This article highly notable figures in U.S. and Canadian national politics who were, or have been alleged by some to be, members of the Ku Klux Klan prior to their public careers. No one serving as a federal judge or senior official in the 1920s is known to have belonged to the second KKK in that period.

Individual cases
A former Klansman to rise to national prominence was the Democratic Senator and later Supreme Court Justice Hugo Black who, early in his political career, defended one of the group's members charged with the assassination of Father James Coyle, an Alabama Catholic priest. Black obtained a "not guilty" verdict from a Klan-controlled jury. Later Black repudiated the Klan and championed a conflicting conception of civil rights.

Hugo Black
In 1924, Harry Truman was a judge in Jackson County, Missouri, which includes Kansas City. Truman was up for reelection, and his friends Edgar Hinde and Spencer Salisbury advised him to join the Klan. The Klan was politically powerful in Jackson County, and two of Truman's opponents in the Democratic primary had Klan support. Truman refused at first, but paid the Klan's $10 membership fee, and a meeting with a Klan officer was arranged. It is also possible to interpret it as a young politician's opportunistic attempt to get ahead. The incident was clearly entwined with the intricacies of machine politics, and may also be seen as an indication of Truman's long evolution in his outlook on race relations.

Robert Byrd
It has been alleged that United States President Warren G. Harding was inducted into the Ku Klux Klan during his administration. The evidence is highly disputed.

Warren Harding
Wyn Craig Wade states Harding's membership as fact and gives a detailed account of a secret swearing-in ceremony in the White House, but bases this claim on a private communication in 1985 from journalist Stetson Kennedy. Kennedy, in turn had, along with Elizabeth Gardner, tape recorded the "late 1940s" deathbed confession of former Imperial Klokard Alton Young, who claimed to have been a member of the "Presidential Induction Team" as Young was dying in a New Jersey Hospital. Young also claimed to have repudiated racism on his deathbed.
Simmons' ultimate vindication came when President Warren G. Harding agreed to be sworn in as a member of the Ku Klux Klan. A five-man "Imperial induction team," headed by Simmons, conducted the ceremony in the Green Room of the White House. Members of the team were so nervous that they forgot their Bible in the car, so Harding had to send for the White House Bible. In consideration of his status, Harding was permitted to rest his elbow on the desk, as he knelt on the floor during the long oath taking. Afterward, the President appreciatively gave members of the team War Department license tags that allowed them to run red lights all across the nation.
Wade also states that "This matter was a major issue in letters sent to Coolidge during the 1924 election", and gives a reference to "Case File 28, Calvin Coolidge papers, Manuscript Division, Library of Congress." In this file there is a letter from Wizard Edward Young Clarke to President Calvin Coolidge on 27 December 1923, charging Wizard Hiram W. Evens with trying to turn the Klan into a "cheap political machine". "It [the Klan] was to be an organization designed to up-build and develop spirituality, morality, and physically the Protestant white man of America."

Evidence for Harding's membership
In their book Freakonomics, economist Stephen J. Dubner and journalist Steven D. Levitt write of their visit to Stetson Kennedy's Florida home, and Harding's possible affiliation with the Klan. However, in a 8 January 2006 article for the New York Times Magazine, Dubner and Levitt wrote an expose of Stetson Kennedy, ("Hoodwinked" pp 26-28) claiming that Kennedy had long systematically exaggerated and misrepresented his work and "hoodwinked" his readers for over 50 years. While nothing in the article specifically dealt with the claim that Harding and the Klan were affiliated with one and other, the implication was that Kennedy's claims and conclusions should be reviewed for accuracy, rather than being accepted at full face value.
Primary source material on file at the Ohio Historical Society in Columbus — which holds more than linear feet of Harding papers from his Presidency does not contain evidence of Harding's alleged membership in the Klan.
Primary source material on file at the Marion County (Ohio) Historical Society (Warren G. Harding Collection) also does not confirm or indicate any involvement in the Klan, nor support the idea of Harding's alleged Klan membership.
Harding was the first American President to publicly denounce lynching and did so in a landmark 21 October 1921 speech in Birmingham, Alabama, which was covered in the national press. Harding also vigorously supported an anti-lynching bill in Congress during his term in the White House. While the bill was defeated in the Senate, such activities would be in direct conflict with Klan membership.
The Site Administrator of the Harding Home Museum (Ohio Historical Society property) in Marion, Ohio, draws a relationship between Harding's alleged Klan activities directly to the rumor-mill stirred up after the President died in 1923 and Mrs. Harding in 1924. (Such rumors also alluded to the President's knowledge of the Teapot Dome scandal, which involved Albert Fall, but not the President.)
Furthermore, Harding's ability to join the Klan is dubious given the numerous rumors that swirled around his supposed mixed race heritage. This theory, promoted by William Estabrook Chancellor, a one-time history professor at the College of Wooster and noted racist, was a direct attempt to keep Harding from securing the Presidency. If true and tested, Chancellor's book, published shortly before the 1920 Presidential election, would have been proof positive that Harding violated the Klan's "one drop rule" which qualified people as being "colored" if they had one drop of Negro blood in their veins.
In his book, The Strange Deaths of President Harding, historian Robert Ferrell Ph.D. claims to have been unable to find any records of any such "ceremony" in which Harding was brought into the Klan in the White House. Also, John Dean, in his 2004 book Warren Harding (edited by Arthur M. Schlesinger), also could find no proof of Klan membership or activity on the part of the 29th President to indicate support of the Klan.
Review of the personal records of Harding's Personal White House Secretary, George Christian Jr., also do not support the contention that Harding received members of the Klan while in office. Appointment books maintained in the White House, detailing President Harding's daily schedules, do not show any such event (but document the visit by members of the Masonic Rite).
In addition to the above points, the 1920 Republican Party platform, which essentially expressed Harding's political philosophy, outright calls for Congress to pass laws combatting lynching.
Anthony also details Harding's induction into the Tall Cedars of Lebanon, a Shrine organization, during the convention week (making note of the conical hat used by the Tall Cedars in the ceremony); Anthony writes that he feels that the charges made by Grand Wizard Alton Young (reported by Wyn Craig Wade in 1985) against Harding were in "retaliation for the Shrine speech and another anti-bigotry speech made by Harding at the dedication of the Alexander Hamilton statue at the Treasury Building" in the previous month of May 1923.
In 2005, The Straight Dope presented a summary [16] of many of these arguments against Harding's membership and added speculation about Harding's motives as further evidence that he would not have joined (i.e. that it while it might have been politically expedient for him to join the KKK in public to do it in private made no sense).

