Category Archives: Fiber Optic Transceivers

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?

QSFP vs QSFP+

“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+ vs QSFP28

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.

FS.COM QSFP+ vs QSFP28

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
Conclusion

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

Which One to Select, GLC-LH-SM Vs GLC-LH-SMD?

Among so many different Cisco SFP modules, sometimes you may feel confused. Because the differences of some SFP modules are tiny, for instance, Cisco SFP GLC-LH-SM and Cisco SFP GLC-LH-SMD. If you can’t understand the the difference between these two Cisco SFP modules, you don’t know which one to select for your Cisco switch. This article is gonna explain GLC-LH-SM vs GLC-LH-SMD.

Cisco SFP GLC-LH-SM

Cisco SFP GLC-LH-SM is a hot swappable transceiver module that transfers the data rate of 1 Gbps. It’s compliant with IEEE 802.3 1000BASE-LX/LH standard. It supports the link lengths up to 10 km over single mode fibre patch lead at a wavelength of 1310 nm. It can be also applied for short network connection over multimode fibre cable (550 m).
Other features:
Interface: LC duplex
Tx power: -9.5 ~ -3dBm
Receiver Sensitivity < -23dBm
Commercial Temperature Range: 0 to 70°C (32 to 158°F)
DOM Support: No

Cisco SFP GLC-LH-SM

Cisco SFP GLC-LH-SMD

Cisco SFP GLC-LH-SMD is a hot pluggable transceiver module running the data rate at 1 Gbps. This SFP is interfaced with 1000BASE-LX/LH ports. And it can support both single mode and multimode applications.
Other features:
Interface: LC duplex
Tx power: -9.5 ~ -3dBm
Receiver Sensitivity < -23dBm
Commercial Temperature Range: 0 to 70°C (32 to 158°F)
DOM Support: Yes

GLC-LH-SM vs. GLC-LH-SMD Similarities

Cisco SFP GLC-LH-SM and Cisco SFP GLC-LH-SMD are both used for 1Gbps Ethernet network. They support with IEEE 802.3 1000BASE-LX/LH standard and are compatible with each other. The two Cisco SFP modules can be connected with single mode and multimode LC fibre patch lead. If one switch supports Cisco SFP GLC-LH-SM, then it can also support Cisco SFP GLC-LH-SMD. Here are supported switches for these two Cisco SFP modules: Catalyst Express 500, Catalyst Express 520, Cisco ME 3400, Cisco ME 4900 series, Cisco ME 6500 series, Catalyst 2940 series, Catalyst 2950 series, Catalyst 2960 series, Catalyst 2960 S series, Catalyst 2970 series, Catalyst 3560 series, Catalyst 3560 E series, Catalyst 3560-X series, Catalyst 3750 series, Catalyst 3750-E series, Catalyst 3750-X series, Catalyst 4500series, Catalyst 4900 series, Catalyst 6500 series, cisco IE3010 series.

GLC-LH-SM vs. GLC-LH-SMD Differences

The difference between Cisco SFP GLC-LH-SM and Cisco SFP GLC-LH-SMD is that Cisco SFP GLC-LH-SMD has additional letter “D”. What does “D” mean?

There are two kinds of misunderstanding about “D”. Some think “D” represent “duplex”. Cisco SFP GLC-LH-SMD supports duplex interface. But Cisco SFP GLC-LH-SM should be connected with duplex LC patch cable. And nearly all SFP transceiver modules, except copper SFPs, are interfaced with duplex ports. So this understanding is obvious wrong. Some think that “D” means “ruggged”. This opinion is not true either. “Rugged” is abbreviated to “RGD”, for example, Cisco GLC-LX-SM-RGD Compatible 1000BASE-LX/LH SFP 1310nm 10km DOM Transceiver.

“D” of GLC-LH-SMD transceiver has additional support for Digital Optical Monitoring (DOM) capability. From the features stated above, Cisco SFP GLC-LH-SMD can support DOM function while Cisco SFP GLC-LH-SM can’t. DOM provides a diagnostic monitoring interface for optical transceiver modules. DOM supports monitoring of optic output power, optic input power, temperature, laser bias current, and transceiver voltage. When DOM is enabled, the system monitors the temperature and signal power levels for the optical transceiver modules in the specified ports. Console messages and syslog messages are sent when optical operating conditions fall below or rise above the SFP manufacturer-recommended thresholds.

