small form-factor pluggable transceiver

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Small form-factor pluggable transceiver Front view of SFP module (LC connector). The blue extraction lever indicates operation with single-mode fiber. The small form-factor pluggable (SFP) is a compact, hot-pluggable transceiver used for both telecommunication and data communications appli- cations. The form factor and electrical interface are specified by a multi-source agreement (MSA). It in- terfaces 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. [1] 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. 1 Types SFP transceivers are available with a variety of transmit- ter and receiver types, allowing users to select the appro- priate transceiver for each link to provide the required op- tical 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 [1] extrac- tion 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) [2] for single-mode fiber, with blue [1] extraction lever LX - 1310 nm, for distances up to 10 km EX - 1310 nm, for distances up to 40 km [3] ZX - 1550 nm, for distances up to 80 km, with green extraction lever (see GLC-ZX- SM1) [3][4] EZX - 1550 nm, for distances up to 160 km [3] BX - 1490 nm/1310 nm, Single Fiber Bi- Directional Gigabit SFP Transceivers, paired as BS-U and BS-D for Uplink and Down- link respectively, also for distances up to 10 km. [5][6] 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 sin- gle fiber. Coupled with CWDM, these double the traffic density of fiber links. [7][8] CWDM and DWDM transceivers at various wavelengths achieving various maximum dis- tances for copper twisted pair cabling 1000BASE-T - these modules incorporate sig- nificant interface circuitry [9] and can only be used for gigabit Ethernet, as that is the inter- face they implement. They are not compatible with (or rather: do not have equivalents for) Fiber channel or SONET. 2 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 pub- lished on May 9, 2006, and version 4.1 published on July 6, 2009. [10] SFP+ supports 8 Gbit/s Fibre Channel, 10 Gi- gabit 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. [11] Be- sides the data rate, the big difference between 8G Fibre 1

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Page 1: Small Form-factor Pluggable Transceiver

Small form-factor pluggable transceiver

Front view of SFP module (LC connector). The blue extractionlever indicates operation with single-mode fiber.

The small form-factor pluggable (SFP) is acompact, hot-pluggable transceiver used for bothtelecommunication and data communications appli-cations. The form factor and electrical interface arespecified by a multi-source agreement (MSA). It in-terfaces a network device motherboard (for a switch,router, media converter or similar device) to a fiber opticor copper networking cable. It is a popular industryformat jointly developed and supported by many networkcomponent vendors.[1] SFP transceivers are designed tosupport SONET, gigabit Ethernet, Fibre Channel, andother communications standards. Due to its smaller size,SFP obsolesces the formerly ubiquitous gigabit interfaceconverter (GBIC); the SFP is sometimes referred to as aMini-GBIC although no device with this name has everbeen defined in the MSAs.

1 Types

SFP transceivers are available with a variety of transmit-ter and receiver types, allowing users to select the appro-priate transceiver for each link to provide the required op-tical reach over the available optical fiber type (e.g. multi-mode fiber or single-mode fiber). Optical SFP modulesare commonly available in several different categories:

• for multi-mode fiber, with black or beige[1] extrac-tion lever

• SX - 850 nm, for a maximum of 550 m at1.25 Gbit/s (gigabit Ethernet) or 150m at 4.25Gbit/s (Fibre Channel)[2]

• for single-mode fiber, with blue[1] extraction lever

• LX - 1310 nm, for distances up to 10 km• EX - 1310 nm, for distances up to 40 km [3]

• ZX - 1550 nm, for distances up to 80 km,with green extraction lever (see GLC-ZX-SM1) [3][4]

• EZX - 1550 nm, for distances up to 160 km[3]

• BX - 1490 nm/1310 nm, Single Fiber Bi-Directional Gigabit SFP Transceivers, pairedas BS-U and BS-D for Uplink and Down-link respectively, also for distances up to 10km.[5][6] Variations of bidirectional SFPs arealso manufactured which use 1550 nm in onedirection.

• 1550 nm 40 km (XD), 80 km (ZX), 120 km(EX or EZX)

• SFSW – Single Fiber Single Wavelengthtransceivers, for bi-directional traffic on a sin-gle fiber. Coupled with CWDM, these doublethe traffic density of fiber links.[7][8]

• CWDM and DWDM transceivers at variouswavelengths achieving various maximum dis-tances

• for copper twisted pair cabling

• 1000BASE-T - thesemodules incorporate sig-nificant interface circuitry[9] and can only beused for gigabit Ethernet, as that is the inter-face they implement. They are not compatiblewith (or rather: do not have equivalents for)Fiber channel or SONET.

