Tag Archives: QSFP+

What Is QSFP Connector, QSFP+ Connector and QSFP28 Connector?

Nowadays, fibre optic technology shows its unsurpassable advantage in telecommunication. Hence, optical transceiver modules are widely used in data centre and other situations. When it comes to various types of data rate and interface of optical transceivers, there are lots of abbreviations to clarify. This article focuses on the introduction of QSFP connector, QSFP+ connector and QSFP28 connector. They share the same small form factor, but differ in supporting data rate and breakout connection.

QSFP Connector

QSFP is the abbreviation of Quad (4 channel) Small Form Factor Pluggable. Supporting Fibre Channel, Infiniband, Ethernet, Sonet/SDH and other proprietary interconnects, QSFP connector is a hot-pluggable, compact transceiver available for use in singlemode and multimode applications. QSFP transceiver can also support 4 independent channels which can transmit individually at the data rate up to 1.25Gbp/s and the aggregate speed of the 4 channels up to 4.3Gbp/s. For using 4x1G lanes, QSFP connector was only found in some FC/IB contexts.

QSFP+ Connector

Short for Quad Small Form Factor Pluggable Plus, QSFP+ connector is regarded as the enhanced generation of QSFP connector. Why do we call QSFP+ the plus one? Because it can support Infiniband, Fibre Channel and Ethernet at 10Gbp/s per channel, thus the combined data rate of the 4 channels can reach 40Gbp/s, which is a distinct improvement in data transmission speed. Besides, like QSFP connector, 40G QSFP+ interface can support transmission and network link over both singlemode and multimode infrastructures. To enable 40G QSFP+ connector to be splitted into 4 independent data streams for different network equipment, AOC breakout cable, DAC breakout cable and other types of breakout cables are used. Besides, the main types of QSFP+ connector include QSFP+ SR4, QSFP+ PLRL4, QSFP+ LR4 and OTU3, QSFP+ CSR4, QSFP+ UNIV, QSFP+ LR4L, QSFP+ SR Bi-Directional, QSFP+ PLR4, QSFP+ER4 and OTU3.

qsfp connector

QSFP28 Connector

With the same quad based interface as QSFP and QSFP+ connector, QSFP28 fibre optic transceiver can transmit optical signals at 100Gbp/s. Each channel of QSFP28 connector can transmit individually at the data rate up to 28Gbp/s. Outstripping CFP, CFP2 and CFP4 connectors, QSFP28 connector has become the preferred solution of 100G network upgrade for its high flexibility and smaller form type. The flexibility of QSFP28 allows it to be used in several kinds of combination, including 100Gbp/s, 2x50Gbp/s and 4x25Gbp/s. Like QSFP+ connector, depending on the application, there are different options of breakout cable to consider, such as AOC breakout cable, DAC breakout cable and other types of breakout cables. Besides, there is an important note, that a QSFP28 connector can’t be broken down into 10Gbp/s channels. However, QSFP28 is backward compatible, so when it is used in a QSFP+ port , it would allow a breakdown into 4x10Gbp/s SFP+ channels. Lastly, there are several types of QSFP28 connector: QSFP28 SR4, QSFP28 PSM4, QSFP28 CWDM4 and QSFP28 LR4.



QSFP, QSFP+ and QSFP28 connectors are introduced in this article from the aspects of form factor, supporting data rate, breakout connection and types. With the above information, it would be easier for you to choose QSFP, QSFP+ and QSFP28 connectors. QSFP connectors are often used in 4x1G lane. While QSFP+ connectors are mostly used in 40G lane, and QSFP28 connectors are mainly used in 100G lane. Besides, QSFP+ and QSFP28 can be splitted into several streams by using breakout cables. ALL in all, your choice need to depend on your network situation and requirement. If you need a little more help and advice with any of QSFP optics or fibre connectivity cables, then please do not hesitate to let us know. For purchasing high quality QSFP, QSFP+, QSFP28 connectors and QSFP cables with low cost or for more products’ information, please contact us at sales@fs.com.

