40G Transceiver Module: QSFP+ Module And CFP Module
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40G Transceiver Module: QSFP+ Module And CFP Module

Posted on by FS.COM

With the advancement of Gigabit Ethernet, high-speed optical transceiver module that emerging markets are increasingly demanding. The key driver is the upgrading of international large data centers. The new demands of 40G transceiver modules pushed the high-speed optical transceiver market to grow. This article would put emphasis on introducing 40G transceiver module, especially the QSFP+ module and CFP module.

40G QSFP+ transceiver modules

What’s 40G QSFP+ Module?

The 40GBASE QSFP+ (quad small form-factor pluggable plus) module is a hot-swappable, parallel fiber optical module with 4 independent 10 gigabit per second data lanes in each direction to provide 40Gbps aggregate bandwidth. The QSFP+ optics fully conforms to the QSFP MSA standard. According to QSFP standard, 40G QSFP+ connector can be either duplex LC or 12-fiber MTP/MPO connector. 40G QSFP+ 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.

How Many Types of 40G QSFP+ Module?

According to different Ethernet protocols, QSFP+ 40G transceiver modules can be divided into singlemode QSFP+ and multimode QSFP+. Singlemode QSFP+ transceiver modules can be further divided into 40GBASE-PLRL4, 40GBASE-LR4L, 40GBASE-LR4 and etc. The singlemode QSFP+ transceiver is designed for long-haul transmission, and the maximum transmission can be up to 40km via 40GBASE-ER4 QSFP module. Multimode QSFP+ transceiver modules are mainly used for transmission data within near areas. Transmission distance is varied from 100m to 400m. The detailed specification of QSFP+ 40G transceiver is described in the below table.

Type Wavelength(nm) Fiber Type Connector Type Max Transmission Length
40GBASE-CSR4 850 MMF MTP/MPO 400m
40GBASE-SR4 850 MMF MTP/MPO 150m
40GBASE-SR BiDi 832-918 MMF LC 150m
40GBASE-PLRL4 1310 SMF MTP/MPO 1.4km
40GBASE-LR4L 1310 SMF LC 2km
40GBASE-LX4 1310 SMF LC 2km
40GBASE-LR4 1310 SMF LC 10km
40GBASE-PLR4 1310 SMF MTP/MPO 10km
40GBASE-ER4 1310 SMF LC 40km

Common Questions About 40G Transceiver Module

Q: What are the differences between MTP/MPO interface & LC interface 40G QSFP+ transceivers?

A: As a rule, the 40G QSFP+ transceivers with LC interface are used for long-haul transmission over singlemode fiber (SMF), and those with MTP/MPO interface (except for 40GBASE-PLRL4 and 40GBASE-PLR4) are applied for short distance transmission via multimode fiber (MMF). Besides, 40G QSFP+ transceiver with MTP/MPO interface can be used in 4x10G connectivity via breakout cable, while 40G QSFP+ transceiver with LC interface cannot be slit into 4x10G as they use 4 wavelengths on a pair of singlemode fiber.

Q: Which 40G QSFP+ transceivers can be used for 4x10G?

A: As 40GBase-SR4, 40Gbase-CSR4, 40GBASE-PLR4 and 40GBASE-PLRL4 interface with MTP/MPO connector, so they are the four 40G transceiver modules which can be used for 4 x 10G connectivity. That is achieved by using an external 12-fiber parallel to 2-fiber duplex breakout cable, which connects the 40GBASE-SR4/40Gbase-CSR4 module to four 10GBASE-SR optical interfaces. 40GBASE-PLR4/40GBASE-PLRL4 module can be used in a 4x10G breakout mode with parallel to duplex fiber breakout cables for connectivity to four 10GBASE-LR interfaces.

40G QSFP+ transceivers used for 4x10G

Q: How to choose the right fiber optic cable for the 40G QSFP+ transceiver?

A: When selecting proper fiber patch cable for 40G QSFP+ transceiver, cable types, cable connectors, and ports of the switches attach great importance. Generally, here comes two cabling solutions for 40G QSFP+ transceiver, 40G QSFP+ to 40G QSFP+ cabling and 40G QSFP + to 10G SFP + cabling.

