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In computer networking, Gigabit Ethernet (GbE or 1 GigE) is a term describing various technologies for transmitting Ethernet frames at a rate of a gigabit per second (1,000,000,000 bits per second), as defined by the IEEE 802.3-2008 standard. It came into use beginning in 1999, gradually supplanting Fast Ethernet in wired local networks, where it performed considerably faster. The cables and equipment are very similar to previous standards and have been very common and economical since 2010. Half-duplex gigabit links connected through repeater hubs were part of the IEEE specification,〔A single repeater per collision domain is defined in IEEE 802.3 2008 Section 3: 41. Repeater for 1000 Mb/s baseband networks〕 but the specification is not updated anymore and full-duplex operation with switches is used exclusively. ==History== Ethernet was the result of the research done at Xerox PARC in the early 1970s. Ethernet later evolved into a widely implemented physical and link layer protocol. Fast Ethernet increased speed from 10 to 100 megabits per second (Mbit/s). Gigabit Ethernet was the next iteration, increasing the speed to 1000 Mbit/s. The initial standard for Gigabit Ethernet was produced by the IEEE in June 1998 as IEEE 802.3z, and required optical fiber. 802.3z is commonly referred to as 1000BASE-X, where -X refers to either -CX, -SX, -LX, or (non-standard) -ZX. For the history behind the "X" see Fast Ethernet. IEEE 802.3ab, ratified in 1999, defines Gigabit Ethernet transmission over unshielded twisted pair (UTP) category 5, 5e, or 6 cabling and became known as 1000BASE-T. With the ratification of 802.3ab, Gigabit Ethernet became a desktop technology as organizations could use their existing copper cabling infrastructure. IEEE 802.3ah, ratified in 2004 added two more gigabit fiber standards, 1000BASE-LX10 (which was already widely implemented as vendor specific extension) and 1000BASE-BX10. This was part of a larger group of protocols known as Ethernet in the First Mile. Initially, Gigabit Ethernet was deployed in high-capacity backbone network links (for instance, on a high-capacity campus network). In 2000, Apple's Power Mac G4 and PowerBook G4 were the first mass-produced personal computers featuring the 1000BASE-T connection. It quickly became a built-in feature in many other computers. 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「Gigabit Ethernet」の詳細全文を読む スポンサード リンク
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