Difference Between QSFP, QSFP+, QSFP28

SFP is short for small form factor. It refers to fibre optic transceivers supporting 1Gbps data rate. Except SFP, current market is full of various types of fibre optic transceivers, such as QSFP, QSFP+ and QSFP28. At the first sight, these transceiver modules are very similar. But actually, they have big differences. To know the difference clearly is good to make the right choice for your network connection. So what are the differences between QSFP,  QSFP+, QSFP28?


“Q” of QSFP means quad (4 channels). QSFP is a compact, hot-pluggable transceiver used for data communications. The QSFP specification supports Ethernet, Fibre Channel, InfiniBand and SONET/SDH standards with different data rate options. QSFP transceivers support the network link over singlemode or multimode fibre patch lead. QSFP modules are commonly available in several different types: 4x1G QSFP, 4x10G QSFP+, 4x28G QSFP28. From this side, QSFP vs QSFP+ vs QSFP28 all share the same small form-factor. literally QSFP uses 4x1G lanes and was only found in some FC/IB contexts.

While QSFP+ transceivers, evolving from 4x1G lanes (QSFP) to 4x10G lanes, are designed to support 40G Ethernet, Serial Attached SCSI, QDR (40G) and FDR (56G) Infiniband, and other communications standards. QSFP+ standard is the SFF-8436 document which specifies a transceiver mechanical form factor with latching mechanism, host-board electrical-edge connector and cage. QSFP+ modules integrates 4 transmit and 4 receive channels plus sideband signals. Then QSFP+ modules can break out into 4x10G lanes. QSFP+ modules are used to connect switches, routers, Host Bus Adapters (HBAs), enterprise data centres, high-performance computing (HPC) and storage. But some may think QSFP as the same with QSFP+, especially in the Ethernet world.


QSFP+ and QSFP28 differs in “28” as the name says. QSFP28 is a hot-pluggable transceiver module designed for 100G data rate. QSFP28 integrates 4 transmit and 4 receiver channels. “28” means each lane carries up to 28G data rate. QSFP28 can do 4x25G breakout connection, 2x50G breakout, or 1x100G depending on the transceiver used. While QSFP+ supports the data rate of 40G, 4 channels for transmitting and 4 channels for receiving, each lane carrying 10G. QSFP+ can break out into 4x10G or 1x40G connection.

qsfp28 vs qsfp+

Usually QSFP28 modules can’t break out into 10G links. But it’s another case to insert a QSFP28 module into a QSFP+ port if switches support. At this situation, a QSFP28 can break out into 4x10G like a QSFP+ transceiver module. One thing to note is that you can’t put a QSFP+ transceiver into a QSFP28 port to avoid destroying your optics.


Compatible with major brands such as Cisco, Juniper, Arista, Brocade, etc., FS.COM QSFP+ and QSFP28 modules can support both short and long-haul transmission. Here lists our generic QSFP+ and QSFP28 modules in the following table.

FS.COM Generic QSFP+
Model Description Price List In Stock
17931 40GBASE-SR4 QSFP+ 850nm 150m MPO Transceiver for MMF US$ 49.00 1061 pcs
34917 40GBASE-PLRL4 QSFP+ 1310nm 2km MPO Transceiver for SMF US$ 220.00 49 pcs
24422 40GBASE-LR4 and OTU3 QSFP+ 1310nm 10km LC Transceiver for SMF US$  340.00 50 pcs
34912 40GBASE-CSR4 QSFP+ 850nm 400m MPO Transceiver for MMF US$  70.00 141 pcs
35205 40GBASE-UNIV QSFP+ 1310nm 2km LC Transceiver for SMF&MMF US$  340.00 18 pcs
34913 40GBASE-LR4L QSFP+ 1310nm 2km LC Transceiver for SMF US$ 340.00 44 pcs
48721 40GBASE-SR Bi-Directional QSFP Module for Duplex MMF US$  300.00 106 pcs
35209 40GBASE-PLR4 QSFP+ 1310nm 10km MPO Transceiver for SMF US$  380.00 34 pcs
35211 40GBASE-ER4 and OTU3 QSFP+ 1310nm 40km LC Transceiver for SMF US$  1,500.00 40 pcs
39986 40GBASE-LR4 CFP 1310nm 10km SC Transceiver for SMF US$  800.00 Available
FS.COM Generic QSFP28
Model Description Price List In Stock
35182 Generic Compatible QSFP28 100GBASE-SR4 850nm 100m Transceiver US$ 270.00 38 pcs in stock
65216 Generic Compatible QSFP28 100GBASE-PSM4 1310nm 500m Transceiver US$ 750.00 26 pcs in stock
65214 Generic Compatible QSFP28 100GBASE-CWDM4 Lite 1310nm 2km Transceiver US$ 1,350.00 26 pcs in stock
65215 Generic Compatible QSFP28 100GBASE-CWDM4 1310nm 2km Transceiver US$ 1,350.00 26 pcs in stock
39025 Generic Compatible QSFP28 100GBASE-LR4 1310nm 10km Transceiver US$ 2,800.00 Available

