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Janet is a private, UK government-funded organisation, which provides computer network and related collaborative services to UK research and education. All further- and higher-education organisations in the UK are connected to the Janet network, as are all the Research Councils; the majority of these sites are connected via 20 metropolitan area networks across the UK (though Janet refers to these as Regional Networks, emphasising that Janet connections are not just confined to a metropolitan area〔(Regional Delivery Options )〕). The network also carries traffic between schools within the UK, although many of the schools' networks maintain their own general Internet connectivity. The name was originally a contraction of Joint Academic NETwork but it is now known as Janet in its own right. The network is linked to other European and worldwide NRENs through GEANT and peers extensively with other ISPs at Internet Exchange Points in the UK.〔(Peering Networks Detailed View )〕 Any other networks are reached via transit services from commercial ISPs using Janet's Peering Policy.〔(Janet Peering Policy )〕 The Janet network is operated by Janet. Janet is also responsible for the .ac.uk and .gov.uk domains. It is funded by Jisc. On 1 December 2012, Janet and Jisc Collections joined together to form Jisc Collections and Janet Limited, as subsidiary organisations to Jisc. Janet continues to operate under the brand name of Janet, with the same remit of providing a world class network and related collaborative services to UK research and education. Janet was previously known as the JNT Association, and prior to that, UKERNA (the United Kingdom Education and Research Networking Association). ==History== Janet developed out of a number of local and research networks dating back to the 1970s. By 1980, a number of national computer facilities (ULCC London, UMRCC Manchester, Rutherford Appleton Laboratory serving the Science and Engineering Research Council community), each with their own star network had developed. There were also regional networks centred on Bristol, Edinburgh and Newcastle, where groups of institutions had pooled resources to provide better computing facilities than could be afforded individually. These networks were each based on one manufacturer's standards, were mutually incompatible, and overlapping. In the early 1980s a standardisation and interconnect effort started, hosted on an expansion of the SERCnet X.25 research network. The system first went live in April 1983, hosting about 50 sites with line speeds of 9.6 kbit/s. In the mid-80s the backbone was upgraded to a 2 Mbit/s backbone with 64 kbit/s access links, and a further upgrade in the early 1990s sped the backbone to 8 Mbit/s and the access links to 2 Mbit/s, making Janet the fastest X.25 network in the world. The Janet effort resulted in the standardisation known as the Coloured Book protocols, which provided the first complete X.25 standard. The naming scheme used on Janet (JANET NRS) had similarities to the Internet's Domain Name System, but with domains specified in big-endian format rather than the little-endian style used by DNS. There had been some talk of moving Janet to OSI protocols in the 1990s, but changes in the networking world meant this never happened. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「JANET」の詳細全文を読む スポンサード リンク
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