around the center conductor and made contact with it.
 For a variety of reasons, this technology (called 10BASE5) was not the best approach for wide-scale service: it was replaced first with i) 10BASE2 (so-called 'thin net'), a smaller diameter coaxial cable with standard coaxial connectors pre-fabricated onto it; and then with ii) twisted-pair (10Base-T), using [[RJ11]] connectors.

@@ Line 1: / Line 1: @@
 [[Image:3MegEthernetCable.jpg|300px|right|thumb|3 Mbit/second Experimental Ethernet cable]]
-'''Ethernet''' is a family of computer networking technologies commonly used in [[local area network]]s (LANs), metropolitan area networks (MANs) and [[wide area network]]s (WANs).
+'''Ethernet''' is a family of computer [[data network]]ing technologies commonly used in [[local area network]]s (LANs), metropolitan area networks (MANs) and [[wide area network]]s (WANs).
-The first commercial version was introduced in 1980 by a consortium of [[Digital Equipment Corporation|DEC]], [[Intel]] and [[Xerox]] (hence its common label at the time, '''DIX Ethernet''',  from the initials of the partners); it was first openly standardized in 1983 as [[IEEE 802.3]].
+The first commercial version was a LAN introduced in 1980 by a consortium of [[Digital Equipment Corporation|DEC]], [[Intel]] and [[Xerox]] (hence its common label at the time, '''DIX Ethernet''',  from the initials of the partners); it was first openly standardized in 1983 as [[IEEE 802.3]].
-It originally operated at 10 Mbits/second; it has since been refined to support higher [[bit rate]]s and longer link distances (but see 'Parameter contention' below). Follow-on versions have been produced at 100 and 1000 ('Gigabit Ethernet') Mbits/second.
+That one originally operated at 10 Mbits/second; it has since been refined to support higher [[bit rate]]s and longer link distances (but see 'Parameter contention' below). Follow-on versions have been produced at 100 and 1000 ('Gigabit Ethernet') Mbits/second.
 It was based on, and inspired by, the '''Experimental Ethernet''', done at [[Xerox PARC]] to connect [[Xerox Alto|Altos]]; that operated at 3 Mbits/second.
@@ Line 19: / Line 19: @@
 [[Image:10MegEthernetCable.jpg|300px|right|thumb|Original 10 Mbit/second Ethernet cable]]
-The first two generations of Ethernet (at PARC, and the original XDI Ethernet) used [[coaxial cable]]; used as a [[transmission line]], it had good high-frequency propagation and [[noise]] resistance (see images above, and at the top).
+The first two generations of Ethernet (at PARC, and the original DIX Ethernet) used [[coaxial cable]]; used as a [[transmission line]], it had good high-frequency propagation and [[noise]] resistance (see images above, and at the top).
-To connect a [[Ethernet transceiver]] (or 'station') to the network, a 'vampire tap' was used. A special connector was clamped to the cable; this connector had a threaded hole in it, with the center of the hole aligned with the center conductor of the cable. A cutting tool was then screwed in, which cut a hole through the [[ground]] layer (the woven metallic [[conductor]] layer in the images). This was then withdrawn, and the transceiver was screwed in; the transceiver's connector had a sharp pin which penetrated the [[insulation]] around the center conductor and made contact with it.
+To connect an [[Ethernet transceiver]] (or 'station') to the network, a 'vampire tap' was used. A special connector was clamped to the cable; this connector had a threaded hole in it, with the center of the hole aligned with the center [[conductor]] of the cable. A cutting tool was then screwed in, which cut a hole through the [[ground]] layer (the woven metallic [[conductor]] layer in the images). This was then withdrawn, and the transceiver was screwed in; the transceiver's connector had a sharp pin which penetrated the [[insulation]] around the center conductor and made contact with it.
-For a variety of reasons, this technology (called 10BASE5) was not the best approach for wide-scale service: it was replaced first with i) 10BASE2 (so-called 'thin net'), a smaller diamater coaxial cable with standard coaxial connectors pre-fabricated onto it; and then with ii) twisted-pair (10Base-T), using [[RJ11]] connectors.
