Browsed by
Tag: 40G QSFP+ transceiver

40G QSFP+ Breakout Cables vs. QSA Module

40G QSFP+ Breakout Cables vs. QSA Module

When one end of the network is running on a 40 Gigabit platform, and the other end of the network is running at lower speeds such as 10 Gbps, migration is required. Using fan-out technology and QSA are two different methods to achieve the migration between 40 Gigabit Ethernet and 10 Gigabit Ethernet. But which is better?

Expands the 40G Data Pipe into 4x10G Lanes With Breakout Cables

40G QSFP+ to 4×10 SFP+ breakout cables including direct attach copper cable (DAC) and active optical cable (AOC) can take a 40 Gigabit physical interface and break it out into four SFP+ interfaces, converting the downlink 40G port of ToR (Top of Rack) access layer switch into 4x10G channels then connect to the cabinet server port. Thus, they are considered as the most cost-effective solution for 10G to 40G migration in short-reach interconnect environment.


Converting a QSFP+ Port to an SFP+ Port With QSA

QSA (Quad Small Form-Factor Pluggable Adapter) is the first solution for the QSFP+ to SFP+ conversion challenge in the world. It enables smooth connectivity between devices that use quad lane ports and 10 Gigabit Ethernet hardware that uses SFP+ based cabling. In other words, with QSA, you can effectively use a QSFP or QSFP+ module to connect to a lower-end switch or server that uses an SFP+ based module.

QSA module is built in a QSFP+ form factor with a cage for SFP+ module at the back. When inserting an SFP+ into a QSA connected to a 40 Gigabit port, QSA acts as an interface for the SFP+. This interface enables you to directly plug in an SFP+ originating at a 10 Gigabit Ethernet port on a switch or server.


40G QSFP+ to 4×10 SFP+ Breakout Cables vs. QSA

As mentioned above, we can use QSFP+ to 4x10G SFP+ breakout cables to split a 40 Gigabit port on a switch or a server into four 10 Gigabit ports. Or use QSA to convert a QSFP+ port to an SFP+ port. However, which one is better for an optimal ROI (Return on Investment)? Obviously, the former is more cost-effective for these reasons:

  • Technology and products of QSFP+ to 4x10G SFP+ breakout cables are more mature in today’s market. Users can even use the 3rd party product without considering the problem caused by vendor lock-in.
  • QSFP+ to 4x10G SFP+ breakout cables split the 40G channel into 4x10G channel which provides four times more data transfers compared to a QSA that just provides connectivity only for a single 10G connection.
  • QSFP+ to 4x10G SFP+ breakout cables support both DAC and optical connectivity, and are cheaper than the expensive QSA.

40G QSFP+ to 4×10 SFP+ breakout cables and QSA modules can both be used for migration between 40G and 10G ports. But considering cost, performance, and compatibility actual environment, the 40G QSFP+ to 4×10 SFP+ breakout cables seem to be better. FS.COM offers a wide range of 40G QSFP+ to 4×10 SFP+ breakout cables including QSFP+ to 4×10 SFP+ DACs and QSFP+ to 4×10 SFP+ AOCs, which are 100% compatible for various platform, like Cisco, HPE, Juniper, and so on. For more information, please visit or contact

Buyer Guide: FS.COM offers cost-effective and highly compatible QSFP BiDi transceivers which are tested to ensure 100% Cisco compatibility.
Categories Description
40G QSFP+ to 4xSFP+ DAC Every cable is individually tested on corresponding equipment such as Cisco, Arista, Juniper, Dell, Brocade and other brands, passed the monitoring of Fiberstore’s intelligent quality control system
40G QSFP+ to 4xSFP+ AOC
How to Choose 40G QSFP+ Modules for Multimode Applications?

How to Choose 40G QSFP+ Modules for Multimode Applications?

cisco nexus 9396px switch with QSFP-40G-SR4

With the popularity of 40G QSFP+ modules in datacom industry, there are more alternatives for choose to replace the traditional 40GBASE-SR4 QSFP+ modules for multimode applications. To choose the most proper 40G QSFP+ modules for your applications not only offers the high performance but also saves more cost in the project.

