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UDP-based Data Transfer Protocol (UDT), is a high-performance data transfer protocol designed for transferring large volumetric datasets over high-speed wide area networks. Such settings are typically disadvantageous for the more common TCP protocol. Initial versions were developed and tested on very high-speed networks (1 Gbit/s, 10 Gbit/s, etc.); however, recent versions of the protocol have been updated to support the commodity Internet as well. For example, the protocol now supports rendezvous connection setup, which is a desirable feature for traversing NAT firewalls using UDP. UDT has an open source implementation which can be found on SourceForge. It is one of the most popular solutions for supporting high-speed data transfer and is part of many research projects and commercial products. ==Background== UDT was developed by Yunhong Gu〔http://scholar.google.co.in/citations?user=Iss3wgUAAAAJ&hl=en〕 during his PhD studies at the National Center for Data Mining (NCDM) of University of Illinois at Chicago in the laboratory of Dr. Robert Grossman. Dr. Gu continues to maintain and improve the protocol after graduation. The UDT project started in 2001, when inexpensive optical networks became popular and triggered a wider awareness of TCP efficiency problems over wide area high speed networks. The first version of UDT, also known as SABUL (Simple Available Bandwidth Utility Library), was designed to support bulk data transfer for scientific data movement over private networks. SABUL used UDP for data transfer and a separate TCP connection for control messages. In October, 2003, the NCDM achieved a 6.8 gigabits per second transfer from Chicago, USA to Amsterdam, Netherlands. During the 30-minute test they transmitted approximately 1.4 terabytes of data. SABUL was later renamed to UDT starting with version 2.0, which was released in 2004. UDT2 removed the TCP control connection in SABUL and used UDP for both data and control information. UDT2 also introduced a new congestion control algorithm that allowed the protocol to run "fairly and friendly" with concurrent UDT and TCP flows. UDT3 (2006) extended the usage of the protocol to the commodity Internet. Congestion control was tuned to support relatively low bandwidth as well. UDT3 also significantly reduced the use of system resources (CPU and memory). Additionally, UDT3 allows users to easily define and install their own congestion control algorithms. UDT4 (2007) introduced several new features to better support high concurrency and firewall traversing. UDT4 allowed multiple UDT connections to bind to the same UDP port and it also supported rendezvous connection setup for easier UDP hole punching. A fifth version of the protocol is currently in the planning stage. Possible features include the ability to support multiple independent sessions over a single connection. Moreover, since the absence of a security feature for UDT has been an issue with its initial implementation in a commercial environment, Bernardo (2011) has developed a security architecture for UDT as part of his PhD studies. This architecture however is undergoing enhancement to support UDT in various network environments (i.e., optical networks). 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「UDP-based Data Transfer Protocol」の詳細全文を読む スポンサード リンク
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