2 SFP+

The enhanced small form-factor pluggable (SFP+) isan enhanced version of the SFP that supports data ratesup to 16 Gbit/s. The SFP+ specification was first pub-lished on May 9, 2006, and version 4.1 published on July6, 2009.[10] SFP+ supports 8Gbit/s Fibre Channel, 10Gi-gabit Ethernet and Optical Transport Network standardOTU2. It is a popular industry format supported by manynetwork component vendors.Although the SFP+ standard does not include mention of16G Fibre Channel it can be used at this speed.[11] Be-sides the data rate, the big difference between 8G Fibre

1

Page 2: Small Form-factor Pluggable Transceiver

2 9 DIGITAL DIAGNOSTICS MONITORING

Channel and 16G Fibre Channel is the encoding method.64b/66b encoding used for 16G is a more efficient en-coding mechanism than 8b/10b used for 8G, and allowsfor the data rate to double without doubling the line rate.The result is the 14.025 Gbit/s line rate for 16G FibreChannel.In comparison to earlier XENPAK or XFP modules,SFP+ modules leave more circuitry to be implementedon the host board instead of inside the module.[12]

Consideration has to be given to whether the module islinear or limiting. Linear SFP+ modules are most appro-priate for 10GBASE-LRM; otherwise, limiting modulesare preferred.[13]

SFP+ also introduces Direct Attach for connecting twoSFP+ ports without dedicated transceivers.

3 Compatibility

It is possible to design an SFP+ slot that can accept a stan-dard SFP module.[14][15]

4 Applications

Ethernet switch with empty SFP slots (lower left)

SFP sockets are found in Ethernet switches, routers,firewalls and network interface cards. Storage inter-face cards, also called HBAs or Fibre Channel storageswitches, also make use of these modules, supporting dif-ferent speeds such as 2Gb, 4Gb, and 8Gb. Because oftheir low cost, low profile, and ability to provide a con-nection to different types of optical fiber, SFP providessuch equipment with enhanced flexibility.

5 Standardization

The SFP transceiver is not standardized by any officialstandards body, but rather is specified by a multi-sourceagreement (MSA) among competing manufacturers. TheSFP was designed after the GBIC interface, and allowsgreater port density (number of transceivers per cm alongthe edge of a mother board) than the GBIC, which is whySFP is also known asmini-GBIC. The related Small FormFactor transceiver is similar in size to the SFP, but is sol-dered to the host board as a through-hole device, ratherthan plugged into an edge-card socket.

However, as a practical matter, some networking equip-ment manufacturers engage in vendor lock-in prac-tices whereby they deliberately break compatibility with“generic” SFPs by adding a check in the device’s firmwarethat will enable only the vendor’s own modules.[16]

6 Signals

The SFP transceiver contains a PCB that mates with theSFP electrical connector in the host system.

7 Mechanical dimensions

Side view of SFP module (length is 6 cm).

The physical dimensions of the SFP transceiver areslightly smaller than the later XFP transceiver.

8 EEPROM information

The SFP MSA defines a 256-byte memory map into anEEPROM describing the transceiver’s capabilities, stan-dard interfaces, manufacturer, and other information,which is accessible over an I²C interface at the 8-bit ad-dress 1010000X (A0h).

9 Digital diagnostics monitoring

Modern optical SFP transceivers support digital diag-nostics monitoring (DDM) functions according to theindustry-standard SFF-8472. This feature is also knownas digital optical monitoring (DOM). Modules with thiscapability give the end user the ability to monitor pa-rameters of the SFP, such as optical output power, op-tical input power, temperature, laser bias current, andtransceiver supply voltage, in real time.The diagnostic monitoring controller is available as an I²Cdevice at address 1010001X (A2h).

Page 3: Small Form-factor Pluggable Transceiver

3

10 See also• Interconnect bottleneck

• Optical communication

• Optical fiber cable

• Optical interconnect

• Parallel optical interface

• Quad Small Form Factor Pluggable

• Serial digital interface

11 References[1] SFF Committee (2001-05-01), INF-8074i Specification

for SFP (Small Formfactor Pluggable) Transceiver (PDF),retrieved 2012-08-12

[2] Agilestar/Finisar FTLF8524P2BNV specification (PDF)

[3] 1000BASE Gigabit Ethernet SFP Transceiver, Optcore, re-trieved March 26, 2013

[4] https://www.google.com/search?q=GLC-ZX-SM1&rls=com.microsoft:en-za:IE-SearchBox&oe=&um=1&ie=UTF-8&hl=en&tbm=isch&source=og&sa=N&tab=wi&ei=-iADU9axCYfY7AaqkYCwDA

[5] Single Fiber Bidirectional SFP Transceiver (PDF), MRV,retrieved June 16, 2010

[6] Gigabit Bidirectional SFPs, Yamasaki Optical Technology,retrieved June 16, 2010

[7] “Single-fiber single-wavelength gigabit transceivers”.Lightwave. Retrieved September 5, 2002.