The difference between QSFP vs QSFP+ vs QSFP28 has been stated clearly in this article. Though QSFP is thought as QSFP+, when talking about 40G, actually we mean QSFP+. QSFP+ vs QSFP28 mainly differs in data rate and breakout connection. So you must be sure what you need is 40G QSFP+ or 100G QSFP28 for high density applications, especially when connecting with 10G SFP+.

Related Article:  How to Match Fibre Patch Cable for Your Multimode SFP?

Decoding 100G QSFP28 Transceiver

Cost-effective QSFP-40G-LX4 Transceiver

10Gbps data rate can’t meet the high-speed needs. So people start to develop 40Gbps solutions. As a result, a variety of 40G QSFP+ transceivers can be found in the market, like QSFP-40G-SR4, QSFP-40G-CSR4, QSFP-40GE-LR4, QSFP-40G-LX4, etc. Different transceivers offer different ways to migrate from 10G to 40G. Among these solutions, which one is the most cost-effective? The answer is QSFP-40G-LX4. This following test will tell about QSFP-40G-LX4 in details.

QSFP-40G-LX4 Introduction

Juniper networks JNP-QSFP-40G-LX4 transceiver applies the new 40 Gigabit Ethernet technology — LX4 offered by Juniper. This transceiver module uses the same infrastructure as 10 GbE. The LX4 technology can meet all the performance criteria of today’s data centre in which two multimode fibre strands and duplex LC connectors are used for 40GbE connectivity just like existing 10GbE infrastructure.

As the above mentioned, QSFP-40G-LX4 transceiver provides the ability to transmit full-duplex 40Gbps data traffic over one duplex multimode fibre cable with LC connectors. In other words, this transceiver delivers 40 Gbps over duplex OM3 or OM4. It can achieve the direct connection from 10 Gbps to 40 Gbps through LC duplex fibre cable. The QSFP-40G-LX4 has four 10Gbps channels. Each channel can transmit and receive simultaneously on four wavelengths over a multimode strand (see the following figure). Thus, the 40Gbps link can be connected by two multimode strands. QSFP-40G-LX4 connections can support the data transmission distance up to 100 metres over OM3 and 150 metres over OM4.


QSFP+ LX4 Saving Cost

When preparing to migrate from 10G to 40G network, cost is one of the most important thing to be considered. As we know, existing 10Gbps connections commonly use MMF cables with LC connectors. While most 40Gbps connections often need eight fibre strands, each four parallel strands for transmitting and receiving respectively. Take QSFP-40G-SR4 an example, it uses 12-fibre MPO cable. Under that condition, 10Gbps cabling infrastructure should be upgraded to migrate to 40Gbps. It will cause additional cost of new patch cables, new patch panels, and expansion of the current fibre trunk.


However, QSFP LX4 transceiver can solve the cost issue. With QSFP-40G-LX4, it’s much easier to migrate from 10G to 40G network without considering the problem of deploying new cabling infrastructure or buying migration cassettes. Instead, it only needs to replace the 10GbE optical module with 40G-LX4. Because QSFP+ LX4 uses LC connectors. It allows the same cables to be used for direct 10 Gbps connections to direct 40 Gbps connections, resulting in zero-cost cabling migration. No additional spending on cabling will be required if QSFP+ LX4 transceivers are used for all 40 Gbps links. As a result, users realize 100 percent investment protection of their existing infrastructure and incur no additional cabling costs. This is a significant advantage when compared to the cost of reconstructing the cabling system using QSFP SR4 transceivers. If the cabling for this network is an expansion to the existing cabling system, the 40 Gbps connections can be built using MMF cables and QSFP SR4 transceivers or QSFP+ LX4 transceivers. QSFP+ LX4 can save a lot for 40 Gbps migration.


