X.25 is an ITU-T standard protocol suite for packet-switched data communication in wide area networks. It was defined by the International Telegraph and Telephone Consultative Committee in a series of drafts and finalized in a publication known as The Orange Book in 1976; this makes it one of the oldest packet-switching communication protocols available. The protocol suite is designed as three conceptual layers, which correspond to the lower three layers of the seven-layer OSI model, it supports functionality not found in the OSI network layer. Networks using X.25 were popular during the late 1970s and 1980s with telecommunications companies and in financial transaction systems such as automated teller machines. An X.25 WAN consists of packet-switching exchange nodes as the networking hardware, leased lines, plain old telephone service connections, or ISDN connections as physical links. However, most users have moved to Internet Protocol systems instead. X. 25 was is still used by aviation, purchasable from telecoms companies.
X.25 was available in niche applications such as Retronet that allow vintage computers to use the Internet. Based on significant contributions by Rémi Després and British researchers, X.25 was developed in the ITU-T Study Group VII based upon a number of emerging data network projects. Various updates and additions were worked into the standard recorded in the ITU series of technical books describing the telecommunication systems; these books were published every fourth year with different-colored covers. The X.25 specification is only part of the larger set of X-Series. Public data network was the common name given to the international collection of X.25 providers, many set up by PTT providers. Their combined network had large global coverage into the 1990s. Publicly accessible X.25 networks were set up in most countries during the 1970s and 1980s, to lower the cost of accessing various online services. Examples include Iberpac, TRANSPAC, Tymnet, Euronet, PSS, Datanet 1 and AUSTPAC. Beginning in the early 1990s, in North America, use of X.25 networks started to be replaced by Frame Relay services offered by national telephone companies.
Most systems that required X.25 now use TCP/IP, however it is possible to transport X.25 over TCP/IP when necessary. X.25 networks are still in use throughout the world. A variant called AX.25 is used by amateur packet radio. Racal Paknet, now known as Widanet, is still in operation in many regions of the world, running on an X.25 protocol base. In some countries, like the Netherlands or Germany, it is possible to use a stripped version of X.25 via the D-channel of an ISDN-2 connection for low-volume applications such as point-of-sale terminals. Additionally X.25 is still under heavy use in the aeronautical business though a transition to modern protocols like X.400 is without option as X.25 hardware becomes rare and costly. As as March 2006, the United States National Airspace Data Interchange Network has used X.25 to interconnect remote airfields with Air Route Traffic Control Centers. France was one of the last remaining countries where commercial end-user service based on X.25 operated. Known as Minitel it was based on Videotex, itself running on X.25.
In 2002, Minitel had about 9 million users, in 2011, it still accounted for about 2 million users in France when France Télécom announced it would shut down the service by 30 June 2012. As planned, service was terminated 30 June 2012. There were 800,000 terminals still in operation at the time; the general concept of the X. 25 was to create a global packet-switched network. Much of the X.25 system is a description of the rigorous error correction needed to achieve this, as well as more efficient sharing of capital-intensive physical resources. The X. 25 specification defines only the interface between an X. 25 network. X.75, a protocol similar to X.25, defines the interface between two X.25 networks to allow connections to traverse two or more networks. X.25 does not specify how the network operates internally – many X.25 network implementations used something similar to X.25 or X.75 internally, but others used quite different protocols internally. The ISO protocol equivalent to X.25, ISO 8208, is compatible with X.25, but additionally includes provision for two X.25 DTEs to be directly connected to each other with no network in between.
By separating the Packet-Layer Protocol, ISO 8208 permits operation over additional networks such as ISO 8802 LLC2 and the OSI data link layer. X.25 defined three basic protocol levels or architectural layers. In the original specifications these were referred to as levels and had a level number, whereas all ITU-T X.25 recommendations and ISO 8208 standards released after 1984 refer to them as layers. The layer numbers were dropped to avoid confusion with the OSI Model layers. Physical layer: This layer specifies the physical, electrical and procedural characteristics to control the physical link between a DTE and a DCE. Common implementations use X. 21, EIA-449 or other serial protocols. Data link layer: The data link layer consists of the link access procedure for data interchange on the link between a DTE and a DCE. In its implementation, the Link Access Procedure, Balanced is a data link protocol that manages a communication session and controls t
The Salt March known as the Salt Satyagraha, Dandi March and the Dandi Satyagraha, was an act of nonviolent civil disobedience in colonial India led by Mohandas Karamchand Gandhi. The 24-day march lasted from 12 March 1930 to 6 April 1930 as a direct action campaign of tax resistance and nonviolent protest against the British salt monopoly. Mahatma Gandhi started this march with 80 of his trusted volunteers. Walking ten miles a day for 24 days, the march spanned over 240 miles, from Sabarmati Ashram, 240 miles to Dandi, called Navsari at that time. Growing numbers of Indians joined them along the way; when Gandhi broke the salt laws at 6:30 am on 6 April 1930, it sparked large scale acts of civil disobedience against the British Raj salt laws by millions of Indians. After making the salt by evaporation at Dandi, Gandhi continued southward along the coast, making salt and addressing meetings on the way; the Congress Party planned to stage a satyagraha at the Dharasana Salt Works, 25 miles south of Dandi.