[8] “The principle of Single Wavelength BiDi Transceiver”.Gigalight. Retrieved 2011.

[9] VSC8211 media converter/physical layer specification

[10] “SFF-8431 Specifications for Enhanced Small Form Fac-tor Pluggable Module SFP+ Revision 4.1” (PDF). July 6,2009. Retrieved May 9, 2011.

[11] Tektronix (November 2013). “Characterizing an SFP+Transceiver at the 16G Fibre Channel Rate”.

[12] “10-Gigabit Ethernet camp eyes SFP+". LightWave.April 2006.

[13] Ryan Latchman and Bharat Tailor (January 22, 2008).“The road to SFP+: Examining module and system ar-chitectures”. Lightwave. Retrieved July 26, 2011.

[14] SFF-8432, Abstract, Page 1: “Themechanical dimension-ing allows backwards compatibility between IPF mod-ules plugged into most SFP cages which have been im-plemented to SFF-8074i. It is anticipated that when theapplication requires it, manufacturers will be able to sup-ply cages that accept SFP style modules. In both cases theEMI leakage is expected to be similar to that when SFPmodules and cages are mated.”

[15] SFF-8431, Chapter 2 Low Speed Electrical and PowerSpecifications, 2.1 Introduction, Page 4: “The SFP+ lowspeed electrical interface has several enhancements overthe classic SFP interface (INF-8074i), but the SFP+ hostcan be designed to also support most legacy SFP mod-ules.”

[16] John Gilmore. “Gigabit Ethernet fiber SFP slots and lock-in”. Retrieved December 21, 2010.

[17] INF-8074i Specification for SFP (Small Formfactor Plug-gable) Transceiver (PDF), SFF Committee, May 12,2001, p. 6

[18] “INF-8077i: 10 Gigabit Small Form Factor PluggableModule” (PDF). Small Form Factor Committee. August31, 2005. Retrieved June 16, 2011.

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4 12 TEXT AND IMAGE SOURCES, CONTRIBUTORS, AND LICENSES

12 Text and image sources, contributors, and licenses

12.1 Text• Small form-factor pluggable transceiver Source: http://en.wikipedia.org/wiki/Small%20form-factor%20pluggable%20transceiver?oldid=656590102 Contributors: The Anome, Hashar, Mrand, Proteus, Altenmann, Baloo rch, Giftlite, Msiebuhr, Niteowlneils, Hobart, Al-istair1978, Macbandit, Grutness, Thewalrus, Woohookitty, Alecv, TheAnarcat, Srleffler, YurikBot, BertK, Eqvinox, Speculatrix, Smack-Bot, The Photon, Thumperward, Snori, Adamantios, Arkrishna, Kvng, CmdrObot, Epbr123, Kaaveh Ahangar~enwiki, Nick Number,Dawnseeker2000, Ski mountaineer, Dobscure, Somewhere or other, Taborgate, Geekdiva, Jbond00747, VolkovBot, E2550, WinTakeAll,Tomaxer, Steve.lin, Martarius, Eeinmrpk, Alexbot, Richie Campbell, Dgtsyb, Addbot, Stuggi, Tothwolf, MrOllie, SpBot, Jdvillalobos,Luckas-bot, Yobot, Fraggle81, AnomieBOT, Materialscientist, ArthurBot, V35b, Xqbot, Mattg82, W Nowicki, Clamothe, Ckuppireddy,Laugh Tough, Brnsuga99, Sodmy, MurphEngineer, ClueBot NG, Fdleersn, RenaudLavoie, Helpful Pixie Bot, BG19bot, Xizi77, Sallyfiber,Meizidj, Amy dj, Returner323617, ChrisGualtieri, WikiHappytimes, JYBot, Briancarlton, Leaf mei, Hi-tech01, Jeremy Optcore, ShenzhenSourcelight, Filedelinkerbot and Anonymous: 91

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