Reference Guide: Optical Transceivers
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Reference Guide Optical Transceiver Reference Guide For more information, visit commscope.com Contents Overview 3 10/25 Gigabit Ethernet and 8/16/32G Fibre Channel 9 40 Gigabit Ethernet 11 100 Gigabit Ethernet 13 200/400 Gigabit Ethernet 18 Active optical cable 19 Direct attach copper cable 20 On-board optics 21 Appendix22 1. Document revision history 22 2. Pictures of optical transceiver form factors 22 3. Mechanical drawings 23 4. Links for MSAs, alliances or consortiums 26 2 For more information, visit commscope.com Optical Transceiver Reference Guide Overview An optical transceiver is a photonic and electronic device that transmits and receives signals over optical fibers. Two optical transceivers at the ends—with passive fiber cabling in between—construct a network channel. There are questions, confusions or even myths around optical transceivers. Typical ones are: • With so many different transceivers, which one is used for what network application? • What connector type and how many fibers does an optical transceiver use? • Doesn’t a QSFP+ transceiver only use MPO connectors? • Who specifies these optical transceivers—IEEE, TIA/IEC or MSA? Who is MSA? This document summarizes and illustrates optical transceivers in terms of form factor, application (standard, prestandard or proprietary), connector, fiber type and strand count, wavelength, and cable reach with commercially available product as examples. An optical transceiver form factor is specified by a multisource agreement (MSA). An MSA is an agreement between multiple manufacturers to make optical transceivers that can plug into switches. The SFF Committee, CFP-MSA and CDFP-MSA referred to later are examples of MSAs. IEEE 802.3 is the standards body that defines Ethernet network standards. INCITS T11 is the standards body that defines Fiber Channel (storage network) standards. However, neither IEEE nor T11 specifies optical transceivers. IEEE and T11 define the minimum performance requirements that will ensure interoperability. MSAs may adopt these standards to specify optical transceiver implementations. MSAs can also specify nonstandard-based optical transceivers. A networking technology may come to market with multiple choices or generations of optical transceivers. The market will eventually choose the winning solution based on cost, size, power consumption, vendor support, etc. Key acronyms: XFP = 10 Gigabit Small Form Factor Pluggable Module SFP+ = Enhanced small form-factor pluggable SFP28 = 28 Gb/s SFP+ pluggable with the same mechanical design of SFP+ QSFP+ = SFF-8436 quad small form-factor pluggable plus, each lane running up to 10 Gb/s QSFP28 = Mechanical design of QSFP+, each lane running up to 28 Gb/s CXP = 120 Gb/s 12-lane small form-factor pluggable CFP = C-form factor pluggable CFP2 and CFP4 = Next generations of CFP CPAK™ = Cisco’s proprietary 100 Gigabit Ethernet pluggable transceiver modules CDFP = 400 Gb/s form-factor pluggable, 16 lanes each running up to 25 Gb/s 3 For more information, visit commscope.com Optical Transceiver Reference Guide The table summarizes optical transceiver, image, specification name and typical applications. Form factor Image XFP MSA specification XFP MSA Applications 10GE Image Source: Finisar SFF-8431 (electrical) SFF-8432 (mechanical) SFF Committee SFP+ 10GE, 8/10/16/32G FC Image Source: Finisar SFP28 SFF-8402 (electrical) SFF-8432 (mechanical) SFF-8472 (diagnostic) 25GE SFF-8436 SFF Committee 40GE Image Source: Finisar QSFP+ Image Source: Finisar 100GE, 4x25GE, 128GFC, 4x32GFC* SFF-8665 SFF Committee QSFP28 *Note: 128GFC and 32GFC operate at 28 Gb/s per lane. Image