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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
Copper Cabling Choices for 10G Ethernet

Copper Cabling Choices for 10G Ethernet

Nowadays, though fiber becomes popular with the benefit of delivering the lowest latency, many IT departments still use copper cabling for switch-to-switch or switch-to-server connections in 10G Ethernet (10 GbE). Currently, there are two major copper cabling technologies applied for 10 GbE over copper. What are they?

As the following table shown, one of the 10GbE copper cabling options is the SFP+ Direct Attach Copper Cable (DAC Cable), and the other one is the 10GBASE-T with twisted-pair Ethernet cable. In the following section, they are respectively introduced in details.

Media Copper Cable Distance (max) Averange Latency Standard
SFP+ DAC Twin-ax copper SFP+ Cu 10 m (33 ft) 0.1 μs MSA SFF-8431
10GBASE-T Twin-pair Category 6 RJ45 30 m (98 ft)-50 m(164 ft) >1.5 μs IEEE 802.3an-2006
Twin-pair Category 6A RJ45 100 m (328 ft) >1 μs
Twin-pair Category 1 GG45 100 m (328 ft) >1 μs


SFP+ DAC Is Convenient for Short Runs

SFP+ is the form factor for 10GbE optical transceivers. 10G SFP+ DAC cable is designed with SFP+ connectors on two ends of a twin-ax copper cable. Because of its low latency, small form factor, and reasonable cost, it has become the preferred and convenient 10GbE copper cabling option for servers and storage devices in a rack, usually within 10 meters (33 ft). 10G SFP+ DAC can help simplify rack cabling and termination. For instance, in a ToR (Top of Rack) architecture, each server and network storage device can be directly connected to the ToR switch without the need for intermediate patch panels. More over, 10G SFP+ DAC is flexible enough for vertical cabling management within the rack architecture. The only cabling outside the rack is the ToR switch uplink connection to the aggregation layer, making moving racks easy.

10G Ethernet copper cabling option: 10G SFP+ DAC

10GBASE-T With CAT 6A Cable Is Perfect for Long-Term Plan

10GBASE-T was released by IEEE 802.3an in 2006 which specifies 10Gbps data transmission over four-pair copper cabling. 10 GbE over CAT 6A cable and CAT 7 cable that use RJ45 connectors can reach up to 100 meters. Among them, CAT 6A is currently the preferred cable option for future-proofing cabling installations and widely used in 10GbE copper cabling. In addition, when using CAT 6A in 10 GbE systems, choosing the right cable type, namely unshielded or shielded (e.g. UTP or F/UTP) is also necessary. In general applications, the UTP cabling is commonly used. But for long-term consideration and noisy environment, the F/UTP may be better.

10G Ethernet copper cabling option: 10GBASE-T CAT 6A


10G Ethernet over copper still plays an important role in the data center switch/server interconnection. Current copper cabling choices for 10G Ethernet include SFP+ DAC and 10GBASE-T with Ethernet cables. Each of them has its own advantage. The SFP+ DAC is convenient for short runs while the 10GBASE-T solution is perfect for long-term plan in a longer distance. Only the right one is the best. So, how do you plan your copper cabling for 10 GbE?

QSFP+ Transceiver, DAC, AOC – Which Is More Cost-Effective?

QSFP+ Transceiver, DAC, AOC – Which Is More Cost-Effective?

For 40GbE direct cabling between two devices using QSFP+ port, there are several options including QSFP+ transceiver option, QSFP+ DAC (Direct Attach Copper) cable, and QSFP+ AOC (Active Optical Cable). Among these options, each of them has its own merits. Today, I’d like to make a comparison between them from the perspective of the costs.

Case 1: Distances Below 5 m

If the transmission distances is under 5 m, like the case that two switch ports are connected within the same rack or between racks located within the same room. The QSFP+ passive DAC cable is recommended. Take the Cisco compatible QSFP+ optics (Fiberstore Brand) for example:

DAC 5m Cisco QSFP-H40G-CU5M Compatible 40G QSFP+ Passive Direct Attach Copper Cable US$ 65.00
AOC 5m Cisco QSFP-H40G-AOC5M Compatible 40G QSFP+ Active Optical Cable US$ 140.00
Transceiver & Cable Cisco QSFP-40G-SR4 Compatible 40GBASE-SR4 QSFP+ 850nm 150m DOM Transceiver US$ 85.00
5M OM4 12-fiber MTP Fiber Optic Trunk Cable for 40GBASE-SR4 US$ 73.00
Case 2: Distances Below 100 m (< 5 m)

For the case that transmission distance is below 100 m but beyond 5 m, the QSFP+ AOC is an ideal choice for use, namely DAC VS AOC, the AOC win. In this case, the QSFP+ passive DAC cable cannot achieve such long reach requirement because of its performance limitation. While the 40GBASE-SR4 QSFP+ transceiver can do this but the cost of the MTP trunk cable is higher. Thus, here, the compatible QSFP+ AOC is preferred.