There are many solutions for the migration from 10G to 40G. QSFP+ LX4 technology removes 40 Gbps cabling cost barriers for migrating from 10 to 40 Gbps in data centre networks. QSFP+ LX4 transceivers provide 40 Gbps connectivity with huge cost savings and simplicity for next-generation data centre 40GbE deployments. The QSFP+ LX4 transceiver allows organizations to migrate their existing 10 Gbps infrastructure to 40 Gbps at zero cost of fibre, and to expand the infrastructure with low capital investment. FS.COM provides JNP-QSFP-40G-LX4 transceivers with high quality and 100% compatibility. All of transceivers have gone through test-assured program before reaching customers.

Preparation for 40G/100G Migration

10G is now common in large enterprises. New network trends continue to drive the demand for high-speed Ethernet, such as the virtualization trend, network storage trend, I/O convergence trend, and data centre network aggregation trend. So 40G and 100G as well as corresponding equipment are introduced into the market. The migration from 10G to 40G/100G is inevitable.

IEEE and TIA Standards

Before planning for migration to 40G/100G network, we should better know well about high-speed Ethernet. The following will talk about it from the side of standards. Because structured cabling systems design is always guided first by standards. The standards for 40G and 100G are significantly different from previous generations; active equipment and how information is transmitted are unique.

First, it’s IEEE standards. IEEE creates the standards that define performance parametres. IEEE 802.3ba 40Gb/s and 100Gb/s Ethernet is the only current standard that addresses the physical layer cabling and connector media maximums for 40/100G fibre channel requirements. IEEE 802.3ba-2010 standard was approved at the June 2010 IEEE Standards Board meeting. The standard is shown in the following table.

Fibre Type Max Distance Max Channel

Insertion Loss

Max Channel Connector

 Insertion Loss

10G OM3 300m 2.6 dB 1.5 dB
10G OM4 550m 2.6 dB 1.5 dB
40/100G OM3 100m 1.9 dB 1.5 dB
40/100G OM4 150m 1.5 dB 1.0 dB

Second, it’s TIA (Telecommunications Infrastructure Standard). For data centres, TIA defines how to apply the parametres to structured cabling systems. It establishes design criteria including space and layout, cabling infrastructure, tiered reliability, and environmental considerations. The standard recommends using the highest capacity media available to maximize infrastructure lifespan.

40G/100G Using MPO/MTP Interface

1G and 10G networks use GBIC (Gigabit interface converter). For example, generally the transceiver SFP+ (small form-factor pluggable) is for 10G network. Later the fibre connectivity in high-speed active equipment becomes condensed and simplified. Transceivers for 40G and 100G are QSFP (quad small form-factor pluggable), CFP and CXP (100G form-factor pluggable). MPO/MTP is the designated interface for multimode 40/100G, and it’s backward compatible with legacy 1G/10G applications as well. Its small, high-density form factor is ideal with higher-speed Ethernet equipment.


Figure1. MPO/MTP Connector

40G and 100G Ethernet employ parallel optics. Data is transmitted and received simultaneously on MTP interfaces through 10G simplex transmission over each individual strand of the array cable.

After introducing some basics of the high-speed Ethernet, we’ll discuss the structured cabling system of migration to 40G and 100G networks in the simplest and most-effective way.

12- or 24-Fibre Cabling Infrastructure

The system includes configurations for 10G to 40G/100G networks over 12- or 24-fibre MTP cabling. What’s the difference between the two methods? Which one is better? The sections will compare the two from the sides of migration, density and congestion.