Evidence against Harding's membership or support of the KKK
Wyn Craig Wade has asserted that Edward D. White, the chief justice of the U.S. Supreme Court from 1910 to 1921, told Thomas Dixon "I was a member of the Klan" at the 1915 White House screening of The Birth of a Nation. No evidence has been found that corroborates his alleged admission. White, in any event, never joined the second KKK. He did, however, fight in the Confederate Army during the American Civil War.

Others

^  Wade, 1987.
^  "Woody Guthrie: Natural born anti-fascist" by Kennedy, retrieved 9 September 2005.
^  Wade, 1987, pp. 165, 477.
^  Republican Party Platform of 1920 (available from the American Presidency Project of the University of California, Santa Barbara).
^  Anthony, pp. 412-413.
^  McCullough, p. 164.
^  Steinberg, 1962. Salisbury was a war buddy and former business partner of Truman's. Salisbury states that Truman attempted "to give Jim Pendergast control of [their] business." Salisbury began attacking Truman's patrons, the Pendergast machine, for corruption, and Truman retaliated by telegramming the Federal Home Loan Bank system about Salisbury, leading to Salisbury's conviction for filing a false affidavit. Salisbury contradicts Hinde's statement that the meeting at the Hotel Baltimore was one-on-one, naming at least six individuals who were present. Salisbury states that at the meeting, Truman had to receive a special dispensation to join, because his grandfather Solomon had been a Jew; however, Solomon was not a Jew, and the rumor of Truman's Jewish ancestry was only spread later, by the Klan, once the political lines had been drawn so that Truman was the Klan's enemy.
^  Wade, 1987, p. 196, gives essentially this version of the events, but implies that the meeting was a regular Klan meeting, rather than an individual meeting between Truman and a Klan organizer. An interview with Hinde at the Truman Library's web site ("Oral History Interview with Edgar G. Hinde" by James R. Fuchs, 15 March 1962, retrieved June 26, 2005) portrays it as a one-on-one meeting at the Hotel Baltimore with a Klan organizer named Jones. Truman's biography, written by his daughter (Truman, 1973), agrees with Hinde's version, but does not mention the $10 initiation fee; the same biography reproduces a telegram from O.L. Chrisman stating that reporters from the Hearst papers had questioned him about Truman's past with the Klan, and that he had seen Truman at a Klan meeting, but that "if he ever became a member of the Klan I did not know it."
^  McCullough, 1992.
^  Truman, 1973.
^  Truman, 1973; McCullough, 1992, p. 170.
^  Hamby, 1995.
^  McCullough notes this extensively in his Pulitzer Prize-winning biography of Truman. While Truman had been raised in a family with Southern and Confederate leanings, he still said that he believed "in the brotherhood of all men before the law" (McCullough, p. 247). His work on civil rights was politically damaging but extensive nonetheless.
^  "A Senator's Shame" by Eric Pianin in the Washington Post, 19 June 2005
^  NAACP Civil Rights Federal Legislative Report Card: 108th Congress
^  CNN: "Top Senate Democrat apologizes for slur"
^  Wade, 1987. Cited in Bombingham by Mark Gado, Chapter 2: "The Klan"

Coordinates: 25°24′N 94°05′E / 25.4, 94.08 Nagaland pronunciation (help·info) is a hill state located in the far northeastern part of India. It borders the state of Assam to the west, Arunachal Pradesh and part of Assam to the north, Myanmar to the east and Manipur to the south. The state capital is Kohima, and the largest city is Dimapur. With a population of nearly two million people, it has a total area of 16,579 km. - making it one of the smallest states of India.

History
Nagaland is largely a mountainous state. The Naga Hills rise from the Brahmaputra Valley in Assam to about 2,000 feet and rise further to the southeast, as high as 6,000 feet. Mount Saramati at an elevation of 12,552level is the state's highest peak - this is where the Naga Hills merge with the Patkai Range in Myanmar. Rivers such as the Doyang and Dhiku to the north, the Barak river in the southwest and the Chindwin river of Myanmar in the southeast, dissect the entire state.
Nagaland is rich in flora and fauna. About one-sixth of Nagaland is under the cover of tropical and sub-tropical evergreen forests - including palms, bamboo and rattan as well as timber and mahogany forests. While some forest areas have been cleared for jhum - cultivation - many scrub forests, high grass, reeds and secondary dogs, pangolins, porcupines, elephants, leopards, bears, many species of monkeys, sambar, deers, oxen and buffaloes thrive across the state's forests. The Great Indian Hornbill is one of the most famous birds found in the state.
Nagaland has a largely monsoon climate with high humidity levels. Annual rainfall averages around 70-100 inches - concentrated in the months of May to September. Temperatures range from 70 degrees to 104 degrees fahrenheit. In winter, temperatures don't generally drop below 39 degrees fahrenheit, but frost is common at high elevations.

Geography and climate
The tribes of Nagaland are Lothas, Angami, Ao, Chakhesang , Chang, Khiamniungan, Konyak, Phom, Pochury, Rengma, Sumi, Sangtam, Yimchungru, Tangkhul, Zeliang of which the Angamis, Aos, Lothas and Sumis are the largest Naga tribes. Tribe and Clan traditions and loyalties plays an important part in the life of Nagas. Weaving is a traditional art handed down through generations in Nagaland. Each of the major tribes has its own unique designs and colors, producing shawls, shoulder bags, decorative spears, table mats, wood carvings and bamboo works. Tribal dances of the Nagas give an insight into the inborn reticence of the people. War dances and dances belonging to distinctive tribes are a major art form in Nagaland. Some of these are Moatsu, Sekrenyi, Tuluni and Tokhu Emong. More than 80% of the people live in rural areas. Nagas lack a common written language, except the Tenyidie language and speak 60 different dialects belonging to the Sino-Tibetan family of languages. Nagamese, a variant language form of Assamese and Hindi is the most widely spoken language. One interesting part is every tribe has their own mother tongue language and these tribes communicate with each other in Nagamese. As such Nagamese is not a mother tongue of any of the tribes and nor is it a written language. English, the official state language is widely spoken in official circles and is the medium for education in Nagaland.

Culture and people
Christianity is the predominant religion of Nagaland. The census of 2001 recorded the state's Christian population at 1,790,349 (90.02% of the state's population), making it one of the three Christian-majority states in India, and the only state where Christians form 90% of the population. The state has a very high church attendance rate in both urban and rural areas. The largest of Asia's churches dominate the skylines of Kohima, Dimapur and Mokokchung. Among Christians, Baptists are the predominant group constituting more than 75% of the state's population.
Nagaland is known as "The most Baptist state in the world". The state's population is 1.988 million (2001 census), out of which 90.02% are Christians. 75% of the state's population profess the Baptist faith, thus making it more Baptist than Mississippi, where 52% of its population is Baptist.Catholics, Revivalists, and Pentecostals are the other Christian denomination numbers. Catholics are found in significant numbers in parts of Wokha district as also in the urban areas of Kohima and Dimapur. Hindus and Muslims constitute the non-Naga populations of the state and form 7.7% and 1.8% of the population. A small minority, less than 0.3% still practise the traditional religions and are mainly concentrated in Peren and the Eastern districts.