AOC 100m Cisco QSFP-H40G-AOC100M Compatible 40G QSFP+ Active Optical Cable US$ 250.00
Transceiver & Cable Cisco QSFP-40G-SR4 Compatible 40GBASE-SR4 QSFP+ 850nm 150m DOM Transceiver US$ 85.00
OM4 12-fiber MTP Fiber Optic Trunk Cable for 40GBASE-SR4 over US$ 500.00
Case 3: Distances Above 100 m

If the transmission distance is longer than 100 m, DAC cables and AOCs are usually not recommended. In this case, the 40G QSFP+ modules which are used for short-reach applications are recommended.

Cisco QSFP-40G-SR4 Compatible 40GBASE-SR4 QSFP+ 850nm 150m DOM Transceiver US$ 85.00
Cisco QSFP-40G-SR4-S Compatible 40GBASE-SR4 QSFP+ 850nm 150m DOM Transceiver US$ 85.00
Cisco QSFP-40G-CSR4 Compatible 40GBASE-CSR4 QSFP+ 850nm 400m DOM Transceiver US$ 110.00

In addition to the QSFP+ modules, you may need to select the right cables and patch panels according to your requirements. These costs should be considered in your plan. The detailed prices will not list here.

Of course, all above are rough estimates of the optics. In practical application, more details are included. Users can consult clearly when purchasing. In addition, for short-distance migration to 40 GbE, the breakout DAC cable and AOC could be another good choices. Meanwhile, it should be note that the prices listed above are the product list prices of Fiberstore Website. If you wanna buy, please to real-time prices shall prevail in

Comparison of 40GbE Connectivity Options

Comparison of 40GbE Connectivity Options

High speed and wide bandwidth demands drive data centers to consolidate into more complex systems. The speed of data center now is increasing to 40 Gbps and eventually to 100 Gbps. Thus, new optical technologies and cabling infrastructure are required. In this post, I will introduce some commonly used fiber optic cabling connectivity options for 40Gbps infrastructure.

Pluggable Optical Modules: 40G QSFP+ Transceivers
As we know, fiber optic transceiver is an electronic device that receives an electrical signal, converts it into a light signal, and launches the signal into a fiber. It also receives the light signal, from another transceiver, and converts it into an electrical signal. It is the key component in fiber optic transmission. The basic interface of 40G pluggable optical modules are 40GBASE-LR4 and 40GBASE-SR4 in QSFP+ form factor, such as Cisco QSFP-40G-LR4 and QSFP-40G-SR4.


40GBASE-LR4 QSFP+: 40GBASE-LR4 transceiver support with a link length up to 10 kilometers over 1310 nm single mode fiber, LC Connector. It is most commonly deployed between data-center or IXP sites with single mode fiber.

40GBASE-SR4 QSFP+: 40GBASE-SR4 transceivers are used in data centers to interconnect two Ethernet switches with 8 fiber parallel multimode fiber OM3/OM4 cables. It can support the transmission distance up to 100 m with OM3 fiber and 150 m with OM4 fiber. The optical interface of 40GBASE-SR4 QSFP+ is MPO/MTP.

In addition, for single-mode fiber transmission, there are 40GBASE-LR4 Parallel Single Mode (PSM) transceivers which are used to provide support for up to four 10Gbps Ethernet connections on a QSFP+ port over single mode fiber at distances up to 10 km. For multimode fiber transmission, QSFP+ extended SR4 transceivers are developed which is designed with optimized VCSEL with better performance of RMS spectral width compared with QSFP+ SR4. QSFP+ extended SR4 transceivers can support transmission distance up to 300 m with OM3 fiber and 400 m with OM4.

Passive & Active Direct Attach Copper Cables
The QSFP+ passive or active direct attach copper cables are designed with twinax copper cable and terminated with QSFP+ connectors. The main difference between passive QSFP+ DAC and active QSFP+ DAC is that the passive one is without the active component. They provide short distance (same shelf) inexpensive connectivity at up to 40Gbps rates and operate 4 independent 10G channels using the QSFP connector footprint. Each of the four channels can operate at multi-rate speeds Gigabit to 10Gbps.


Active Optical Cable (AOC) Assemblies
Active optical cable, namely AOC brings a more flexible cabling than direct attach copper cables with the advantages of lighter weigth, longer transmission distance and higher performance for anti-EMI. Now, 40G AOC assemblies are popular with users.


After introducing the basic options of 40G cabling connectivity, we take a conclusion for the above content in the following tables:



In addition, don’t forget there are some typical cabling components you will require when building 40G cabling, such as MTP trunk cables, MTP cassettes, LC to MTP jumpers and so on.

MTP Assemblies

Fiberstore offers a comprehensive solution for 40G fiber optic cabling connectivity. What’s more, products such as 40GBASE-LR4 and 40GBASE-SR4 QSFP+ modules are in stock and can shipped in 12hrs. For more information, please visit