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The small form-factor pluggable (SFP) is a compact, hot-pluggable transceiver used for both telecommunication and data communications applications. The form factor and electrical interface are specified by a multi-source agreement (MSA). It interfaces a network device motherboard (for a switch, router, media converter or similar device) to a fiber optic or copper networking cable. It is a popular industry format jointly developed and supported by many network component vendors. SFP transceivers are designed to support SONET, gigabit Ethernet, Fibre Channel, and other communications standards. Due to its smaller size, SFP obsolesces the formerly ubiquitous gigabit interface converter (GBIC); the SFP is sometimes referred to as a Mini-GBIC although no device with this name has ever been defined in the MSAs. ==Types== SFP transceivers are available with a variety of transmitter and receiver types, allowing users to select the appropriate transceiver for each link to provide the required ''optical reach'' over the available optical fiber type (e.g. multi-mode fiber or single-mode fiber). Optical SFP modules are commonly available in several different categories: * for multi-mode fiber, with black or beige〔 extraction lever * * SX - 850 nm, for a maximum of 550 m at 1.25 Gbit/s (gigabit Ethernet) or 150m at 4.25 Gbit/s (Fibre Channel) * for single-mode fiber, with blue〔 extraction lever * * LX - 1310 nm, for distances up to 10 km * * EX - 1310 nm, for distances up to 40 km * * ZX - 1550 nm, for distances up to 80 km, with green extraction lever (see GLC-ZX-SM1) 〔 * * EZX - 1550 nm, for distances up to 160 km 〔 * * BX - 1490 nm/1310 nm, Single Fiber Bi-Directional Gigabit SFP Transceivers, paired as BS-U and BS-D for Uplink and Downlink respectively, also for distances up to 10 km. Variations of bidirectional SFPs are also manufactured which use 1550 nm in one direction. * * 1550 nm 40 km (XD), 80 km (ZX), 120 km (EX or EZX) * * SFSW – Single Fiber Single Wavelength transceivers, for bi-directional traffic on a single fiber. Coupled with CWDM, these double the traffic density of fiber links.〔(【引用サイトリンク】title=Single-fiber single-wavelength gigabit transceivers )〕〔(【引用サイトリンク】title=The principle of Single Wavelength BiDi Transceiver )〕 * * CWDM and DWDM transceivers at various wavelengths achieving various maximum distances * for copper twisted pair cabling * * 1000BASE-T - these modules incorporate significant interface circuitry and can only be used for gigabit Ethernet, as that is the interface they implement. They are not compatible with (or rather: do not have equivalents for) Fiber channel or SONET. ===SFP+=== The enhanced small form-factor pluggable (SFP+) is an enhanced version of the SFP that supports data rates up to 16 Gbit/s. The SFP+ specification was first published on May 9, 2006, and version 4.1 published on July 6, 2009.〔(【引用サイトリンク】date= July 6, 2009 )〕 SFP+ supports 8 Gbit/s Fibre Channel, 10 Gigabit Ethernet and Optical Transport Network standard OTU2. It is a popular industry format supported by many network component vendors. Although the SFP+ standard does not include mention of 16G Fibre Channel it can be used at this speed.〔(【引用サイトリンク】title=Characterizing an SFP+ Transceiver at the 16G Fibre Channel Rate )〕 Besides the data rate, the big difference between 8G Fibre Channel and 16G Fibre Channel is the encoding method. 64b/66b encoding used for 16G is a more efficient encoding mechanism than 8b/10b used for 8G, and allows for the data rate to double without doubling the line rate. The result is the 14.025 Gbit/s line rate for 16G Fibre Channel. In comparison to earlier XENPAK or XFP modules, SFP+ modules leave more circuitry to be implemented on the host board instead of inside the module.〔(【引用サイトリンク】title=10-Gigabit Ethernet camp eyes SFP+ )〕 Consideration has to be given to whether the module is linear or limiting. Linear SFP+ modules are most appropriate for 10GBASE-LRM; otherwise, limiting modules are preferred. SFP+ also introduces Direct Attach for connecting two SFP+ ports without dedicated transceivers. 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「Small form-factor pluggable transceiver」の詳細全文を読む スポンサード リンク
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