Religion

• "Gateway of Nagaland", " The Commercial Hub(of Nagaland)", "Melting Pot" - Dimapur
  "Highland City", "Misty City" - Kohima
  "Cultural capital (of Nagaland)", "Picture perfect city", "Aomolung", "Nagaland's trendsetter"- Mokokchung
  "Rice Bowls of Nagaland"- Jalukie valley; Tsurang-Changki valley
  "Serpentine town"- Tuensang Sobriquets/ Nicknames
  The Governor of Nagaland is the constitutional head of state, representative of the President of India. He possesses largely ceremonial responsibilities. A 60-member Vidhan Sabha is the state of ministers, led by a Chief minister - all elected members of legislature - forms the government executive. Unlike most Indian states, Nagaland has been granted a great degree of state autonomy, as well as special powers and autonomy for Naga tribes to conduct their own affairs. Each tribe has a hierarchy of councils - at the village, range and tribal levels dealing with local disputes. There is a special regional council for the Tuensang district, elected by the tribes of the area.
  The state is divided into eleven districts. Mokokchung District is Nagaland's Most Advanced District.
  
  Dimapur District
  Kiphire District
  Kohima District
  Longleng District
  Mokokchung District
  Mon District
  Peren District
  Phek District
  Tuensang District
  Wokha District
  Zunheboto District
  Chumukedima(Dimapur)
  Kiphire
  Kohima
  Longleng
  Mokokchung
  Mon
  Peren
  Phek
  Tuensang
  Wokha
  Zunheboto Administration
  
  Urban centres
  
  Dimapur
  Kohima
  Mokokchung
  Tuensang
  Wokha
  Mon Major cities and towns
  There are four urban agglomeration areas with population of more than 40,000 in the state which are:
  
  Major (Non-District Headquarter) towns
  
  Economy
  This is a chart of trend of gross state domestic product of Nagaland at market prices estimated by Ministry of Statistics and Programme Implementation with figures in millions of Indian Rupees.
  Nagaland's gross state domestic product for 2004 is estimated at $1.4 billion in current prices.
  Agriculture is the most important economic activity in Nagaland, with more than 90% of the population employed crops include rice, corn, millets, pulses, tobacco, oilseeds, sugarcane, potatoes and fibres. However, Nagaland still depends on the import of food supplies from other states. The widespread practice of jhum - clearing for cultivation - has led to soil erosion and loss of fertility. Only the Angami and Chakesang tribes in the Kohima district use terracing and irrigation techniques. Forestry is also an important source of income. Cottage industries such as weaving, woodwork and pottery are also an important source of revenue. Tourism is important, but largely limited owing to the state's geographic isolation and political instability in recent years.
  
  Macro-economic trend
  The railway network in the state is minimal . The length of broad gauge lines is 7.63 km, while that of the metre gauge lines is only 5.22 km. The length of National Highway roads is 365.38 km and state roads is 1094 km. The only airport in the state is Dimapur.
  
  Transportation
  Railway: North East Frontier Railway
  [Data Source: N. F. Railway, CME Office, Guwahati-781011]
  
  Broad Gauge-7.63 km
  Metre Gauge-5.22 km
  Total-12.85km Highways
  1. Nagaland Post - http://www.nagalandpost.com
  2. The North East Herald - http://thenortheastherald.com/
  3. Nagaland Page - http://www.nagalandpage.co.in/ 4. The Eastern Mirror
  5. The Morung Express - http://www.morungexpress.com ,
  6. Tir Yimyim (in Ao language)- http://www.tiryimyim.com .
  7. Ao Milen (in Ao language}. 8. Capi (in Tenyidie language). 9. Tenyi Ralha (in Tenyidie language).
  

Pontiac or Obwandiyag (c. 1720 – April 20, 1769), was an Ottawa leader who became famous for his role in Pontiac's Rebellion (1763–1766), an American Indian struggle against the British military occupation of the Great Lakes region following the British victory in the French and Indian War. Historians disagree about Pontiac's importance in the war that bears his name. Nineteenth century accounts portrayed him as the mastermind and leader of the revolt, while some subsequent interpretations have depicted him as a local leader with limited overall influence.
The war began in May 1763 when Pontiac and 300 followers attempted to take Fort Detroit by surprise. His plan foiled, Pontiac laid siege to the fort, and was eventually joined by more than 900 warriors from a half-dozen tribes. Meanwhile, messengers spread the word of the Pontiac's actions, and the war expanded far beyond Detroit. In July 1763, Pontiac defeated a British detachment at the Battle of Bloody Run, but he was unable to capture the fort. In October he lifted the siege and withdrew to the Illinois country.
Although Pontiac's influence had declined around Detroit because of the unsuccessful siege, he gained stature in the Illinois and Wabash country as he continued to encourage resistance to the British. Seeking to end the war, British officials made Pontiac the focus of their diplomatic efforts. In July 1766, Pontiac made peace with British Superintendent of Indian Affairs Sir William Johnson. The attention which the British paid to Pontiac created resentment among other Indian leaders, particularly because Pontiac claimed far greater authority than he actually possessed. Increasingly ostracized, in 1769 he was assassinated by a Peoria Indian.

Early years

Main articles: Pontiac's Rebellion and Siege of Fort Detroit

The Lagrangian points (pronounced [ləˈgɹɒɲ.dʒi.ən] or [laˈgʀɑ̃.ʒjɑ̃]); (also Lagrange point, L-point, or libration point), are the five positions in an orbital configuration where a small object affected only by gravity can theoretically be stationary relative to two larger objects (such as a satellite with respect to the Earth and Moon). The Lagrange points mark positions where the combined gravitational pull of the two large masses provides precisely the centripetal force required to rotate with them. They are analogous to geosynchronous orbits in that they allow an object to be in a "fixed" position in space rather than an orbit in which its relative position changes continuously.
A more precise but technical definition is that the Lagrangian points are the stationary solutions of the circular restricted three-body problem. For example, given two massive bodies in circular orbits around their common center of mass, there are five positions in space where a third body, of comparatively negligible mass, could be placed which would then maintain its position relative to the two massive bodies. As seen in a rotating reference frame with the same period as the two co-orbiting bodies, the gravitational fields of two massive bodies combined with the centrifugal force are in balance at the Lagrangian points, allowing the third body to be stationary with respect to the first two bodies.