Which to Select, GLC-LH-SM vs. GLC-LH-SMD?

Cisco SFP GLC-LH-SM and Cisco SFP GLC-LH-SMD are very similar and compatible with each other. The only difference is that the latter one has DOM function. SFP with DOM is better for transceiver and system protection. So you are suggested to select Cisco SFP GLC-LH-SMD. Except these two Cisco SFPS, you can find other Cisco compatible SFPs from FS.COM. For more information, please visit out site http://www.fs.com.

Related Articles: 

A Quick Overview of Cisco GLC-LH-SM SFP Module

GLC-LH-SM vs SFP-GE-L: What’s the Difference?

Spend Less on Building 100GbE Network With QSFP28 AOC

Currently 10GbE and 40GbE network are efficient and enough for some users. However, to some large-scale data centres, 40GbE Internet speed can’t meet their demands as the Internet continues to grow in size and traffic. According to research predicts, global data centre Internet protocol traffic will grow by 31% every year within next five years. So 100GbE technology will become the mainstream in the near future. Cisco, Juniper, Arista provide 100GbE switches, routers and supported QSFP28 transceiver, QSFP28 AOC. But many enterprises still can’t upgrade to 100GbE network since the switch and QSFP28 AOC are quite expensive. Don’t worry about the high cost. This article will help you find a way to spend less on building 100GbE network with QSFP28 AOC.

QSFP28 AOC

100GbE QSFP28 AOC is composed of an OM4 multimode cable connecting two QSFP28 connectors on each end. The form factor design is easy for plugging and removal. The QSFP28 AOC is compliant to the QSFP MSA (multi-source agreement). QSFP28 AOCs support 100G QSFP28 standards and are available in various lengths (usually from 1-30 metres). 100G QSFP28 AOCs provide an affordable low-power alternative to interconnect 100G QSFP28 ports in data centre applications. It’s useful for simplified intra rack and inter rack configurations. The following table lists 100GbE QSFP28 AOC of several famous brands.

QSFP28 AOC

Brands QSFP28 AOC Price
Cisco QSFP-100G-AOC (1m-30m) Above US$ 1,000
Arista AOC-Q-Q-100G (1m-30m) Above US$ 3,000
Juniper JNP-QSFP28-AOC (1m-30m) Above US$ 2,000
FS.COM QSFP28 AOC (1m-30m) From US$ 540 to US$ 630

Table 1. QSFP28 AOC Price Comparison

Switches Supporting QSFP28 AOC

Cisco, Arista, Juniper are three famous fibre optic transceiver manufactures. Transceiver modules and switches of these brands are very common in the market. As the demand for 100GbE data centre keeps moving, these manufactures produce switches including 100GbE QSFP28 ports. Here I list four switches which can support QSFP28 AOC, Cisco Nexus 3232C, Arista 7500R, Juniper QFX5110 and FS.COM S5850-48S2Q4C.