Types of 40G Multimode QSFP+ Modules

Currently, there are three kinds of multimode 40G QSFP+ modules available in the market. They are:

Type Wavelength Distance Connector Type
40GBASE-SR4 QSFP+ 850 nm 150 m (OM4)
100 m (OM3)
40GBASE-CSR4 QSFP+ 850 nm 400 m (OM4)
300 m (OM3)
40GBASE-SR Bi-Directional QSFP+ 832 nm – 918 nm, BiDi 150 m (OM4)100 m (OM3)30 m (OM2) LC

So, which one is the best for you? In the following sections, several factors should be considered.

Distance Consideration

The maximum transfer distance of QSFP+ modules refers to how long distance can the module support to transmit. It usually depends on the transmission distance that your project is required. In general, 40GBASE-SR4 QSFP+ module can support up to 100 meters over OM3 multimode fiber and 150 meters over OM4 multimode fiber. In other word, if your expected transmission distance is under 150 meters, you can choose 40GBASE-SR4 QSFP+ module with OM4 fiber cable. If you have a longer distance requirement, the 40GBASE-CSR4 will be better for you since it can support up to 400 meters over OM4 multimode fiber.

Cabling Consideration

Generally, current multi-mode optics standards for 40GbE use parallel technology, namely using multiple 10Gbps lasers, simultaneously transmitting across multiple fiber strands to achieve high data rates (4 x 10 Gbps). Because of this, 40G optics use MPO or MTP cabling instead of the traditional duplex LC cabling. The most commonly used MPO/MTP cable presents 12 separate strands of multi-mode fiber in a single ribbon cable. 40G multimode QSFP+ modules with MPO/MTP interface include 40GBASE-SR4 and 40GBASE-CSR4. However, if you deploy the 40 GbE over the existing 10GbE infrastructure, the former two kinds of 40G modules are not applicable. In this case, you may choose the 40G BiDi QSFP+ module which can support up to 150 meters over OM4 multimode duplex LC cabling.

Other Considerations

In addition to distance and cabling considerations, other considerations such as compatibility, receiver sensibility, temperature and so on are also important. Users should have a proper plan of the network and choose the proper parameters depending on the requirements.

Compatibility Test of FS.COM 40GBASE-SR4 QSFP+ Transceiver on Cisco Nexus 9396PX Switch


40G QSFP+ modules are key components for 40GbE deployment. To choose the proper and cheap 40G QSFP+ can benefit the whole project. I will recommend you to visit FS.COM. They have a wide range options of 40G QSFP+ modules with very affordable prices. They may be an ideal choice for you.

Optics Use Cases for 40 Gigabit Ethernet Connectivity

Optics Use Cases for 40 Gigabit Ethernet Connectivity

The 40 Gigabit Ethernet (GbE), used in today’s networks as the preferred spine uplink technology, has become commonplace in data centers. With the rise of 40GbE QSFP+ optics market, various of optics solutions are available, which offer users a lot of flexibility in connectivity. Today, I am going to summarize some 40 Gigabit fiber optic connection use cases of several types of commonly used 40GbE QSFP+ optics.

Case One: QSFP+ to QSFP+ Direct Connectivity

For 40GbE to 40GbE connectivity, namely the interconnection between two QSFP+ ports, users can use different optics and cables options according to different transmission distances.

40GbE direct connectivity

  • For distances of up to 7 meters: QSFP+ to QSFP+ DAC (Direct Attach Copper) cables
  • For distances of up to 100 meters: QSFP+ to QSFP+ AOC (Active Optical Cable) or 40GBASE-SR4 QSFP+ transceiver with OM3 multimode fiber with MTP/MPO connectors or OM4 multimode fiber with MTP/MPO connectors (up to 150 meters)
  • For distances of up to 300 meters: 40GBASE-CSR4 QSFP+ transceiver with OM3 multimode fiber with MTP/MPO connectors or OM4 multimode fiber with MTP/MPO connectors (or up to 400 meters)
  • For distances of up to 1 kilometers: 40GBASE-PLRL4 QSFP+ transceiver can be used with single-mode fiber with MTP/MPO connectors
  • For distances of up to 10 kilometers: 40GBASE-LR4 QSFP+ transceiver can be used with single-mode fiber with LC connectors

Tips: The standard QSFP+ MTP/MPO connector is 12-fiber connector, but use 8 out of 12 fibers.