History and concepts
The five Lagrangian points are labeled and defined as follows:

The Lagrangian points
The L₁ point lies on the line defined by the two large masses M₁ and M₂, and between them. It is the most intuitively understood of the Lagrangian points: the one where the gravitational attractions of the two other objects effectively cancel each other out.
Example: An object which orbits the Sun more closely than the Earth would normally have a shorter orbital period than the Earth, but that ignores the effect of the Earth's own gravitational pull. If the object is directly between the Earth and the Sun, then the effect of the Earth's gravity is to weaken the force pulling the object towards the Sun, and therefore increase the orbital period of the object. The closer to Earth the object is, the greater this effect is. At the L₁ point, the orbital period of the object becomes exactly equal to the Earth's orbital period.
The Sun–Earth L₁ is ideal for making observations of the Sun. Objects here are never shadowed by the Earth or the Moon. The Solar and Heliospheric Observatory (SOHO) is stationed in a Halo orbit at L₁, and the Advanced Composition Explorer (ACE) is in a Lissajous orbit, also at the L₁ point. The Earth–Moon L₁ allows easy access to lunar and earth orbits with minimal change in velocity, and would be ideal for a half-way manned space station intended to help transport cargo and personnel to the Moon and back.

L1
The L₂ point lies on the line defined by the two large masses, beyond the smaller of the two. Here, the gravitational forces of the two large masses balance the centrifugal force on the smaller mass.
Example: On the side of the Earth away from the Sun, the orbital period of an object would normally be greater than that of the Earth. The extra pull of the Earth's gravity decreases the orbital period of the object, and at the L₂ point that orbital period becomes equal to the Earth's.
The Sun–Earth L₂ is a good spot for space-based observatories. Because an object around L₂ will maintain the same orientation with respect to the Sun and Earth, shielding and calibration are much simpler. The Wilkinson Microwave Anisotropy Probe is already in orbit around the Sun–Earth L₂. The future Herschel Space Observatory, Gaia probe, and James Webb Space Telescope will be placed at the Sun–Earth L₂. Earth–Moon L₂ would be a good location for a communications satellite covering the Moon's far side.
If the mass of the smaller object (M₂) is much smaller than the mass of the larger object (M₁) then L₁ and L₂ are at approximately equal distances r from the smaller object, equal to the radius of the Hill sphere, given by:
where R is the distance between the two bodies.
This distance can be described as being such that the orbital period, corresponding to a circular orbit with this distance as radius around M₂ in the absence of M₁, is that of M₂ around M₁, divided by .
Examples:

Sun and Earth: 1,500,000 km from the Earth
Earth and Moon: 61,500 km from the Moon L2
The L₃ point lies on the line defined by the two large masses, beyond the larger of the two.
Example: L₃ in the Sun–Earth system exists on the opposite side of the Sun, a little outside the Earth's orbit but slightly closer to the Sun than the Earth is. Here, the combined pull of the Earth and Sun again causes the object to orbit with the same period as the Earth. The Sun–Earth L₃ point was a popular place to put a "Counter-Earth" in pulp science fiction and comic books — though of course, once space based observation was possible via satellites and probes, it was shown to hold no such object. In actual fact, Sun–Earth L₃ is highly unstable, because the gravitational forces of the other planets outweigh that of the Earth (Venus, for example, comes within 0.3 AU of L₃ every 20 months).

L3
The L₄ and L₅ points lie at the third corners of the two equilateral triangles in the plane of orbit whose common base is the line between the centres of the two masses, such that the point lies behind (L₅) or ahead of (L₄) the smaller mass with regard to its orbit around the larger mass.
The reason these points are in balance is that, at L₄ and L₅, the distances to the two masses are equal. Accordingly, the gravitational forces from the two massive bodies are in the same ratio as the masses of the two bodies, and so the resultant force acts through the barycentre of the system; additionally, the geometry of the triangle ensures that the resultant acceleration is to the distance from the barycentre in the same ratio as for the two massive bodies. The barycentre being both the centre of mass and centre of rotation of the system, this resultant force is exactly that required to keep a body at the Lagrange point in orbital equilibrium with the rest of the system. (Indeed, the third body need not have negligible mass; the general triangular configuration was discovered by Lagrange in work on the 3-body problem.)
L₄ and L₅ are sometimes called triangular Lagrange points or Trojan points. The name Trojan points comes from the Trojan asteroids at the Sun–Jupiter L₄ and L₅ points, which themselves are named after characters from Homer's Iliad (the legendary siege of Troy). Asteroids at the L₄ point, which leads Jupiter, are referred to as the 'Greek camp', while at the L₅ point they are referred to as the 'Trojan camp'. These asteroids are (largely) named after characters from the respective sides of the war.
Examples:
The Sun–Earth L₄ and L₅ points lie 60° ahead of and 60° behind the Earth as it orbits the Sun. They contain interplanetary dust.
The Earth–Moon L₄ and L₅ points lie 60° ahead of and 60° behind the Moon as it orbits the Earth. They also contain interplanetary dust in what is called Kordylewski clouds.
The Sun–Jupiter L₄ and L₅ points are occupied by the Trojan asteroids.
Neptune has Trojan Kuiper Belt Objects at its L₄ and L₅ points.
Saturn's moon Tethys has two much smaller satellites at its L₄ and L₅ points named Telesto and Calypso, respectively.
Saturn's moon Dione has smaller moons Helene and Polydeuces at its L₄ and L₅ points, respectively.
The giant impact hypothesis suggests that an object named Theia formed at L₄ or L₅ and crashed into the Earth after its orbit destabilized, forming the moon. Stability
This section non-mathematically (intuitively) explains the five Lagrangian points using the Earth–Moon system.
Lagrangian points L₂ through L₅ only exist in rotating systems, as in the monthly orbiting of the Moon about the Earth. At these points, an outward (fictitious, as explained below) centrifugal force is balanced by the two radially attractive gravitational forces of the Moon and Earth.
Imagine using your hand to spin a weight at the end of a string. Your hand will feel an outward radial force in the direction of the weight. However, if you release the string, the weight does not travel radially outward in the direction of the sensed force. Instead, the weight travels tangentially to the circle, in the direction of spin at the time the string was released. This is why this force is called "fictitious". This same outward force is present in the Earth–Moon system, where the role of the string is played by the summed (or net) effect of the two attractive gravities, and the weight is an asteroid or science satellite. The Earth–Moon system rotates about a barycenter. Because the Earth is much heavier, this barycenter is located about a thousand miles below the Earth's surface, in the direction of the Moon (three thousand miles above the Earth's center, see Earth, Moon, and barycenter). Any object gravitationally held by the rotating Earth–Moon system will sense this (fictitious but calculably real) outward radial force away from the barycenter, in the same way your hand feels the outward pull of the string.
Unlike the other Lagrangian points, L₁ would exist even in a non-rotating (static or inertial) system. Rotation slightly pushes L₁ away from the (heavier) Earth towards the (lighter) Moon. L₁ is slightly unstable (see stability above) because drifting towards the Moon or Earth increases one gravitational attraction while decreasing the other, causing more drift.
At Lagrangian points L₂, L₃, L₄, and L₅, a satellite feels an outward centrifugal force, away from the barycenter, that exactly balances the attractive gravity of the Earth and Moon. L₂ and L₃ are slightly unstable because small changes in satellite position more strongly affect gravity than the balancing centrifugal force. Stability at L₄ and L₅ depends crucially on the satellite being pulled in three different directions, namely the outward centrifugal force away from the barycenter, balancing the inward gravitational forces towards the Moon and Earth.