However, Gandhi was arrested on the midnight of 4–5 May 1930, just days before the planned action at Dharasana. The Dandi March and the ensuing Dharasana Satyagraha drew worldwide attention to the Indian independence movement through extensive newspaper and newsreel coverage; the satyagraha against the salt tax continued for a year, ending with Gandhi's release from jail and negotiations with Viceroy Lord Irwin at the Second Round Table Conference. Over 60,000 Indians were jailed as a result of the Salt Satyagraha. However, it failed to result in major concessions from the British; the Salt Satyagraha campaign was based upon Gandhi's principles of non-violent protest called satyagraha, which he loosely translated as "truth-force". It is formed from the Sanskrit words satya, "truth", agraha, "insistence". In early 1930 the Indian National Congress chose satyagraha as their main tactic for winning Indian sovereignty and self-rule from British rule and appointed Gandhi to organise the campaign. Gandhi chose the 1882 British Salt Act as the first target of satyagraha.
The Salt March to Dandi, the beating by British police of hundreds of nonviolent protesters in Dharasana, which received worldwide news coverage, demonstrated the effective use of civil disobedience as a technique for fighting social and political injustice. The satyagraha teachings of Gandhi and the March to Dandi had a significant influence on American activists Martin Luther King Jr. James Bevel, others during the Civil Rights Movement for civil rights for African Americans and other minority groups in the 1960s; the march was the most significant organised challenge to British authority since the Non-cooperation movement of 1920–22, directly followed the Purna Swaraj declaration of sovereignty and self-rule by the Indian National Congress on 26 January 1930. It gained worldwide attention which gave impetus to the Indian independence movement and started the nationwide Civil Disobedience Movement. At midnight on 31 December 1929, the Indian National Congress raised the tricolour flag of India on the banks of the Ravi at Lahore.
The Indian National Congress, led by Gandhi and Jawaharlal Nehru, publicly issued the Declaration of sovereignty and self-rule, or Purna Swaraj, on 26 January 1930. The declaration included the readiness to withhold taxes, the statement: We believe that it is the inalienable right of the Indian people, as of any other people, to have freedom and to enjoy the fruits of their toil and have the necessities of life, so that they may have full opportunities of growth. We believe that if any government deprives a people of these rights and oppresses them the people have a further right to alter it or abolish it; the British government in India has not only deprived the Indian people of their freedom but has based itself on the exploitation of the masses, has ruined India economically, politically and spiritually. We believe therefore, that India must sever the British connection and attain Purna Swaraji or complete sovereignty and self-rule; the Congress Working Committee gave Gandhi the responsibility for organising the first act of civil disobedience, with Congress itself ready to take charge after Gandhi's expected arrest.
Gandhi's plan was to begin civil disobedience with a satyagraha aimed at the British salt tax. The 1882 Salt Act gave the British a monopoly on the collection and manufacture of salt, limiting its handling to government salt depots and levying a salt tax. Violation of the Salt Act was a criminal offence. Though salt was available to those living on the coast, Indians were forced to buy it from the colonial government. Gandhi's choice of the salt tax was met with incredulity by the Working Committee of the Congress, Jawaharlal Nehru and Dibyalochan Sahoo were ambivalent; the Statesman, a prominent newspaper, wrote about the choice: "It is difficult not to laugh, we imagine that will be the mood of most thinking Indians."The British establishment too was not disturbed by these plans of resistance against the salt tax. The Viceroy himself, Lord Irwin, did not take the threat of a salt protest writing to London, "At present the prospect of a salt campaign does not keep me awake at night."However, Gandhi had sound reasons for his decision.