Source: Finisar IBTA’s CXP InfiniBand Trade Association http://www.infinibandta.org/ CXP 10x10GE, 12x10GE, 100GE, 3x40GE Image Source: Finisar 4 For more information, visit commscope.com Optical Transceiver Reference Guide CFP CFP MSA www.cfp-msa.org 100GE, 40GE CFP MSA CFP2 hardware specification www.cfp-msa.org 100GE CFP MSA CFP4 hardware specification www.cfp-msa.org 100GE Cisco proprietary 100GE CDFP-MSA 400GE, 16X25GE CFP MSA www.cfp-msa.org 400GE, 4x100GE Image Source: Finisar CFP2 Image Source: Finisar CFP4 Image Source: Finisar CPAK Image Source: Finisar CDFP Image Source: Finisar CFP8* Image Source: Finisar Note: 1. There are other form factors—such as SFP (same mechanical design of SFP+ but for 1GE), XENPAK (for 10GE), and QSFP (same mechanical design of QSFP+). These form factors are earlier generations. Because they are either being phased out or have insignificant market share, this document will not include them. 2. The optical form factors are used in InfiniBand (IB) applications as well. IB is a networking technology different from Ethernet or Fiber Channel. IB has less than 5 percent share of total networking market. In order to not lose focus, IB applications are not included in the document. 3. Both CDFP and CFP8 are in development 5 For more information, visit commscope.com Optical Transceiver Reference Guide The table summarizes types of connectors and fiber used in optical transceiver form factors. Form factor LC, 2 SMF LC, 2 MMF XFP SFP+ SFP28 QSFP+ QSFP28 SC, 2 SMF SC, 2 MMF 12f MPO, SMF 12f MPO, MMF 24f MPO, SMF CXP 24f MPO, MMF MPO-16, SMF MPO-16, MMF CPAK™ CFP CFP2 CFP4 CDFP Note: 1. A check () means, “Yes, the type of connector and fiber are used in the form factor for an application.” The aqua-colored check () indicates multimode while the yellow-colored check () indicates singlemode. 2. A blank means, “The connector and fiber are not seen used in the form factor.” 3. A dark gray-shaded cell indicates connector mechanical incompatibility (e.g., too large) with form factor. 4. A light gray-shaded cell indicates a pointless connector due to optical lane count far exceeding electrical lane counts, or number of optical fiber rows larger than the form factor can use. 5. The MPO-16 has two variants: 16-fiber MPO-16 and 32-fiber MPO-16. 6. Both CDFP and CFP8 are in development 6 For more information, visit commscope.com Optical Transceiver Reference Guide Connector on transceiver Lane assignment Duplex LCs (SMF or MMF) on SFP+/SFP28/QSFP+/QSFP 28/CFP/CFP2/CFP4/CDFP When looking into the LC receptacle 12f MPO (SMF or MMF) on QSFP+/QSFP28/CFP/ CFP2/CFP4 When looking into the MPO receptacle Note: The four fibers in the middle are not used Image source: Finisar 24f MPO (MMF) on CXP When looking into the MPO receptacle Image source: IBTA CXP specification 7 For more information, visit commscope.com Optical Transceiver Reference Guide 24f MPO (MMF) on CFP/CFP2/CFP4 When looking into MPO receptacle Note: Fibers 1, 12, 13 and 24 are not used for 100GE Image source: IBTA CXP specification MPO-16 When looking into MPO receptacle Note: 1. Proposed connectors and lane assignment for 400GE over multimode. 2. The MPO-16 has two variants. They are the 16 fiber MPO-16 and 32 fiber MPO-16. Source: CDFP-MSA specification 3.0 8 For more information, visit commscope.com Optical Transceiver Reference Guide 10/25 Gigabit Ethernet and 8/16/32G Fibre Channel The IEEE 802.3by 25GE standard is technically complete and expected to be ratified in 2016. The SFP28 has been standardized by the SFF Committee for 25GE. SFP+ form factor Application Connector and fiber Cabling reach 10GBASE-ZR LC receptacles duplex (2) SMF 1550nm 80 kilometers on SMF 10GBASE-SR LC receptacles duplex (2) MMF 850 nm 300 meters on OM3 400 meters on OM4 10GBASE-LR LC receptacles duplex (2) SMF 1310 nm 10 kilometers on SMF 10GBASE-ER LC receptacles duplex (2) SMF 1550 nm 40 kilometers on SMF 25GBASE-SRSFP28 prestandard LC receptacles duplex (2) MMF 850 nm 70 meters on OM3 100 meters on OM4 25GBASE-SR prestandard LC receptacles duplex (2) MMF 850 nm 70 meters on OM3 100 meters on OM4 XFP Finisar FTLX1812M3BNL Finisar FTLX8571D3BCL (< 1 watt) Finisar FTLX1471D3BCL (< 1 watt) Finisar FTLX1672D3BCL (< 1 watt) SFP28 Finisar FTLF8536P4BCL SFP28 Avago AFBR-725SMZ 9 For more information, visit commscope.com Optical Transceiver Reference Guide 25GE long-wavelength SFP+ nonstandard LC receptacles duplex (2) SMF 1310 nm 2 kilometers on SMF 8G FC LC receptacles duplex (2) SMF 1310 nm 10 kilometers on SMF 8G FC LC receptacles duplex (2) MMF 850 nm 16G FC LC receptacles duplex (2) MMF 850 nm 16G FC LC receptacles duplex (2) SMF 1310 nm 32G FC LC receptacles duplex (2) MMF 850 nm Finisar FTLF1436P3BCL Finisar FTLF1428P2BNV 150 meters on OM3 190 meters on OM4 Finisar FTLF8528P3BCV (< 0.5 watts) 100 meters on OM3 125 meters on OM4 Finisar FTLF8529P3BCV 10 kilometers on SMF Finisar FTLF1429P3BNV (< 1 watt) 70 meters on OM3 100 meters on OM4 Finisar FTLF8532P4BCV 32G FC LC receptacles duplex (2) SMF 1310 nm 10 kilometers on SMF Finisar FTLF1432P3BCV (1 watt) Note: the products listed in the table are for illustration purpose. 10 For more information, visit commscope.com Optical Transceiver Reference Guide 40 Gigabit Ethernet The 40GE transceiver market is dominated by the QSFP+ form factor. The 40GE in CFP has insignificant market share. QSFP+ form factor Application Connector and fiber Cabling reach 40GBASE-SR4 12f MPO, pinned parallel MMF 4-fiber Tx, 4-fiber Rx 850 nm 100 meters on OM3, 150 meters on OM4 40GE proprietary 12f MPO, pinned parallel MMF 4-fiber Tx, 4-fiber Rx 850 nm 300 meters on OM3, 400 meters on OM4 Cisco QSFP-40G-SR4 (< 1.5 watts) Avago QSFP+ 3SR4 AFBR-79E3PZ (< 1.5 watts) LC receptacles duplex (2) MMF bidirectional each fiber 832–918 nm 40GE proprietary 100 meters on OM3, 150 meters on OM4 Cisco “BiDi” QSFP-40G-SR-BD (< 3.5 watts) 40G SWDM4 proprietary in preproduction LC receptacles duplex (2) MMF 850–950 nm, 4λx10G SWDM TBD on OM3/4, TBD on WBMMF 40GBASE-LM4 multimode “adaptation of IEEE 802.3ba 40GBASE-LR4 referred to as LM4” Proprietary LC receptacles duplex (2) MMF 1264.5–1337.5nm, 4λx10G CWDM 140 meters on OM3, 160 meters on OM4 40GBASE-LR4 Lite Nonstandard LC receptacles duplex (2) SMF 1310 nm, 4λx10G WDM 2 kilometers on SMF 40G SWDM4 QSFP+ Image source: SWDM.org Finisar FTL4C2QE1C (< 3.5 watts) Cisco WSP-Q40GLR4L (< 3.5 watts) (w/ yellow pull tab) 11 For more information, visit commscope.com Optical Transceiver Reference Guide 40GBASE-LR4 LC receptacles duplex (2) SMF 1310 nm, 4λx10G WDM 10 kilometers on SMF 4x10GBASE-LR Lite and 4x10GBASE-LR Both proprietary 12f MPO, pinned parallel SMF, 4-fiber Tx, 4-fiber Rx 1310 nm Use fan-out arrays to four 10GBASE-LR 2 kilometers on SMF Lite (FTL4P1QL1C) and 10 kilometers on SMF 40GBASE-ER4 LC receptacles duplex (2) SMF 1310 nm, 4λx10G WDM 40 kilometers on SMF Cisco QSFP-40GE-LR4 (< 3.5 watts) (w/ blue pull tab) Finisar FTL4P1QL1C (< 2.5 watts) Finisar FTL4E1QE1C (< 3.5 watts) 40GE universal transceiver (QSFP+) Proprietary LC receptacles duplex (2) either MMF or SMF 1270–1330 nm, 4λx10G WDM 150 meters on OM3/OM4 or 500 meters on SMF Arista QSFP-40G-UNIV transceiver (< 3.5 watts) CFP 40GBASE-SR4 in CFP 12f MPO, pinned parallel MMF, 4-fiber Tx, 4-fiber Rx 850 nm 40GBASE-FR in CFP LC receptacles duplex (2) SMF 1550 nm, 4λx10G WDM 100 meters on OM3 150 meters on OM4 Finisar FTLQ8181EBLM (< 6 watts) CFP 2 kilometers on SMF Finisar FTLQ1381N7NL (< 8 watts) Note: 1. The products listed in the table are for illustration purpose. 