Intuitive explanation
The Lagrangian point orbits have unique characteristics that have made them a good choice for performing some kinds of missions. NASA has operated a number of spacecraft in orbit around the Sun–Earth L₁ and L₂ points, including
ESA's Herschel Space Observatory (formerly called Far Infrared and Sub-millimetre Telescope or FIRST) in 2008 and the James Webb Space Telescope are also planned to be placed in orbit around L₂. ESA's Planck satellite planned for launch in 2008 will be placed in orbit around L₂.
The L5 Society was a precursor of the National Space Society, and promoted the possibility of establishing a colony and manufacturing facility in orbit around the L₄ or L₅ points in the Earth–Moon system (see Space colonization).
The Earth–Moon L₂ point has been proposed as a location for a communication satellite covering the far side of the Moon. NASA TN_D-4059
The Deep Space Climate Observatory was intended to be positioned at L₁, but has been put into indefinite storage after being built.

Lagrangian point missions
In the Sun–Jupiter system several thousand asteroids, collectively referred to as Trojan asteroids, are in orbits around the Sun–Jupiter L₄ and L₅ points. Recent observations suggest that the Sun–Neptune L₄ and L₅ points, known as the Neptune Trojans, may be very thickly populated, containing large bodies an order of magnitude more numerous than the Jupiter Trojans. Other bodies can be found in the Sun–Mars and Saturn–Saturnian satellite systems. There are no known large bodies in the Sun–Earth system's Trojan points, but clouds of dust surrounding the L₄ and L₅ points were discovered in the 1950s. Clouds of dust, called Kordylewski clouds, even fainter than the notoriously weak gegenschein, are also present in the L₄ and L₅ of the Earth–Moon system.
The Saturnian moon Tethys has two smaller moons in its L₄ and L₅ points, Telesto and Calypso. The Saturnian moon Dione also has two Lagrangian co-orbitals, Helene at its L₄ point and Polydeuces at L₅. The moons wander azimuthally about the Lagrangian points, with Polydeuces describing the largest deviations, moving up to 32 degrees away from the Saturn–Dione L₅ point. Tethys and Dione are hundreds of times more massive than their "escorts" (see the moons' articles for exact diameter figures; masses are not known in several cases), and Saturn is far more massive still, which makes the overall system stable.

Natural examples
The Earth's companion object 3753 Cruithne is in a relationship with the Earth which is somewhat Trojan-like, but different from a true Trojan. This asteroid occupies one of two regular solar orbits, one of them slightly smaller and faster than the Earth's orbit, and the other slightly larger and slower. The asteroid periodically alternates between these two orbits due to close encounters with Earth. When the asteroid is in the smaller, faster orbit and approaches the Earth, it loses orbital energy to the Earth and moves into the larger, slower orbit. It then falls farther and farther behind the Earth, and eventually Earth approaches it from the other direction. Then the asteroid gains orbital energy from the Earth, and moves back into the smaller orbit, thus beginning the cycle anew. The cycle has no noticeable impact on the length of the year, because Earth's mass is over 20 billion (2 × 10) times more than 3753 Cruithne.
Epimetheus and Janus, satellites of Saturn, have a similar relationship, though they are of similar masses and so actually exchange orbits with each other periodically. (Janus is roughly 4 times more massive, but still light enough for its orbit to be altered.) Another similar configuration is known as orbital resonance, in which orbiting bodies tend to have periods of a simple integer ratio, due to their interaction.

Other co-orbitals
The Lagrange points are mentioned in science fiction from time to time (most often hard science fiction), but, due to the general lack of public familiarity with them, they are rarely used as a plot device or reference.

In fiction

The L5 Lagrange point is mentioned in L5: First City in Space, an early IMAX 3D movie.
In William Gibson's novel Neuromancer, much of the action takes place in the L5 "archipelago", the location of many space stations.
The planet Troas in the stories "Sucker Bait" by Isaac Asimov and "Question and Answer" by Poul Anderson was located in the L₅ point of a fictional binary star system.
The space station Babylon 5 is described to be located "at the L-5 point in a binary star system between a moon and a barren, lifeless planet." [1]
In Hideo Kojima's video game Policenauts, the setting of the game, an O'Neill model space colony, is located at the L5 Lagrange point.
The genetically engineered humans or "Coordinators" of Mobile Suit Gundam Seed settle in L5 living in hour glass shaped colonies known as PLANTs L5

In Larry Niven's novels The Integral Trees and The Smoke Ring, the L4 and L5 points of the Smoke Ring (a ring of breathable air and plant life orbiting a neutron star) have become gathering places for masses of water, living things, and human settlers.
The eponymous interplanetary relay station in George O. Smith's "Venus Equilateral" stories was located in the L₄ point of the Sun–Venus system. L4

See also: Counter-Earth
In Peter F Hamilton's Night's Dawn Trilogy, a ZTT jump drive cannot be used in a strong gravitational field. In the first book of the trilogy, The Reality Dysfunction, the main characters cannot escape from a gas giant's gravity well before their pursuers catch up with them. Instead, they race to the Lagrange point between the gas giant and one of its moons in order to activate their drive. Successful execution of this untried and reckless maneuver gains captain Joshua Calvert the nickname "LaGrange" Calvert. In the second book The Neutronium Alchemist, a visit is paid to the supposed home planet of the Kiint, Jobis, which features three moons orbiting the Lagrange One point, rotating around a common centre.
In the third season of the TV series Lexx, the planets Fire and Water are found to reside in Earth's L3 point.
John Norman's Gor series takes place on a counter earth. L3