  • Cisco Nexus 3232C—The Cisco Nexus 3232C switch is a low latency, dense, high-performance 100GbE switch designed for data centre. It can not only meet customers’ current network needs but also suitable for future applications such as big data, cloud and virtualization. Each of 32 100GbE QSFP28 ports can operate at 10, 25, 40, 50, 100 GbE.
  • Arista 7500R—Arista 7500R switches (7500R-36CQ, 7500R-36Q, 7500R-48S2CQ) is designed to lower power per 100GbE port and produce more reliable and dense network. The switches are available in a compact system design of 12, 8 and 4 slot. 7500R-36CQ has 36-port 100GbE QSFP line card. 7500R-36 owns 1/10GbE line card with two 100GbE QSFP28 ports. 7500R-48S2CQ is available with up to 6 100GbE QSFP28 ports.
  • Juniper QFX5110—Juniper provides two switches with 100GbE port: QFX5110-48S and QFX5110-32Q. QFX5110-48S is a 10GbE/100GbE data centre access switch offering 48x10GbE SFP+ port and 4x100GbE QSFP28 ports. QFX5110-32Q offers up to 32x40GbE QSFP+ ports, or 20x40GbE QSFP+and 4x QSFP28 ports.
  • FS.COM offers two switches for 100GbE network: S5850-48S2Q4C and S8050-20Q4C. S5850-48S2Q4C provides 48x10GbE SFP+ ports, 2x40GbE QSFP+ ports and 4x100GbE QSFP28 ports. S8050-20Q4C has 2x40GbE QSFP+ ports and 4x100GbE QSFP28 ports.
Switch Brands Model Supported QSFP28 AOC Switch Price
Cisco Nexus 3232C QSFP-100G-AOC (1m-30m) About US$ 19,500.00
Arista 7500R-36CQ 100GBASE-AOC(3m to 30m) Average US$ 60,000.00
7500R-36Q
7500R-48S2CQ
Juniper QFX5110-48S QSFP28 AOC (10 m) Above US$ 16,500.00
QFX5110-32Q
FS.COM S5850-48S2Q4C Generic QSFP28 AOC (1m-30m) US$ 6,900.00
S8050-20Q4C

Table 2. Price Comparison of Switches Supporting QSFP28 AOC

Spend Less With FS.COM Switches and QSFP28 AOC

Based on Table 1 and Table 2, to build a 100GbE network with QSFP28 AOC will cost a lot, especially when you require for products from Cisco, Arista and Juniper manufacturers. By comparison, you can see the price of FS.COM switches for 100GbE network and QSFP28 AOC is quite lower. So FS.COM can help you spend less on building 100GbE network with QSFP28 AOC. But if you have already owned Cisco, Arista or Juniper switches, you can buy compatible QSFP28 AOCs which are more cost-effective and have been tested to assure 100% compatibility.

Related FS.COM News:  FAQs about FS.COM 100G Switches

How to Understand Tx Power vs. Rx Power of a Fibre Transceiver?

As we all know, single mode fibre optic transceiver is designed for long distance data transmission and multimode fibre optic transceiver is for short distance link. How to calculate the specific distance that a fibre optic transceiver can support at a certain occasion? What factors are crucial to the transmission distance? Do you have any idea of Tx power (transmit) and Rx power (receive) level of a fibre optic transceiver? This article will show you by introducing 10GBASE-SR SFP+ and 10GBASE-LR SFP module.

Tx Power and Rx Power of a Fibre Transceiver

First, let’s understand the most two important factors of the fibre optic transceiver: Tx power and Rx power. The optical Tx power is the signal level leaving that device and it should be within the transmitter power range. The Rx power is the incoming signal level being received from the far end device and it should fall within the receive power range.

10GBASE-SR SFP+ is a multimode fibre transceiver and can support the distance of 300 m over OM3 multimode fibre patch lead. While 10GBASE-LR SFP module is a single mode type and can run the network distance up to 10 km over single mode fibre patch leads. Before purchasing 10GBASE SFP+ module, you must carefully read the product details. The following lists the product details about 10GBASE-SR SFP+ and 10GBASE-LR SFP module from Fiberstore. As showing below, Tx power of this Cisco compatible 10GBASE-SR SFP+ is between -7.3 dBm and -1 dBm. The maximum receive power is below -11.1 dBm. With regard to Cisco compatible 10GBASE-LR SFP module, Tx power is from -8.2 to 0.5 dBm and the maximum Rx power is -14.4 dBm.

Tx Power and Rx Power of 10GBASE-SR SFP+

Tx Power and Rx Power of 10GBASE-SR

Tx Power and Rx Power of 10GBASE-LR SFP+ Module
Tx Power and Rx Power of 10GBASE-LR
Tx Power and Rx Power VS. Optical Power Budget

To calculate the specific distance of a fibre optic transceiver, we need to know its optical power budget (maximum allowable loss).

Optical power budget = Tx power – Rx power

Therefore, according to the Tx power and Rx power, we can calculate the maximum allowable loss of 10GBASE-SR SFP+ and 10GBASE-LR SFP module.