Migration To achieve the migration, components like trunks, harnesses, array cords, modules, and adapter plates are needed. With the 40G 12-fibre legacy configurations, a second trunk and another set of array harnesses will be needed to achieve 100% fibre utilisation (as shown in Figure 2). For 100G, it also needs these additional components with 12-fibre legacy configuration. But with 24-fibre trunks, a single cable can support a 1G-100G channel and simplify network upgrades immensely (as shown in Figure 3). When equipment is upgraded, there is no need to install new trunks. In addition, limiting changes can reduce the inherent risks to network security and integrity.


Figure2. 12-Fibre Cabling


Figure3. 24-Fibre Cabling

Density The higher density connectivity, the more rack space for active equipment. Thus less floor space is needed. In this way, 24-fibre cabling has the obvious advantage. If the active equipment is configured for 24-fibre channel/lane assignments, there will be twice as as many connections with the same number of ports compared to 12-fibre.

Congestion The more connectivity you are able to run in the same footprint, the more crowded it can become at the rack or cabinet. Fewer trunks reduce cable congestion throughout the data centres. Using 24-fibre MTP trunks for the cable runs will save half the number of cables versus 12-fibre in the network. Runs carry a lighter load, fibres are easier to manage, and improved airflow reduces cooling costs. So 24-fibre MTP trunks offer a huge benefit.


The high-speed network will become more and more popular. It’s very important to know something about the migration to 40G/100G. To upgrade your network, 24-fibre MTP will be a better fibre cabling choice compared with 12-fibre. Do you prepare well for the great migration?

Which One Will You Choose for Your 40/100G Network, OM3 or OM4?

40G has been widely used in data centres. 100G will also come soon. To meet these high bandwidths, related fibre cables are needed. OM3 and OM4 can be used to transmit parallel optical signal. But what is their difference? Which one will you choose for your network?

Both OM3 and OM4 are laser optimized fibre. Their cores size is 50/125. Connectors are the same and both operate 850nm VCSELS (Vertical-Cavity Surface-Emitting Lasers) transceivers. So the difference lies in the construction of the fibre cable, which means OM4 cable has better attenuation and can operate at higher bandwidth than OM3.


Attenuation is the reduction in power of the light signal as it is transmitted (dB). Attenuation is caused by losses in light through the passive components, such as cables, cable splices, and connectors. As the connectors are the same, so the difference in OM3 and OM4 performance is in the loss (dB) in the cable. The maximum attenuation of OM3 allowed at 850 nm by the standards is less than 3.5 dB/km, and less than3.0 dB/km for OM4.

Another factor influencing the cable function is dispersion. Dispersion is the spreading of the signal in time due to the different paths the light can take down the fibre. It has two types: chromatic and modal. In multimode fibre transmission, chromatic dispersion is negligible and the modal dispersion is the limiting factor.

The modal dispersion determines the modal bandwidth that the fibre can operate at and this is the difference between OM3 and OM4. Modal bandwidth represents the capacity of a fibre to transmit a certain amount of information over a certain distance and is expressed in MHz*km. The higher the modal bandwidth the more information can be transmitted. The modal bandwidth of OM3 is 2700 megahertz*km while the mod0al bandwidth of OM4 is 4700 megahertz*km. Thus, OM4 allows the cable links to be longer.

Compared with OM3, OM4 has a lower attenuation and operates at a higher modal bandwidth. That means over OM4 less power is lost during the signal transmission and the signal can be transmitted further or through more connectors (which add to the losses). The following table shows the Ethernet distances at 850 nm supported by OM3 and OM4 respectively.

1Gb 10Gb 40Gb 100Gb
OM3 1000m 300m 100m 100m
OM4 1000m 500m 150m 150m

So why is the standard for 40G only 100m on OM3 and 150m on OM4 compared to 300m and 500m for 10G? There are two reasons. First, when the IEEE 802 standard was created they decided to create a standard based on “relaxed” transceiver specifications so that smaller and lower cost transceivers could be used. Two functions of 10G transceivers (clock recovery and attendant re-timing) are absent in both QSFP+ (40G) and CFP (100G) devices. Second, the standard allows for transceivers with wider spectral width lasers which increase chromatic dispersion (pulse spreading). The quality of transceivers is also a factor.