An item of daily use could resonate more with all classes of citizens than an abstract demand for greater political rights. The salt tax represented 8.2% of the British Raj tax revenue, hurt the poorest Indians the most significantly. Explaining his choice, Gandhi said, "Next to air and water, salt is the gr
The U. S. Route 395 North Spokane Corridor is a 10.5-mile-long freeway - with 5.42 miles complete and operational – running north–south along the eastern border of Spokane and parts of unincorporated Spokane County to the north. The $2.2 billion project is designed to improve freight and commuter mobility through the Spokane Metropolitan Area. As of 2016, only the northern half from Francis Avenue to U. S. Route 395 is open to traffic; the project is being managed by the Washington State Department of Transportation and will create a freeway with a speed limit of 60 mph along a new alignment linking Interstate 90, to the existing US Route 395 10.5 miles to the north in the Wandermere area. When completed, the multi-modal facility is expected to have general travel lanes, with right-of-way reserved for a future high-capacity transit system with park-and-ride lots. Additionally, a pedestrian and bicycle trail will run along the entire highway alignment; the project is ranked 19 of 43 on the Congressional High Priority Corridor list of the National Highway System.
When completed, the corridor is expected to carry over 150,000 vehicles per day. The North Spokane Corridor is part of Washington's state highway system and, upon completion, will adopt the US 395 designation; the WSDOT considers the corridor a spur of US 395 and refers to the roadway as "Future US 395" on its official state highway maps and roadway guide signs. The ultimate route of the highway runs from I-90, just east of Downtown Spokane, northward about 10.5 miles meeting the existing US 395 at Wandermere, just north of Spokane. The northern end of the corridor was constructed as a seamless connection to the existing US 395, rerouting the existing highway onto the North Spokane Corridor; the construction of this interchange replaced the existing alignment of US 395 that flowed directly onto Division Street, with an exit to Division off of the freeway. Because the corridor's northern end ties in with a portion of US 395, redeveloped into a limited-access highway in the late 1990s, the completion of the corridor will create a controlled-access highway from the vicinity of Hatch Road to I-90.
The North Spokane Corridor is planned to bypass the busy Division Street corridor. The new freeway will carry the US 395 designation, run about one mile east of where it was planned in the 1960s and 1970s. While the new freeway would be a good routing for US 2 to bypass Spokane, that highway is scheduled to stay on its current routing in order to keep most of Division Street in the state highway system, it will be easy for motorists on US 2 to avoid this by using the freeway instead of Division Street. On the north side, a full interchange has been constructed at US 2 in the Mead area near Farwell Road; this route uses the entire North Spokane Corridor except the northernmost one mile section between US 2 and Wandermere. Division street between the "Y" and Wandermere will no longer be in the state highway system; this includes about one-half mile of the new section of Division Street just north of Farwell Road. Plans for a North Spokane Freeway date back to 1946. Earlier projects were cancelled due to local opposition.
The current project began construction in 2001. The idea of having a freeway run northward through Spokane was conceived in 1946 after the Spokane traffic survey that year; the city of Spokane needed some sort of a major north–south traffic facility to relieve congestion. After several reports and studies, the first plans for the freeway were released in 1956 with an estimated cost of just $13 million, those plans were shelved in 1958 as the construction of the Interstate Highway System was prioritized over the construction of the north–south freeway; as a result, cheaper alternatives, such as one-way paired couplets, were discussed. In 1964, the Spokane Metropolitan Area Transportation Study was formed to fulfill requirements of Federal Highway Act of 1962, in 1970, along with the Department of Highways, released the "Corridor Study for North Spokane and North Suburban Area Freeway", it recommended a north -- south freeway along Nevada streets. Though a full freeway interchange was built connecting Hamilton Street with I-90, residents blocked any further construction through this area.
After 33 years of further discussions and proposals, the final environmental impact statement for the current version of the project was approved in April 1997. The first phase of the NSC, consisting of grading between Hawthorne Road and US 2, broke ground in August 2001; the first ribbon cutting ceremony occurred on the eighth anniversary of the ground breaking, August 22, 2009. To reduce costs, the scope of construction was reduced in 2008, reducing the northmost portion from six lanes to four, eliminating part of the interchange at Wellesley Avenue, constructing the freeway at ground level, rather than below; this reduced the cost of that portion from $720 million to $285 million, while still allowing for those improvements later. On June 13, 2012, the NSC opened a new section from the newly constructed interchange at US 2 to the new Wandermere/US 3