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Concept
DATAPAC
Résumé
DATAPAC, or Datapac in some documents, was Canada's packet switched X.25-equivalent data network. Initial work on a data-only network started in 1972 and was announced by Bell Canada in 1974 as Dataroute. DATAPAC was implemented by adding packet switching to the existing Dataroute networks. It opened for use in 1976 as the world's first public data network based on X.25.
Operated first by Trans-Canada Telephone System, then Telecom Canada, then the Stentor Alliance, it finally reverted to Bell Canada when the Stentor Alliance was dissolved in 1999. Like most X.25 networks in the western world, DATAPAC services were largely replaced by TCP/IP in the 1990s and 2000s. Bell phased out the service on 31 December 2009.
Bell Canada had long offered leased lines to large business customers like banks and insurance companies who needed to move data between their offices. The company offered only the physical link, it was up to the customers to provide the equipment needed to link their systems together, typically provided by their primary mainframe vendors. Such a set-up was not inexpensive to install or operate.
In the early 1970s, Bell began exploring ways to make this service more attractive to smaller companies and offices. This led to Dataroute, carried on the coast-to-coast Trans Canada Microwave network. In contrast to earlier leased lines, Dataroute allowed multiple customers to share a single channel, folded together using time division multiplexing, and then sent across the country on the existing high-speed microwave links. Customers could also save money if they only needed lower data speeds or to exchange data at certain times of the day. On its commercial release in February 1973, it was given the name The Dataroute.
Through this period, the first experimental packet switching networks were being installed. These offered the ability to greatly increase the number of customers able to use the network. In time division multiplexing, each customer is given a fixed time slot, which is used up even if they do not transmit anything during that period.
Source officielle
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