Optical Power Budget of 10GBASE-SR SFP+

Min Tx Power = -7.3 dBm
Max Rx Power = -11.1 dBm
Optical power budget (maximum allowable loss) = (-7.3 dBm) – (-11.1 dBm)=3.4 dBm

Optical Power Budget of 10GBASE-LR SFP+ Module

Min Tx Power = -8.2dBm
Max Rx Power = -14.4 dBm
Optical power budget (maximum allowable loss) = (-8.2 dBm) – (-14.4 dBm)=6.2 dBm

Tx Power and Rx Power VS. Transmission Distance

Except optical power budget, we have to consider other factors including the link length, fibre optical connectivity components, fusion splicing points and some unpredictable fibre attenuation caused by fibre patch lead bending (usually the attenuation is about 3 dB). The loss of each connector is 0.6 dB and 0.1 dB of each fusion splicing point. Suppose we use 10GBASE-LR SFP+ module to build a network covering 2 connectors, 4 fusion splicing points. This module is interfaced with LC single mode fibre patch cord. If the single mode fibre cable has the wavelength of 1310 nm, the cable loss is about 0.35 dB per kilometer.

The worst optical loss = Power Budget – Total Optical Power Loss=6.2 dB – 1.2dB (2×0.6 dB) – 0.4dB (0.1×4) – 3dB (safety factor) = 1.6 dB
Worst case distance = {Worst case OPB, in dB} / [Cable Loss, in dB/km]=1.6dB/0.35dB/km
So we can get 10GBASE-LR SFP+ module can support at least 4.57 km at this occasion. Data transmission distance is mainly influenced by the optical power budget and fibre cable loss. From the above content, the optical power budget of 10GBASE-SR SFP+ is smaller than that of 10GBASE-LR SFP+ module. The more the optical power budget, the further the fibre transceiver can support. What’s more, the cable loss of multimode fibre cable is larger than that of single mode fibre cable. Obviously 10GBASE-LR SFP+ module can support longer link distance than 10GBASE-SR SFP+.

network building

Note: The optical power budget is based on a theoretical calculation, and is just for reference. The transmission distance should be calculated based on the power budget of fibre transceiver module tested on the switch and some practical attenuation.

Conclusion

Tx power and Rx power level of a transceiver are the main factors of transmission distance. The more the optical power budget, the better the transceiver. Before purchasing a transceiver, you’d better calculate the optical power budget according to transceiver module details.

Related Article:  10G SFP or 10GBASE-T SFP for 10GbE Network?

How to Check SFP Module Optical Signal Strength?

Why not Use Third-party Fibre Transceivers for Ubiquiti Switches?

Ubiquiti is famous for its switches such as Edge Switch, Edge Router, UniFi switch. Last year, this manufacturer officially released its own SFP and SFP+ fibre optic transceivers which are compatible with their switches. At the same time, it’s said that fibre transceivers from some fibre optic transceiver manufacturers such as Fiberstore can support Ubiquiti switches. This article will discuss what kind of third-party fibre transceivers are compatible with Ubiquiti switches and which fibre optic transceiver manufacturers is the most reliable.

Ubiquiti Fibre Transceivers

Ubiquiti switches are specially designed for 1G and 10G network. They didn’t produce their own fibre transceivers until last year. They only provide a small amount of single mode and multimode fibre transceivers. UF-MM-1G and UF-SM-1G-S are designed for SFP ports on Ubiquiti switches. And fibre transceivers like UF-MM-10G, UF-SM-10G, UF-SM-10G-S are for Ubiquiti switches’ SFP+ ports.

Third-party Fibre Transceivers For Ubiquiti Switches

Except their own SFP or SFP+ transceivers, those from other fibre optic transceiver manufacturers like Cisco, Dell, HP, Finisar, Brocade have been tested to be compatible with Ubiquiti switches by some users. Cisco, the world famous fibre optic transceiver manufacturer, has seven SFPs supporting Ubiquiti switches, Cisco GLC-LH-SM 30-1299-01 SFP, Cisco GLC-SX-MM, Cisco GLC-SX-MM 1000BASE-SX SFP, Cisco SFP-H10GB-CU1M, Cisco MGBSX1 Gigabit SX Mini-GBIC SFP Transceiver and Cisco GLC-T. Besides, for 10G network, Cisco SFP-10G-SR can be plugged in SFP+ ports on their switches.