2. The “WDM” stands for wavelength division multiplexing and “λ” represents wavelength. 12 For more information, visit commscope.com Optical Transceiver Reference Guide 100 Gigabit Ethernet Unlike 40GE, 100GE optical transceivers have a number of form factors, such as CFP/CFP2/CFP4, CXP and QSFP28. The letter “C” in CFP/CFP2/CFP4 and CXP stands for 100, as used in “centum.” The 100GE transceiver form factor started with CFP and CXP. New generations of 100GE optical transceivers are in CFP4 and QSFP28. It appears that the market has chosen the QSFP28 as the primary form factor for 100GE. The 100GE optical transceiver market is fragmented by many different implementations. In addition to the IEEE standards, there are more than eight MSAs that have developed or are developing 100GE transceivers. Specification Group Connector and fiber Cabling reach 100GBASE-SR10 IEEE 24f MPO, pinned parallel MMF 10-fiber Tx, 10-fiber Rx 850 nm 100 meters on OM3 150 meters on OM4 100GBASE-LR4 IEEE LC receptacles duplex (2) SMF 1310 nm, 4λx25G WDM 10 kilometers on SMF 100GBASE-ER4 IEEE LC receptacles duplex (2) SMF 1310 nm, 4λx25G WDM 40 kilometers on SMF 100GBASE-SR4 IEEE 12f MPO, pinned parallel MMF 4-fiber Tx, 4-fiber Rx 850 nm 100 meters on OM4 100G SWDM4 SWDM Alliance (preproduction) LC, receptacles duplex (2) MMF 850–950 nm, 4λx25G SWDM 100G CLR4 100G CLR4 Alliance LC receptacles duplex (2) SMF 1271–1331 nm, 4λx25G CWDM 2 kilometers on SMF 100G CWDM4 CWDM4 MSA LC receptacles duplex (2) SMF 1271–1331 nm, 4λx25G CWDM 2 kilometers on SMF 100G PSM4 100G PSM4 MSA 12f MPO, pinned parallel SMF 4-fiber Tx, 4-fiber Rx 1310 nm 500 meters on SMF 100G 10x10WDM 10x10 MSA LC receptacles duplex (2) SMF 1523–1595 nm, 10λx10G WDM 2 kilometers, 10 kilometers or 40 kilometers on SMF TBD on OM3/4 TBD on WBMMF Note: TIA(R) Engineering Committee TR-42 has ratified WBMMF specifications. Therefore WBMMF has been officially standardized. 13 For more information, visit commscope.com Optical Transceiver Reference Guide The following table lists examples of 100GE optical transceivers, applications and corresponding cabling information. Form factor Application Connector and fiber Cabling reach 100GBASE-LR4 in CFP LC or SC receptacles duplex (2) SMF 1310 nm, 4λx25G WDM 10 kilometers on SMF 100GBASE-LR4 in CFP SC receptacles duplex (2) SMF 1310 nm, 4λx25G WDM 10 kilometers on SMF 100GBASE-ER4 in CFP SC receptacles duplex (2) SMF 1310 nm, 4λx25G WDM 40 kilometers on SMF 10x10 MSA in CFP LC receptacles duplex (2) SMF 1523–1595 nm, 10λx10G WDM 10 kilometers on SMF 100GBASE-SR10 in CFP 24f MPO, pinned parallel MMF 10-fiber Tx, 10-fiber Rx 850 nm Also, ribbon-to-duplex-fiber breakout cables to ten 10GBASE-SR CFP Finisar FTLC1183RDNx CFP Cisco CFP-100G-LR4 (< 24 watts) CFP Cisco CFP-100G-ER4 (< 24 watts) CFP Oplink CFP1C0XL2C000E1G CFP Cisco CFP-100G-SR10 (< 12 watts) 100 meters on OM3, 150 meters on OM4 CFP2 100GBASE-SR10 in CFP2 and 100GBASE-SR10 extended reach in CFP2 24f MPO, pinned parallel MMF 10-fiber Tx, 10-fiber Rx 850 nm Finisar FTLC8221RFNM (< 4 watts) 14 100 meters on OM3, 150 meters on OM4 and extended reach 300 meters on OM3, 400 meters on OM4 For more information, visit commscope.com Optical Transceiver Reference Guide CFP2 100GBASE-LR4 in CFP2 LC receptacles duplex (2) SMF 1310 nm, 4λx25G WDM 10 kilometers on SMF 100GBASE-LR4 in CFP4 LC receptacles duplex (2) SMF 1310 nm, 4λx25G WDM 10 kilometers on SMF 100GBASE-SR4 in CFP4 12f MPO, pinned parallel MMF 4-fiber Tx, 4-fiber Rx 850 nm 70 meters on OM3 100 meters on OM4 100GBASE-SR4 in QSFP28 12f MPO, pinned parallel MMF 4-fiber Tx, 4-fiber Rx 850 nm 70 meters