40G QSFP+ to 40G QSFP+ cabling options:

 a. For distance under 150m, the 40GBASE-SR4 QSFP+ transceiver can be used with OM4 fiber patch cable terminated with MTP/MPO connector on each end.
 b. For the distance between 300m and 400m, the 40GBASE-CSR4 QSFP+ modules can be utilized with OM3 and OM4 fiber patch cables ended with MTP/MPO connector.
 c. When distance amounts to or exceeds 2km, 40GBASE-LR4L, 40GBASE-LX4, 40GBASE-PLR4, 40GBASE-LR4 as well as 40GBASE-ER4 can be used. 40GBASE-LR4L/40GBASE-LX4 is for 2km, 40GBASE-LR4/40GBASE-PLR4 for 10km, and 40GBASE-ER4 for 40km.
40G QSFP+ cabling

40G QSFP + to 10G SFP + cabling:

For connection between 40G port and 10G port on switch, 40G MTP/MPO breakout cable is suggested, as it features 1 MTP connector at one end and 4 LC duplex connectors at the other end. You can connect 40G transceiver module with MTP/MPO connector like 40GBase-SR4, 40Gbase-CSR4, 40GBASE-PLR4 and 40GBASE-PLRL4 with 40G MTP/MPO breakout cable to achieve 40G QSFP + to 10G SFP + cabling.

Q: 40G QSFP+ Vs. DAC Vs. AOC: How to choose?

 a.Transmission distance≦10m

40G QSFP+ DAC cable is your option. Active and passive 40G DAC can achieve lengths of 10m and 7m respectively. It offers a very cost-effective way to establish a 40-gigabit link between QSFP+ ports or QSFP+ ports and SFP+ ports of switches within racks and across adjacent racks.

 b.Transmission distance:10m~100m

40G QSFP+ AOC provides high cost performance on transmission within short distance. It includes three types, 40G QSFP+ to QSFP+, 40G QSFP+ to 4×SFP+, and 40G QSFP+ to 8×LC. 40G QSFP-8LC AOC cable offers high flexibility for 40G-10G connectivity.

 c.Transmission distance≧100m

40G QSFP+ transceiver module is a preferable choice, which has higher flexibility and adaptability. That makes it easier to deploy 40G QSFP+ to 40G QSFP+ cabling and 40G QSFP + to 10G SFP + cabling.

If you want to know more about 40G cabling options, you can read 40G cabling solutions for data centers.

40G CFP Module Overview And Types

CFP, short for form-factor pluggable, is a multi-source agreement to produce a common form-factor for the transmission of high-speed digital signals. The CFP MSA defines form factors to enable both 40Gb/s and 100Gb/s applications. There are mainly three types of 40G CFP modules, 40GBASE-SR4 CFP for 150m on OM4 MMF, 40GBASE-LR4 CFP for 10km on SMF and 40GBASE-FR CFP for 2km on SMF. Normally, the CFP price is higher than QSFP+. Anyway, CFP modules provide Ethernet users another option for 40 Gigabit Ethernet connectivity.

Should I Choose 40G QSFP+ or CFP Module?

A CFP module is quite large in size, which would not support stacking or ganging. And it does not allow high levels of port side density improvements. The 40G CFP modules could only support CFP ports on 40G switch. 40G QSFP+ modules have higher port flexibility and smaller form factor than 40G CFP modules. Some of them can achieve 4 x 10G connectivity, which is aforementioned. CFP module has not been broadly adopted in data centers, and IT managers have difficulty justifying upgrading their existing 10 GE solutions to these new 40GE modules. 40G QSFP+ modules, however, having been widely applied in data center, enterprise, and service provider networks.

FS.COM 40G QSFP+ And CFP Solution

With the ubiquitous third-party manufacturers for 40G transceiver module, choosing a reliable third-party vendor is of significance. FS.COM is dedicated to provide the best solutions for fiber optical transceivers. For 40G QSFP+ and CFP solution, we offer a wide range of 40G QSFP+ and CFP transceiver modules, DAC and AOC cables, which are compatible to switches of major brands. For AOCs and DACs, we can supply them with different brands of connectors at both ends. Our products have special advantages on price, compatibility, warranty and customizing service.

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