+For a variety of reasons, this technology (called 10BASE5) was not the best approach for wide-scale service: it was replaced first with i) 10BASE2 (so-called 'thin net'), a smaller diameter coaxial cable with standard coaxial connectors pre-fabricated onto it; and then with ii) twisted-pair (10Base-T), using [[RJ11]] connectors.
 ==Architecture==
-Originally, Ethernet was a [[Carrier-Sense Multiple Access with Collision Detection]] (CSMA-CD) bus (i.e. a shared broadcast channel on which all stations can hear any station which is transmitting).
+Originally, Ethernet was a [[Carrier-Sense Multiple Access with Collision Detection]] (CSMA-CD) [[bus]] (i.e. a shared [[broadcast]] channel on which all stations can hear any station which is transmitting).
 ===Parameter contention===
@@ Line 35: / Line 35: @@
 (I.e. the second station's message will only ''start'' to arrive at the first ''after'' the first's message has finished being sent, so no collision is detected there; and similarly at the second station.)
-To prevent this happening, the 10 Mbits/second spec called for a minimum message size, and a maximum physical size, so that one station's message (in the situation above) was ''guaranteed'' to start arriving at the other station before the other station finished its message - i..e. guaranteeing a detectable (at the transmitter) collision.
+To prevent this happening, the 10 Mbits/second spec called for a minimum message size, and a maximum physical size, so that one station's message (in the situation above) was ''guaranteed'' to start arriving at the other station before the other station finished its message - i.e. guaranteeing a detectable (at the transmitters) collision.
 However, this produces an unfortunate conflict between two parameters which it is desirable to increase; the speed, and maximum network size. If the network is made larger, then to guarantee that collisions will be detected, either i) the minimum message size must be made larger, or ii) the speed must be ''slowed''. Similarly, if the speed is raised, to keep the collision detection guarantee, either i) the minimum message size must be increased, or ii) the maximum size of the network must be ''reduced''.
@@ Line 43: / Line 43: @@
 ==Contemporary practise==
-Along with the issue above, the [[analog]] engineering of a very high speed, long, bus presents significant challenges. (This was one of the reasons for the initial popularity of rings, which are constructed of a number of point-point links, inherently a simpler analog problem domain - and one susceptible to easy conversion to [[fiber optic]] technology.)
+Along with the issue above, the [[analog]] engineering of a very high speed, long, bus presents significant challenges. (This was one of the reasons for the initial popularity of rings, which are constructed of a number of [[point-point link]]s, inherently a simpler analog problem domain - and one susceptible to easy conversion to [[fiber optic]] technology.)
 This had led to a gradual conversion to a wholly different kind of network structure in the internals of the network, where the attached stations cannot see it.
@@ Line 50: / Line 50: @@
 As in many similar cases, only the [[interface]] between the two parts (the station and the network) has been retained; the equipment on either side has been free to transform internally, and on one side it has done so in a major way.
 ==External links==
 * [http://www.bitsavers.org/pdf/xerox/parc/techReports/CSL-75-7_Ethernet_Distributed_Packet_Switching_for_Local_Computer_Networks.pdf Ethernet: Distributed Packet Switching for Local Computer Networks] - paper describing the original Experimental Ethernet
-* [https://www.computerhistory.org/revolution/networking/19/381/2019 Alto Ethernet printed circuit board] - at the [[Computer History Museum|CHM]]
+* [https://www.computerhistory.org/collections/catalog/X124.82E Experimental Ethernet transceiver] - at the [[Computer History Museum|CHM]], including a clamped-on vampire tap housing
 * [http://www.mattmillman.com/projects/10base5 Building a 10BASE5 "Thick Ethernet" network] - A very good article about combining old and new Ethernet networking technology
 * [https://www.ibm.com/docs/en/zos/2.2.0?topic=internetworking-ethernet-dix-v2 Ethernet — DIX V2]