on OM3 100 meters on OM4 100GBASE eSR4 proprietary in QSFP+ 12f MPO, pinned parallel MMF 4-fiber Tx, 4-fiber Rx 850 nm 200 meters on OM3 300 meters on OM4 100GE SWDM4 proprietary in QSFP28 preproduction LC receptacles duplex (2) MMF 850–950 nm, 4λx25G SWDM TBD on OM3/4 TBD on WBMMF Finisar FTLC1121RDNL (< 8 watts) CFP4 Finisar FTLC1141RDNL (< 5 watts) CFP4 FTLC9141RENM (< 4 watts) QSFP28 Finisar FTLC9551REPM (< 3.5 watts) QSFP28 Avago AFBR-89CEDZ 100G QSFP28 SWDM4 Image source: SWDM.org 15 For more information, visit commscope.com Optical Transceiver Reference Guide QSFP28 100GE CWDM4 in QSFP28 LC receptacles duplex (2) SMF 1310 nm, 4λx25G CWDM 2 kilometers on SMF 100GBASE-LR4 in QSFP28 LC receptacles duplex (2) SMF 1310 nm, 4λx25G WDM 10 kilometers on SMF 12f MPO, pinned parallel SMF 4-fiber Tx, 4-fiber Rx 1310 nm 2 kilometers on SMF LC receptacles duplex (2) SMF 1310 nm, 4λx25G CWDM 2 kilometers on SMF SC receptacles duplex (2) SMF 1310 nm, 4λx25G WDM 10 kilometers on SMF SC receptacles duplex (2) SMF 1310 nm, 4λx25G WDM 25 kilometers on SMF Finisar FTLC1152RGPL (< 3.5 watts) QSFP28 Finisar FTLC1151RDPL (< 3.5 watts) QSFP28 100GE PSM4 MSA in QSFP28 Luxtera LUX42604 QSFP QSFP28 100GE CLR4 MSA Kaiam XQX4000 100G-CLR4/CWDM4 QSFP28 CPAK 100GBASE-LR4 in Cisco’s proprietary “CPAK” using silicon photonics Cisco CPAK 100GBASE-LR4 (< 6.75 watts) CPAK 100GBASE-ER4 Lite in Cisco’s proprietary “CPAK” Cisco CPAK-100G-ER4L (< 7.5 watts) 16 For more information, visit commscope.com Optical Transceiver Reference Guide CPAK 24f MPO, pinned parallel SMF 10-fiber Tx, 10-fiber Rx 1310 nm Also, ribbon-to-duplex SMF breakout cables to ten 10GBASE-LR 10 kilometers on SMF 100GBASE-SR10 in Cisco’s proprietary “CPAK” 24f MPO, pinned parallel MMF 10-fiber Tx, 10-fiber Rx 850 nm; Also, ribbon-to-duplex-fiber breakout cables to ten 10GBASE-SR 100 meters on OM3, 150 meters on OM4 12 x 10GE in CXP 24f MPO, pinned parallel MMF 12-fiber Tx, 12-fiber Rx 850 nm Also, breakout to 12x 10GBASE-SR 100 meters on OM3 150 meters on OM4 and 300 meters on OM3 400 meters on OM4 (Finisar FTLD10CD3C extended reach) 10x10GBASE-LR in Cisco’s proprietary “CPAK” using silicon photonics Cisco CPAK 10x10GBASE-LR (< 4.5 watts) CPAK Cisco CPAK 100GBASESR10 (< 4.5 watts) CXP Finisar FTLD10CE3C (< 3.5 watts) Note: 1. The products listed in the table are for illustration purpose. 2. The “WDM” stands for wavelength division multiplexing and “λ” represents wavelength. 3. The “SWDM” standards for shortwave wavelength division multiplexing. 4. The “CDWM” standards for coarse wavelength division multiplexing. 17 For more information, visit commscope.com Optical Transceiver Reference Guide 200/400 Gigabit Ethernet The IEEE802.3bs task force is developing the 400GE standard. The CDFP-MSA has released the Rev. 3.0 for a CDFP transceiver that can support 400GE with 16 lanes and each lane running at 25 Gb/s. The CFP8 was proposed by the CFP MSA in July 2015 and is being under development to support 400GE as well. The QSFP-DD Multi-Source Agreement (MSA) Group was announced in March 2016. The MSA plans to develop double-density quad small form factor pluggable (QSFP-DD) interfaces. The QSFP-DD pluggable form factor will employ eight lanes that operate up to 25 Gb/s NRZ modulation or 50 Gb/s PAM4 modulation, providing solutions up to 200 Gb/s or 400 Gb/s aggregate. Form factor Application Connector and fiber Cabling reach 200GE and 400GE TBD TBD QSFP-DD Image source: QSFP-DD MSA CDFP 400GE prestandard in CDFP Molex zCD active optical cable (AOC) CDFP 400GE prestandard In CDFP * Note: This is an AOC (not a discrete optical transceiver) using SMF cable. There is no user-accessible fiber connector. * Note: This is an AOC (not a discrete