See also: Lilith (hypothetical moon)
In the TV series Quatermass II, the hostile aliens live on a small asteroid "no more than half a mile across" at a "theoretical point of equilibrium" on the dark side of the Earth, although neither L2 or Lagrange are mentioned by name (the term "Bieber Variation" is used instead).
In the Star Trek: The Next Generation episode, "The Survivors", the Enterprise is surprised by an enemy ship that had been hiding in a Lagrange point.
In the manga series Battle Angel Alita: Last Order, the ex-colony ship turned space station Leviathan 1 is at the L2 point in the Earth/Moon system.
In John Varleys book Wizard a religious group called the Coven set up a habitat at L2 to make themselves as remote as possible from the earth. L2 later slowly deteriorates into the space version of an unorganized shantytown as anyone with enough cash can set up home there. "L2 became known as Sargasso Point to the pilots who carefully avoided it; those who had to travel through it called it the Pinball Machine, and they didn't smile." L2

In Arthur Clarke and Stephen Baxter's novel Sunstorm, the L1 point plays a crucial role in the building of a shield that has the purpose of saving Earth from a storm of energy from the Sun.
In the Xbox video game Halo: Combat Evolved (2001) and sequel Halo 2 (2004), Halo Megastructures play key locations throughout the games. In Halo: CE and Halo 2, the Halo structures are in L1 Lagrange points between the Gas Giants (and a moon) Threshold and Substance, respectively.
In the Hugo Award-winning novel A Deepness in the Sky by Vernor Vinge, a temporary human habitat is built at the L1 point between the planet Arachna and its primary star, a highly variable dwarf called the On/Off Star. Unspecified Lagrange points

Gesellschaft mit beschränkter Haftung (GmbH) is a type of legal entity very common in Germany (where it was created in 1892), Austria (adopted in 1906), Switzerland, and other Central European countries. It is governed by a federal law called "GmbH-Gesetz" (GmbH law) [1] [2].
Literally translating as company with limited liability, the concept mit beschränkter Haftung inspired the creation of the limited liability company form in other countries. The name of the GmbH form emphasizes the fact that the owners (Gesellschafter, also known as members) of the entity are not personally liable for the company's debts. Other variations include mbH (used when the term Gesellschaft is part of the company name itself), and gGmbH (gemeinnützige GmbH) for non-profit companies.
The GmbH has become the most widespread company form in Germany, since the AG (Aktiengesellschaft), the other major company form corresponding to a stock corporation, was until recently much more complicated to form and operate.
It is widely accepted that a GmbH is formed in three stages: the founding association, which is regarded as a private partnership with full liability of the founding partners/members; the founded company (often qualified with "i.G.", meaning "in Gründung"); and the fully registered GmbH. Only the registration of the company in the Commercial Register (Handelsregister) provides the GmbH with its full legal status.
The founding act and the articles of association have to be notarized. The GmbH law outlines the minimum content of the articles of association, but it is quite common to have a wide range of additional rules in the articles.
Under German law, the GmbH must have a minimum founding capital of €25,000, of which 25% but at least €12,500 has to be contributed by its members (when the GmbH has only one member the law is even stricter regarding the required capital contribution). A supervisory board (Aufsichtsrat) is required if the company has more than 500 employees, otherwise the company is run only by the managing directors (Geschäftsführer) who have unrestricted proxy for the company. The members acting collectively may restrict the powers of the managing directors by giving them binding orders. In most cases, the articles of association list the business activities for which the directors must obtain prior consent from the members. Under German law, a violation of these duties by a managing director will not affect the validity of a contract with a third party, but the GmbH may hold the managing director in question liable for damages.
Because a legal entity with liability limited to the contributed capital was regarded in the 19th century as something dangerous, German law has many restrictions unknown to common law systems. A number of business transactions have to be notarized, such as transfer of shares, issuing of stock, and amendments to the articles of association. Many of those measures have to be filed with the company registry where they are checked by special judges or other judicial officers. This can be a tiresome and time-consuming process as in most cases the desired measures are only legally valid when entered into the registry. Because there is no central company registry in Germany but rather several hundred connected to regional courts, the administration of the law can be rather different between German states.

DHCP · DNS · FTP · Gopher · HTTP · IMAP4 · IRC · NNTP · XMPP · POP3 · SIP · SMTP · SNMP · SSH · TELNET · RPC · RTP · RTCP · RTSP · TLS/SSL · SDP · SOAP · BGP · GTP · STUN · NTP · RIP· ...
TCP · UDP · DCCP · SCTP · RSVP · IGMP · ICMP ·ICMPv6 · OSPF· ...
IP (IPv4 · IPv6) · IS-IS · IPsec · ARP · RARP · ...
802.11 · Wi-Fi · WiMAX · ATM · DTM · Token Ring · Ethernet · FDDI · Frame Relay · GPRS · EVDO · HSPA · HDLC · PPP · PPTP · L2TP · ...
Ethernet physical layer · ISDN · Modems · PLC · SONET/SDH · G.709 · OFDM ·Optical Fiber · Coaxial Cable · Twisted Pair · ...
Ethernet is a large, diverse family of frame-based computer networking technologies that operate at many speeds for local area networks (LANs). The name comes from the physical concept of the ether. It defines a number of wiring and signaling standards for the physical layer, through means of network access at the Media Access Control (MAC)/Data Link Layer, and a common addressing format.
Ethernet has been standardized as IEEE 802.3. The combination of the twisted pair versions of Ethernet for connecting end systems to the network, along with the fiber optic versions for site backbones, has become the most widespread wired LAN technology. It has been in use from the 1990s to the present, largely replacing competing LAN standards such as coaxial cable Ethernet, token ring, FDDI, and ARCNET. In recent years, Wi-Fi, the wireless LAN standardized by IEEE 802.11, has been used instead of Ethernet for many home and small office networks and in addition to Ethernet in larger installations.

History
Ethernet was originally based on the idea of computers communicating over a shared coaxial cable acting as a broadcast transmission medium. The methods used show some similarities to radio systems, although there are major differences, such as the fact that it is much easier to detect collisions in a cable broadcast system than a radio broadcast. The common cable providing the communication channel was likened to the ether and it was from this reference that the name "Ethernet" was derived.
From this early and comparatively simple concept, Ethernet evolved into the complex networking technology that today powers the vast majority of local computer networks. The coaxial cable was later replaced with point-to-point links connected together by hubs and/or switches in order to reduce installation costs, increase reliability, and enable point-to-point management and troubleshooting. StarLAN was the first step in the evolution of Ethernet from a coaxial cable bus to a hub-managed, twisted-pair network. The advent of twisted-pair wiring enabled Ethernet to become a commercial success.
Above the physical layer, Ethernet stations communicate by sending each other data packets, small blocks of data that are individually sent and delivered. As with other IEEE 802 LANs, each Ethernet station is given a single 48-bit MAC address, which is used both to specify the destination and the source of each data packet. Network interface cards (NICs) or chips normally do not accept packets addressed to other Ethernet stations. Adapters generally come programmed with a globally unique address, but this can be overridden, either to avoid an address change when an adapter is replaced, or to use locally administered addresses.
Despite the very significant changes in Ethernet from a thick coaxial cable bus running at 10 Mbit/s to point-to-point links running at 1 Gbit/s and beyond, all generations of Ethernet (excluding very early experimental versions) share the same frame formats (and hence the same interface for higher layers), and can be readily (and in most cases, cheaply) interconnected.
Due to the ubiquity of Ethernet, the ever-decreasing cost of the hardware needed to support it, and the reduced panel space needed by twisted pair Ethernet, most manufacturers now build the functionality of an Ethernet card directly into PC motherboards, obviating the need for installation of a separate network card.