Case Two: 40GbE to 10GbE Ports Breakout

As we know, 40GbE ports can be used either as a single port or turned into four 10GbE ports. Thus, you can use so-called QSFP+ breakout or fan-out cables with QSFP+ on one side and four SFP+ on the other side to increase the number of available 10GbE ports.

In general, according to different distance requirements, the basic three types of solutions are available:

40GbE breakout connectivity

  • For distance of up to 5 meters: QSFP+ to SFP+ DAC Breakout Cables
  • For distance of up to 100 meters: QSFP+ Breakout AOCs
  • For distance of up to 300 meters: MTP/MPO to 4xLC Duplex OM3/OM4 multimode fiber breakout cables (mpo to lc duplex breakout cable) with the 40GBASE-CSR4 transceiver

Tips: When connect to networking switches or to server adapters which support SFP+ fiber optic connectivity, the QSFP+ DAC breakout cables are always the preferred option.

Case Three: Deploy 40GbE With Existing 10GbE Cabling Using LC Connectors

In today’s server networks, 10GbE has become commonplace. 10GbE multimode cabling with LC duplex connectors is the main infrastructure of 10GbE network. To leverage existing 10GbE cabling using LC connectors, the 40GBASE-SR QSFP+ Bi-Directional (BiDi) transceiver is an ideal choice for you. Used with WDM (Wavelength Division Multiplexing) technology, the 40GBASE-SR QSFP+ BiDi transceiver can support up to 100 meters with OM3 multimode fiber and up to 150 meters with OM4 multimode fiber cables with LC duplex connectors, allowing reuse of existing 10-Gbps fiber infrastructure for 40-Gbps connections so that helps reduce overall costs and installation time.

40GbE bidi


According to the above contents, we learned that the optics market for 40GbE connectivity is now relatively mature. Users can choose the most proper solution according to their network plan, requirements, and budget.

Use 40G BiDi QSFP+ to Transmit Over DLC MMF Cabling

Use 40G BiDi QSFP+ to Transmit Over DLC MMF Cabling

40G BiDi QSFP+As we know, the most commonly used solution for 40GbE multimode application is based on the interface standard QSFP-40G-SR4, which is running over multimode fiber (MMF) pre-terminated with 8-fiber MPO/MTP connectors. This causes a problem of fiber waste of the existing 10GbE infrastructure. So, how to reuse the exsiting 10GbE LC MMF cabling to achieve 40GbE network? The 40G BiDi QSFP+ transceiver may be an ideal choice for this requirement.

Today’s data centers are architected around 10 GbE, primarily focusing on 10GBASE-SR using duplex MMF with LC connectors. Data center operators want to upgrade from 10G to 40/100G without touching the duplex MMF infrastructure. This is becoming one of the data center interconnect trends. In order to meet this demand, the 40GbE BiDi QSFP+ transceiver has launched to the market. It offers users an option to run 40 GbE over duplex MMF with LC connector.

How can 40GbE BiDi QSFP+ transceiver do this? Now, turn to its working principle. As we know, 40GBASE-SR4 QSFP+ optics use independent lanes for transmit and receive (4 x Tx and 4 x Rx). The data rate of each lane is 10 Gbps. Thus, 8-fiber strands (8-fiber MPO/MTP) are required for using this optics. But for 40GbE BiDi QSFP+, as shown in the picture below, only two lanes are required, for each of 20Gbps. Each transmitted and received simultaneously on two wavelengths over a single MMF, enabling an aggregated 40Gbps link over a two-strand multimode fiber connection.

40GBASE SR4 QSFP+40GBASE-SR4 QSFP+ Working Principle

40GbE BiDi QSFP+40GbE BiDi QSFP+ Working Principle

Obviously, 40GbE BiDi QSFP+ transceiver has the absolute superiority on using the duplex MMF. However, some users may care the cost since that the cost of a 40GbE BiDi QSFP+ transceiver is much expensive than a 40GBASE-SR4 QSFP+ optics. But on the whole cost, you may find that the 40GbE BiDi QSFP+ is more cost-effective. Because you can save more on the fiber cost since the cost of fiber optic cables is also a big spending in your whole project.