Fiberstore Fibre Transceivers For Ubiquiti Switches

Fiberstore also has a wide variety of SFP and SFP+ transceivers compatible for Ubiquiti switches. Users have recommended some SFPs and SFP+s from Fiberstore, for instance, SFP1G-LX-31 1310nm (single mode SFPs), SFP-1G85-5M (multi-mode), SFP-GB-GE-T Module, SFP-10G85-3M (multi-mode).

Comparison Between Ubiquiti and Fiberstore Fibre Transceiver

There are so many third-party transceiver manufacturers providing compatible fibre transceivers fro Ubiquiti switches. But which fibre transceiver supplier should you choose? The answer is Fiberstore. Now let’s see why Fiberstore is more advantageous by comparing Ubiquiti with Fiberstore fibre transceiver.

    • Fibre Transceiver Category—Ubiquiti has only one single mode SFP and one multimode SFP. As to SFP+ transceivers, there only two single mode modules and one multimode module. The fibre transceiver category is very limited. While users have plenty of choices for SFPs and SFP+s from Fiberstore. As mentioned above, Ubiquiti switches support some fibre transceivers from third-party fibre optic transceiver manufacturers. Fiberstore offers many compatible brands like Cisco, Dell, HP, Finisar, Brocade, etc. Those SFPs and SFP+s have been tested to be suitable for Ubiquiti switches.
    • Fibre Transceiver Quality—Some fibre optic transceiver manufacturers produce SFP and SFP+ transceivers with low price. However, the quality of those fibre transceivers can’t be assured. In our test centre, we have switches from Cisco, Dell, Extreme, Juniper and other famous brands. Every fibre transceiver offered by Fiberstore before shipping has to go through strict test to assure 100% compatibility and high performance.

fs fiber transceiver

    • Fibre Transceiver Price—Except fibre transceiver quality, fibre transceiver price is another important factor to be considered. Compare fibre transceiver price of Fiberstore with that of other fibre optic transceiver manufacturers, it’s obvious that Fiberstore has more advantages. That’s one of the reasons why Fiberstore wins popularity among customers. You can check the following screenshots about the feedback from customers.


customer review2

Conclusion

If you have to purchase fibre transceiver for your Ubiquiti switches, you can get SFP or SFP+ from Ubiquiti. Or you can buy from third-party fibre optic transceiver manufacturers. How to choose a reliable supplier from so many fibre transceiver manufacturers? When buying fibre transceiver, the quality, price, and after-sales service should be considered. As one of fibre optic transceiver manufacturers, Fiberstore is suggested to be a good choice for fibre transceiver needs. For more information about FS.COM fibre transceiver, please visit our site www.fs.com/uk or contact us via sales@fs.com.

Related article of my blog: Transceiver Solutions for Ubiquiti UniFi Switches

QSFP+ to 4xSFP+ AOC and QSFP+ MTP Breakout Cable Solution

Migration from 10G to 40G is an inevitable trend in data centre. Migration means you need new QSFP+ transceiver modules, fibre patch leads and other equipment. Common two methods to migrate from 10G to 40G for short distance are QSFP+ to 4xSFP+ AOC and QSFP+ MTP breakout cable solution. When you come across this issue, it’s hard to tell which one is better. This article will introduce their difference and tell you how to make the right decision.

40G QSFP+ to 4xSFP+ AOC

40G QSFP+ to 4xSFP+ AOC (active optical cable) is composed of a QSFP+ connector on one side and four individual SFP+ connectors on the other side. The QSFP+ connector (40Gbps rate) offers four parallel, bidirectional channels and each operates at up to 10.3125 Gbps. The QSFP+ connector can be installed into QSFP+ port on the switch and feed up to four 10G SFP+ links. And the link lengths can reach 100 meters on OM3 fibre. It’s a cost-effective interconnect solution for 40G and 10G switches and servers.