optical transceiver) using MMF cable. There is no user-accessible fiber connector. TE CDFP active optical cable assembly (6 watts per end) Molex offers up to 4 kilometers on SMF TE offers up to 100 meters on MMF 850 nm CFP8 400GBASE-FR8/LR8 pre-standard in CFP8 LC receptacles duplex (2) SMF 1310nm, 8λx50G WDM 10 kilometers on SMF NeoPhotonics 400G CFP8 transceiver PT-C88F3XECL Note: An active optical cable (AOC) is a fiber cable preterminated with two optical transceivers at the ends. An AOC is a closed network channel. The products listed in the table are for illustration purpose. 18 For more information, visit commscope.com Optical Transceiver Reference Guide Active optical cable When a fiber cable is preterminated with an optical transceiver at each end, the assembly becomes an active optical cable (AOC). The application an AOC supports depends on the type of optical transceivers it has. Because an AOC constructs a network channel from end to end, it doesn’t have any fiber connector interface accessible by users, and its fiber type (SMF vs. MMF) carries less significance. The popular AOC form factors are listed in the following table. AOC form factor Application Connector and fiber Cabling reach 10GE No connector interface Finisar SFP+ AOC lengths available up to 20 meters 10GE No connector interface Cisco currently offers active optical breakout cables in lengths of 1, 2, 3, 5, 7, and 10 meters 40GE No connector interface Cisco currently offers active optical cables in lengths of 1, 2, 3, 5, 7, 10, and 15 meters 100GE, InfiniBand 4x enhanced data rate (EDR), 4x32G Fiber Channel No connector interface Not available yet Finisar SFP+ to SFP+ AOC FCBG110SD1Cxx Cisco 40G QSFP to four SFP+ breakout active optical cables Cisco QSFP to QSFP active optical cables Finisar 100G Quadwire® QSFP28 to QSFP28 AOC MPO pinned parallel SMF (PSM4) 40GE, InfiniBand quad data rate (QDR) Molex QSFP+ to MPO pigtail cable 4-fiber Tx and 4-fiber Rx 4 kilometers on SMF Required structured fiber cabling system Note: The cable reach of AOCs varies across vendor. The products listed in the table are for illustration purpose. The cabling reach information listed in the tables is sourced from corresponding product’s information sheet or from MSA’s specifications. 19 For more information, visit commscope.com Optical Transceiver Reference Guide Direct attach copper cable The copper counterpart of AOC is direct attach copper cable (DAC). Although DACs have the same mechanical packages as optical transceivers, DACs don’t have equivalent electronic circuits of optical transceivers. Many DACs actually are passive copper twinax cable assemblies. Most DACs are deployed to connect servers to top-of-rack switches within the same rack/cabinet. The popular DAC form factors are listed in the following table. DAC form factor Application Twinax cable Cabling reach 2 wires of twinax cable Cisco offers passive twinax cables in lengths of 1, 1.5, 2, 2.5, 3, and 5 meters, and active twinax cables in lengths of 7 and 10 meters 8 wires of twinax cable Cisco offers passive cables in lengths of 1, 3, and 5 meters and active cables in lengths of 7 and 10 meters 40GE 8 wires of twinax cable Cisco offers passive cables in lengths of 1, 3, and 5 meters and active cables in lengths of 7 and 10 meters 25GE 2 wires of twinax cable Cisco offers passive cables in lengths of 1, 2, 3, and 5 meters 100GE (4x25Gbps) and InfiniBand EDR 8 wires of twinax cable Length information not available 10GE Cisco SFP+ DACs 10GE Cisco QSFP to 4 SFP+ DACs Cisco QSFP+ DACs Cisco SFP28 DACs TE QSFP28 passive DAC Note: The cable reach of DACs varies across vendors. The products listed in the table are for illustration purpose. The cabling reach information listed in the tables is sourced from corresponding product’s information sheet or from MSA’s specifications. 