Optics Channel Data Rate per Channel Fiber Type Price
40GBASE-SR4 QSFP+ 4 10 Gbps 8-fiber MPO/MTP MMF US$ 65.00
40GbE BiDi QSFP+ 2 20 Gbps Duplex LC MMF US$ 300.00

If you are still finding a way that can offer maximum reutilization of existing 10GbE fiber plant on 40/100G, help you achieve the 40GbE migration in a more cost-effective manner, the 40GbE BiDi QSFP+ transceiver may be your preferred choice. And in FS.COM, you can always find the high-performance transceivers in the most competitive price.


QSFP+ AOC – A Favored Solution for 40G Network

QSFP+ AOC – A Favored Solution for 40G Network

As the need for increased network bandwidth to meet the global IP traffic demand is growing rapidly, more and more data centers are deploying 40G Ethernet links. And there are various technologies and solutions to be selected for 40G transmission. 40G QSFP+ transceivers, 40G direct attach cables (DACs) and active optical cables (40GbE QSFP+ AOC Cable) are three kinds of fiber optics used to achieve 40G interconnections in data center. Among them, 40G AOCs are very popular and have a broad prospect. In fact, AOCs are widely used in many fields and play an important role in promoting the traditional data center to step into optical interconnection.

What’s AOC?

AOC is a kind of optical transceiver assemblies that is terminated with transceiver-style plugs to be used in the same ports where optical transceivers are used. And 40G AOC is a 4-channel parallel active optical cable, each channel is capable of transmitting data at dates of about 10Gb/s per direction, providing an aggregated rate of about 40Gb/s over multi-mode fiber (MMF) ribbon cables. Unlike DACs, AOCs are active devices, which incorporate active electrical and optical components to boost/receive signal via optical fiber. And they are embodied the latest technology capable of providing the highest data rates.


Why AOC Is Favored in 40G Network?

As an alternative to optical transceivers, 40G AOCs use electrical-to-optical conversion on the cable ends to improve speed and distance performance of the cable without sacrificing compatibility with standard electrical interfaces. Nowadays, active optical cabling is one of the fastest growing technologies in the data center space. QSFP+ AOCs are popular in 40G network for the following reasons.

Less Expensive

Compared with 40G QSFP+ transceivers, 40G AOCs are much more cost-effective solutions for the data center. Firstly, the QSFP+ transceivers terminated to the cable are cheaper than the 40G QSFP+ transceivers for the reason that there are no lasers in the terminated transceivers (the lasers in the transceivers are very expensive). In addition, the AOC eliminates the separable interface between transceiver module and fiber cable. That’s to say, the transceivers are permanently attached to the fiber cables and no patch cables are needed. While the 40G QSFP+ transceivers need to be used together with fiber patch cords which may be expensive (as the following figure shows). Furthermore, since there are no air holes between the transceivers and cables, AOCs can provide protection from environmental pollutants and other user trouble during installation.

QSFP+ AOC link vs 40G transceiver link
Lighter and With Higher Performance

AOCs are originally invented to replace copper technology and to facilitate high-speed data connectivity for storage, networking, and high-performance computing (HPC) applications. It is known to us that DACs are heavy, bulky and require significantly higher power, making it difficult to physically manage the data center. And the nature of electrical signals, electromagnetic interference (EMI) also limits DACs’ performance and reliability. AOCs, however, provide lighter weight, a smaller size, EMI immunity, a lower interconnection loss, and reduced power requirements.

More Customer-Friendly

Consisting of a complete fiber-optic data link (transceivers plus cable) that can be plugged into existing ports, AOCs enable a very rapid introduction of optical connections. AOCs provide customers with access to all the great advantages of fiber (for example, high bandwidth, relatively thin, lightweight cable and so on) in a plug-in format. Furthermore, used in a largely electrical data communications infrastructure, AOCs enable the end users to literally plug into the power and security of a fiber-optics link without any special knowledge of fiber optics.


As people expect more information to be available at their fingertips, our communications systems will need to be quicker—and active optical cable is one of the best solutions to this challenge. Fiberstore provides a wide range of solutions for 40G network, including the above mentioned 40G QSFP+ transceivers, 40G QSFP+ DACs and 40G QSFP+ AOCs. We highly recommend 40G QSFP+ AOCs to be used in data center interconnections. All of our optical assemblies are tested in original-brand switch which ensures the 100% compatibility to your device. For more information or quotation, please contact us via