40G QSFP+ Module and CFP Module Wiki
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40G QSFP+ Module and CFP Module Wiki

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A transceiver module is a self-contained component that can both transmit and receive analog or digital signals. The transceiver acts to connect the electrical circuitry of the module with the optical or copper network. The optical fiber, or wire, plugs into a connector on the transceiver module. Devices such as routers or network interface cards provide one or more transceiver module slot (like GBIC, SFP, XFP) into which you can insert a transceiver module which is appropriate for that connection. There are multiple types of transceiver module available for use with different types of wire, fiber, different wavelengths within a fiber, and for communication over different distances. The following of the post is a brief introduction to 40G QSFP+ module and CFP module.

What Is QSFP+?

The 40GBASE QSFP+ (quad small form-factor pluggable plus) modules offer customers a wide variety of high-density 40 Gigabit Ethernet connectivity options for data center, high-performance computing networks, enterprise core and distribution layers, and service provider transport applications.

FS.COM 40G QSFP+ modules

40G QSFP+ modules support four separate 10G channels to simultaneously operating for supplying 40 Gigabit Ethernet, or four channels combined into one single 40GbE channel. Nowadays, high-speed direct attach cables can also be pre-terminated with QSFP+ modules as a cost-effective cabling choice. 40G QSFP+ transceivers support protocols including but not limited to: 40GBASE-SR4, 40GBASE-LR4, 40GBASE-BiDi, 40GBASE-ER4, 40GBASE-LRL4, 40GBASE-PLRL4, 40GBASE-FR, 40GBASE-T, etc. These 40G QSFP+ transceivers operate with different transfer mediums (copper or optical fiber) and are designed with different interfaces (duplex LC or parallel MTP/MPO) to support various maximum transmission lengths. The following table are specifications for some 40G QSFP+ modules.

Transceiver Type Specification
40GBASE-SR4 100 m over OM3 MMF, MTP/MPO
150 m over OM4 MMF, MTP/MPO
40GBASE-LR4 10 km over SMF, LC Duplex
40GBASE-ER4 40 km over SMF, LC Duplex
40GBASE-LRL4 1 km over SMF, LC Duplex
40GBASE-PLRL4 1 km over SMF, MTP/MPO
40GBASE-FR 2 km over SMF, serial
40GBASE-T 30 m over Cat.8 twisted pair
40GBASE-CR4 7 m over twinax copper cable
40GBASE-KR4 Improved Backplane
What Is CFP?

CFP stands for C form-factor pluggable. It is a multi-source agreement to produce a common form-factor for the transmission of high-speed digital signals. The c stands for the Latin letter C used to express the number 100 (centum), as the standard was primarily developed for 100 Gigabit Ethernet systems. In practice the CFP MSA defines hot-pluggable optical transceiver form factors to enable both 40Gb/s and 100Gb/s applications, including next-generation High Speed Ethernet (40GbE and 100GbE). Pluggable CFP, CFP2 and CFP4 transceivers will support the ultra-high bandwidth requirements of data communications and telecommunication networks that form the backbone of the Internet.


While the electrical connection of a CFP uses 10 x 10 Gbit/s lanes in each direction (RX, TX), the optical connection can support both 10 x 10 Gbit/s and 4 x 25 Gbit/s variants of 100 Gbit/s interconnects, typically referred to as 100GBASE-LR10 and 100GBASE-LR4 in 10 km reach, and 100GBASE-ER10 and 100GBASE-ER4 in 40 km reach respectively. Other CFP types are also used, like CFP-SR10-100G, CFP-LR4-40G, etc.


After reading this article you may get some basic information about 40G QSFP+ module and CFP module. If you are in need of any of these compatible modules, do not hesitate to contact FS.COM about the product details or technical questions. We are devoted to make quality compatible and generic transceiver modules and provide best service to our customers.

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