20 For more information, visit commscope.com Optical Transceiver Reference Guide On-board optics Optical transceivers can be built directly on the motherboard of a network switch. In the case of on-board optics, network administrators don’t need to install optics and they only need to plug cables with proper connectors directly into the switch. The Consortium for On-Board Optics (COBO) is a member-driven standards-setting organization developing specifications for interchangeable and interoperable optical modules that can be mounted onto printed circuit boards. The MXP ports on Arista switches are examples of on-board optics. An Ethernet switch line card with MXP ports is shown in the figure below. Since transceivers are already built on the motherboard of the line card, network admins can plug a cable with a proper connector. The connector acceptable by on-board optics can be various. The MXP ports of Arista switches can have three modes to support 10/40/100G over multimode fiber cabling. The connector the MXP port accepts is 24-fiber MPO as described in the earlier section. Image source: Arista 21 For more information, visit commscope.com Optical Transceiver Reference Guide Appendix 1. Document revision history Date Version # Descriptions By 6/3/2015 V1.0 Initial version Frank Yang V2.0 Add: SFP28 and QSFP28 form factors; 40/100GE SWDM4; 100G CLR4, CWDM4; on-board optics; QSFP-DD for 200/400G; CFP8 form factor and editorial changes Frank Yang 5/31/2016 2. Pictures of optical transceiver form factors Generations of CFPx form factor Cisco’s CPAK modules (middle two) along with its QSFP+ modules 22 For more information, visit commscope.com Optical Transceiver Reference Guide 3. Mechanical drawings Form factor Drawing example SFP+ Image source: Finisar SFP28 Same as SFP+ QSFP+ Dimensions are in millimeters Image source: Finisar 23 For more information, visit commscope.com Optical Transceiver Reference Guide CXP Dimensions are in millimeters Image source: Finisar Drawing not found yet CPAK Maximum outer dimensions for the Cisco CPAK modules (H x W x D): 11.6 x 34.8 x 101.2 mm (0.46 x 1.37 x 3.98 in). Drawing not found yet CFP Cisco CFP dimensions (D x W x H): 144.8 x 82 x 13.6 mm 24 For more information, visit commscope.com Optical Transceiver Reference Guide CFP2 Dimensions are in millimeters Image source: Avago CFP4 Dimensions are in millimeters Image source: Finisar 25 For more information, visit commscope.com Optical Transceiver Reference Guide QSFP28 Same mechanical design as QSFP+ CDFP Source: CDFP-MSA specification Rev. 3.0 4. Links for MSAs, alliances or consortiums SFF Committee http://www.sffcommittee.com/ie/index.html CFP/CFP2/CFP4 http://www.cfp-msa.org CDFP MSA http://www.cdfp-msa.com/ 100G CLR4 Alliance https://www.clr4-alliance.org/ SWDM Alliance http://www.swdm.org/ CWDM4 MSA http://www.cwdm4-msa.org/ 100G PSM4 MSA http://www.psm4.org/ 10x10 MSA http://10x10msa.blogspot.com/ QSFP-DD MSA http://www.qsfp-dd.com/ Consortium for On-Board Optics (COBO) http://cobo.azurewebsites.net/ 26 For more information, visit commscope.com Optical Transceiver Reference Guide 27 For more information, visit commscope.com www.commscope.com Visit our website or contact your local CommScope representative for more information. © 2016 CommScope, Inc. All rights reserved. All trademarks identified by ® or ™ are registered trademarks or trademarks, respectively, of CommScope, Inc. This document is for planning purposes only and is not intended to modify or supplement any specifications or warranties relating to CommScope products or services. TP-110307.1-EN (07/16)