General description

Dealing with multiple users
Ethernet originally used a shared coaxial cable (the shared medium) winding around a building or campus to every attached machine. A scheme known as carrier sense multiple access with collision detection (CSMA/CD) governed the way the computers shared the channel. This scheme was simpler than the competing token ring or token bus technologies. When a computer wanted to send some information, it used the following algorithm:

CSMA/CD shared medium Ethernet

Frame ready for transmission
Is medium idle? If not, wait until it becomes ready and wait the interframe gap period (9.6 µs in 10 Mbit/s Ethernet).
Start transmitting
Does a collision occur? If so, go to collision detected procedure.
Reset retransmission counters and end frame transmission Main procedure
This can be likened to what happens at a dinner party, where all the guests talk to each other through a common medium (the air). Before speaking, each guest politely waits for the current speaker to finish. If two guests start speaking at the same time, both stop and wait for short, random periods of time (in Ethernet, this time is generally measured in microseconds). The hope is that by each choosing a random period of time, both guests will not choose the same time to try to speak again, thus avoiding another collision. Exponentially increasing back-off times (determined using the truncated binary exponential backoff algorithm) are used when there is more than one failed attempt to transmit.
Computers were connected to an Attachment Unit Interface (AUI) transceiver, which was in turn connected to the cable (later with thin Ethernet the transceiver was integrated into the network adaptor). While a simple passive wire was highly reliable for small Ethernets, it was not reliable for large extended networks, where damage to the wire in a single place, or a single bad connector, could make the whole Ethernet segment unusable. Multipoint systems are also prone to very strange failure modes when an electrical discontinuity reflects the signal in such a manner that some nodes would work properly while others work slowly because of excessive retries or not at all (see standing wave for an explanation of why); these could be much more painful to diagnose than a complete failure of the segment. Debugging such failures often involved several people crawling around wiggling connectors while others watched the displays of computers running a ping command and shouted out reports as performance changed.
Since all communications happen on the same wire, any information sent by one computer is received by all, even if that information is intended for just one destination. The network interface card interrupts the CPU only when applicable packets are received: the card ignores information not addressed to it unless it is put into "promiscuous mode". This "one speaks, all listen" property is a security weakness of shared-medium Ethernet, since a node on an Ethernet network can eavesdrop on all traffic on the wire if it so chooses. Use of a single cable also means that the bandwidth is shared, so that network traffic can slow to a crawl when, for example, the network and nodes restart after a power failure.

Continue transmission until minimum packet time is reached (jam signal) to ensure that all receivers detect the collision
Increment retransmission counter
Is maximum number of transmission attempts reached? If so, abort transmission.
Calculate and wait random backoff period based on number of collisions
Re-enter main procedure at stage 1 Collision detected procedure
For signal degradation and timing reasons, coaxial Ethernet segments had a restricted size which depended on the medium used. For example, 10BASE5 coax cables had a maximum length of 500 metres (1,640 feet). Also, as was the case with most other high-speed buses, Ethernet segments had to be terminated with a resistor at each end. For coaxial-cable-based Ethernet, each end of the cable had a 50-ohm resistor attached. Typically this resistor was built into a male BNC or N connector and attached to the last device on the bus, or, if vampire taps were in use, to the end of the cable just past the last device. If termination was not done, or if there was a break in the cable, the AC signal on the bus was reflected, rather than dissipated, when it reached the end. This reflected signal was indistinguishable from a collision, and so no communication could take place.
A greater length could be obtained by an Ethernet repeater, which took the signal from one Ethernet cable and repeated it onto another cable. If a collision was detected, the repeater transmitted a jam signal onto all ports to ensure collision detection. Repeaters could be used to connect segments such that there were up to five Ethernet segments between any two hosts, three of which could have attached devices. Repeaters could detect an improperly terminated link from the continuous collisions and stop forwarding data from it. Hence they alleviated the problem of cable breakages: when an Ethernet coax segment broke, while all devices on that segment were unable to communicate, repeaters allowed the other segments to continue working, although depending on which segment was broken and the layout of the network the partitioning that resulted may have made other segments unable to reach important servers and thus effectively useless.
People recognized the advantages of cabling in a star topology, primarily that only faults at the star point will result in a badly partitioned network, and network vendors started creating repeaters having multiple ports, thus reducing the number of repeaters required at the star point. Multiport Ethernet repeaters became known as "hubs". Network vendors such as DEC and SynOptics sold hubs that connected many 10BASE2 thin coaxial segments. There were also "multi-port transceivers" or "fan-outs". These could be connected to each other and/or a coax backbone. The best-known early example was DEC's DELNI. These devices allowed multiple hosts with AUI connections to share a single transceiver. They also allowed creation of a small standalone Ethernet segment without using a coaxial cable.
Ethernet on unshielded twisted-pair cables (UTP), beginning with StarLAN and continuing with 10BASE-T, was designed for point-to-point links only and all termination was built into the device. This changed hubs from a specialist device used at the center of large networks to a device that every twisted pair-based network with more than two machines had to use. The tree structure that resulted from this made Ethernet networks more reliable by preventing faults with (but not deliberate misbehavior of) one peer or its associated cable from affecting other devices on the network, although a failure of a hub or an inter-hub link could still affect lots of users. Also, since twisted pair Ethernet is point-to-point and terminated inside the hardware, the total empty panel space required around a port is much reduced, making it easier to design hubs with lots of ports and to integrate Ethernet onto computer motherboards.
Despite the physical star topology, hubbed Ethernet networks still use half-duplex and CSMA/CD, with only minimal activity by the hub, primarily the Collision Enforcement signal, in dealing with packet collisions. Every packet is sent to every port on the hub, so bandwidth and security problems aren't addressed. The total throughput of the hub is limited to that of a single link and all links must operate at the same speed.
Collisions reduce throughput by their very nature. In the worst case, when there are lots of hosts with long cables that attempt to transmit many short frames, excessive collisions can reduce throughput dramatically. However, a Xerox report in 1980 summarized the results of having 20 fast nodes attempting to transmit packets of various sizes as quickly as possible on the same Ethernet segment.