Which will you choose for your 40/100G network, OM3 or OM4? Except the transmission distance and the cable costs, there are additional factors to consider such as the number of cross connects required and the mix of 40G port to 40G port and 40G port to 10G port. Because 40G signal is transmitted across eight pairs of fibre each with 10G. Similarly, it is important to take into account the likely location of future 100G equipment and the possible 100G to 100G, 100G to 40G and 100G to 10G connectivity requirement.

QSFP+ in the 40 Gigabit Ethernet Fibre Optic Media Systems

There are two 40 Gigabit fibre optic physical medium dependent (PMD) specifications in the standard, which provide 40 Gb/s Ethernet over multimode fibre (MMF) optic cable and single mode fibre (SMF) optic cable. The 40GBase-SR4 short reach fibre optic system sends four lanes of PCS data over four pairs of multimode cables, for a total of eight fibre strands. The 40GBase-LR long-reach system sends four lanes of PCS data four wavelengths of light, carried over a single pair of fibre optic cables.

The first 40 Gb/s transceivers were based on the C form-factor pluggable (CFP) module, 40G CFP transceiver which is a large module capable of handling up to 24 watts of power requirements were based on this module. The CFP modules is specified by a multiagreement.

CFP module, which can be used to provide either a 40GBase-SR4 or a 40GBase-LR4 transceiver. The module is a 40 GBase-LR4 connection is described. The most popular connector for 40 Gb/s interfaces these days is the QSFP+ module: it takes up much less space on a switch or server interface, making it possible for vendors to provide multiple QSFP+ transceiver module for 40GBase-SR4 is provided with a multifibre push-on (MPO) media connector, carrying multiple pairs of fibre optic cables to support the four lanes of data for the short reach fibre standard. The 40GBase-LR4 long-reach system uses a QSFP+ transceiver equipped with a duplex fibre connector for connecting to the single pair of fibre cables.

Recently Molex Incorporated, the world’s largest plug-in companies introduced the QSFP+ interconnect solution designed for a multimode of markets and applications including switches, router, Host Bus Adapters (HBAs), enterprise data centres. high-performance computing (HPC) and storage. Components of the system include the Electromagnetic Interference (EMI) shielding cage, passive cable assembly, active cable assembly, optical MTP cable assembly, optical QSFP+ loopback, and a 38-circuit SMT iPass host connector.

“The QSFP has evolved to QSFP+ to meet 40Gbps data rates just as SFP progressed from SFP to SFP+ for 40 Gbps rates. The original QSFP MSA now resides as INF-8438 and is no longer an appropriate designation for use, being superseded by SFF-8436 in the SFF Committee,” said Jay Neer, advanced technical market manager, industry standards, Molex Incorporatd.

QSFP+ uses a standard 38-circuit iPass SMT host connector with a proven mating interface that connector with a proven mating interface that enables high durability. The iPass SMT host connector with a proven mating interface that enable high durability. The iPass contact design, also implemented in other standards such as PCIe, SAS, SATA, Ethernet and InfiniBand, provides four balanced differential channels featuring class-leading isolation, and bandwidth, with durability cycling up to 250 cycles. The Molex host connector mounts to the PCB beneath a low-profile metal cage that provide latch points and is engineered to provide appropriate EMI protection for the host system port. Optional light pipes and heat sink thermal solutions can be slipped onto the cage when needed.

The QSFP+ cables assemblies are designed to accommodate stacked and ganged connector configurations in extremely high density requirements. They support 40G Ethernet, InfiniBand, SAS and SONET/SDH standards with different data rate options.

The optical QSFP+ MTP cable assemblies and loopbacks meet the QSFP+ interface specification. Cables are constructed with 12-fibre 3.00mm round cable for data centre interconnect cable assembly applications.

The round cable provides much improved cable management over the traditional flat ribbon cable. A robust 4.50mm round optical cable ensure cable integrity and improved cable routing for installations that require connections greater than 25m apart.

QSFP+ breakout cable assemblies are available for SFP+ or patch panel installations. Loopbacks feature a compact housing compatible with module spacing and loop optical transmit ports to receive ports for testing, burn -in, and field troubleshoot.

The related products what mentioned above all can be offered from FS.COM, at the same time, I need to tell you good news that some optical fibre products are working with 30% of the price discount now. Welcome to visit our online store.