Ethernet repeaters and hubs
While repeaters could isolate some aspects of Ethernet segments, such as cable breakages, they still forwarded all traffic to all Ethernet devices. This created practical limits on how many machines could communicate on an Ethernet network. Also as the entire network was one collision domain and all hosts had to be able to detect collisions anywhere on the network the number of repeaters between the furthest nodes was limited. Finally segments joined by repeaters had to all operate at the same speed, making phased in upgrades impossible
To alleviate these problems, bridging was created to communicate at the data link layer while isolating the physical layer. With bridging, only well-formed packets are forwarded from one Ethernet segment to another; collisions and packet errors are isolated. Bridges learn where devices are, by watching MAC addresses, and do not forward packets across segments when they know the destination address is not located in that direction.
Prior to discovery of network devices on the different segments, Ethernet bridges and switches work somewhat like Ethernet hubs, passing all traffic between segments. However, as the switch discovers the addresses associated with each port, it only forwards network traffic to the necessary segments improving overall performance. Broadcast traffic is still forwarded to all network segments. Bridges also overcame the limits on total segments between two hosts and allowed the mixing of speeds, both of which became very important with the introduction of Fast Ethernet.
Early bridges examined each packet one by one using software on a CPU, and some of them were significantly slower than hubs (multi-port repeaters) at forwarding traffic, especially when handling many ports at the same time. In 1989 the networking company Kalpana introduced their EtherSwitch, the first Ethernet switch. An Ethernet switch does bridging in hardware, allowing it to forward packets at full wire speed. It is important to remember that the term switch was invented by device manufacturers and does not appear in the 802.3 standard. Functionally, the two terms are interchangeable.
Since packets are typically only delivered to the port they are intended for, traffic on a switched Ethernet is slightly less public than on shared-medium Ethernet. Despite this, switched Ethernet should still be regarded as an insecure network technology, because it is easy to subvert switched Ethernet systems by means such as ARP spoofing and MAC flooding. The bandwidth advantages, the slightly better isolation of devices from each other, the ability to easily mix different speeds of device and the elimination of the chaining limits inherent in non-switched Ethernet have made switched Ethernet the dominant network technology.
When a twisted pair or fiber link segment is used and neither end is connected to a hub, full-duplex Ethernet becomes possible over that segment. In full duplex mode both devices can transmit and receive to/from each other at the same time, and there is no collision domain. This doubles the aggregate bandwidth of the link and is sometimes advertised as double the link speed (e.g. 200 Mbit/s) to account for this. However, this is misleading as performance will only double if traffic patterns are symmetrical (which in reality they rarely are). The elimination of the collision domain also means that all the link's bandwidth can be used and that segment length is not limited by the need for correct collision detection (this is most significant with some of the fiber variants of Ethernet).

Dual speed hubs
Simple switched Ethernet networks, while an improvement over hub based Ethernet, suffer from a number of issues:
Some switches offer a variety of tools to combat these issues including:

They suffer from single points of failure. If any link fails some devices will be unable to communicate with other devices and if the link that fails is in a central location lots of users can be cut off from the resources they require.
It is possible to trick switches or hosts into sending data to your machine even if it's not intended for it, as indicated above.
Large amounts of broadcast traffic whether malicious, accidental or simply a side effect of network size can flood slower links and/or systems.

• It is possible for any host to flood the network with broadcast traffic forming a denial of service attack against any hosts that run at the same or lower speed as the attacking device.
  As the network grows normal broadcast traffic takes up an ever greater amount of bandwidth.
  If switches are not multicast aware multicast traffic will end up treated like broadcast traffic due to being directed at a MAC with no associated port.
  If switches discover more MAC addresses than they can store (either through network size or through an attack) some addresses must inevitably be dropped and traffic to those addresses will be treated the same way as traffic to unknown addresses, that is essentially the same as broadcast traffic (this issue is known as failopen).
  They suffer from bandwidth choke points where a lot of traffic is forced down a single link.
  Spanning-tree protocol to maintain the active links of the network as a tree while allowing physical loops for redundancy.
  Various port protection features, as it is far more likely an attacker will be on an end system port than on a switch-switch link.
  VLANs to keep different classes of users separate while using the same physical infrastructure.
  fast routing at higher levels to route between those VLANs.
  Link aggregation to add bandwidth to overloaded links and to provide some measure of redundancy, although the links won't protect against switch failure because they connect the same pair of switches. More advanced networks
  
  
  Main articles: Autonegotiation and Duplex mismatch Autonegotiation and duplex mismatch
  
  

  Main article: Ethernet II framing Ethernet frame types and the EtherType field
  
  

  Main article: Ethernet physical layer Physical layer
  
  Networking standards that are not part of the IEEE 802.3 Ethernet standard, but support the Ethernet frame format, and are capable of interoperating with it.
  

  
  
  • LattisNet — A SynOptics pre-standard twisted-pair 10 Mbit/s variant.
    100BaseVG — An early contender for 100 Mbit/s Ethernet. It runs over Category 3 cabling. Uses four pairs. Commercial failure.
    TIA 100BASE-SX — Promoted by the Telecommunications Industry Association. 100BASE-SX is an alternative implementation of 100 Mbit/s Ethernet over fiber; it is incompatible with the official 100BASE-FX standard. Its main feature is interoperability with 10BASE-FL, supporting autonegotiation between 10 Mbit/s and 100 Mbit/s operation – a feature lacking in the official standards due to the use of differing LED wavelengths. It is targeted at the installed base of 10 Mbit/s fiber network installations.
    TIA 1000BASE-TX — Promoted by the Telecommunications Industry Association, it was a commercial failure, and no products exist. 1000BASE-TX uses a simpler protocol than the official 1000BASE-T standard so the electronics can be cheaper, but requires Category 6 cabling.
    Networking standards that do not use the Ethernet frame format but can still be connected to Ethernet using MAC-based bridging.
    
    
    
    • 802.11 — A standard for wireless networking often paired with an Ethernet backbone.
      10BaseS — Ethernet over VDSL
      Long Reach Ethernet
      Avionics Full-Duplex Switched Ethernet
      Metro Ethernet Implementations
      
      10 gigabit Ethernet
      100 gigabit Ethernet
      8P8C modular connector and extension cable
      Attachment Unit Interface
      Category 5 cable
      List of device bandwidths
      Chaosnet
      Ethernet Automatic Protection System
      Ethernet crossover cable
      Ethernet flow control
      Fast Ethernet
      Gigabit Ethernet
      Ethernet over twisted pair
      Ethernet physical layer
      IEEE 802.3
      Jumbogram
      MII and PHY
      Power line communication
      Power over Ethernet
      Spanning Tree Protocol
      Virtual LAN
      Wake-on-LAN