40G QSFP+ to 4xSFP+ Breakout AOC

QSFP+ MTP Breakout Cable

The other common solution for 10G to 40G short distance migration is to use MTP breakout cable and of course corresponding transceivers. How to achieve the connection? You’re gonna need 40GBASE-SR4 QSFP+, MTP to LC breakout cable and 10GBASE-SR SFP+. Here we are going to explain 40GBASE-SR4 QSFP+ and MTP breakout cable in details.

First, 40GBASE-SR4 QSFP+ is designed for 40 Gigabit data centre and can support the link length of 100 m and 150 m respectively on laser optimised OM3 and OM4 fibre cables. This module offers 4 independent channels for transmitting and receiving. Each lane is capable of running 10Gbps signal and is compliant to IEEE 10GBASE-SR specification. Connecting with 12-fibre MTP/MPO cables, it can support 40Gbps network. Or combine 40GBASE-SR4 QSFP+ with 4x10G breakout cable and send data to four 10GBASE-SR SFP+.

Second, MTP breakout cable is suitable for high density network. It’s specifically designed for fast Ethernet, fibre channel, data centre and gigabit Ethernet application. QSFP+ MTP breakout cable is used for a direct connection between QSFP+ to 4xSFP+ ports with no patch panels or intermediate trunks in between. On one side, it’s an MTP connector with 8 or 12 fibres. On the other side, there are 4 duplex LC connectors. Each fibre cable transmits 10Gbps.

MTP breakout cable

Differences of Two Solutions

Two methods of 10G to 40G migration over short distance have been introduced in above content. Comparing the two different solutions, you can find some obvious differences. The following lists some points for your convenience to make suitable decision.

  • Price—The second solution needs at one QSFP+, 4 SFP+ and an MTP breakout cable. The price of these devices is higher than 40G QSFP+ to 4xSFP+ AOC. So 40G QSFP+ to 4xSFP+ AOC is cheaper.
  • Complexity—The second solution seems more complicated since it needs more optical equipment. You need to order and manage cables.
  • Distance—40G QSFP+ to 4xSFP+ AOC can only support the distance up to 100 m. While using MTP breakout cable, the link distance can reach 150 m over OM4 cable.
Conclusion

You must have a full understanding of these two solutions. 40G QSFP+ to 4xSFP+ AOC is easier and cheaper than MTP breakout cable. If you’re a new technician and have tight budget, you can buy AOC cable. But if you don’t care too much about money, you can select 40GBASE-SR4 QSFP+ and MTP breakout cable to get a little longer link length. Hope this article can help you make the right decision.

What Distance Can 100G QSFP28 Transceiver Support?

The rapid growing bandwidth keeps driving the need for 100G transceivers to build data centres, enterprise, long-haul networks. Just as 1G, 10G optical modules, 100G QSFP28 transceivers also have single-mode and multimode categories to support short and long distance network links. So what kind of QSFP28 transceivers are included? What distance can each QSFP28 support?

100G QSFP28 – Supported Distance Below 1km

Multimode 100G QSFP28 modules are used for short distance applications, such as QSFP28 Cisco QSFP-100G-SR4-S 100GBASE-SR4 transceiver. It provides 100GBASE-SR throughput at a wavelength of 850 nm by connecting with multimode MTP/MPO cable. It can support the link lengths up to 70 m over OM3 MPO fibre patch lead and 100 m over OM4 MPO fibre patch lead.100g qsfp28 sr4

But there is a special 100G QSFP28 transceiver–QSFP-100G-PSM4-S. This QSFP28 is a single-mode transceiver. It carries 100G data over 12-fibre single-mode MPO fibre patch cords. However, the maximum link lengths it can support is only 500 metres.

100G QSFP28–Supported Distance From 1km-10km

To support long distance signal transmission, single-mode transceivers are generally selected. The following will list some 100G QSFP28 modules which can reach the link distance from 1 km to 10 km.

QSFP28 100GBASE-CWDM4. This transceiver applies WDM multiplexing and demultiplexing technique and carries 100G Gigabit Ethernet signal over four wavelengths. Different from the above two 100G QSFP28 optics, it’s configured with duplex LC interfaces. With QSFP28 100GBASE-CWDM4 modules, you can build networks with link lengths up to 2 km over single-mode duplex LC patch cords.

QSFP28 100GBASE-LR4. This hot-pluggable 100G QSFP28 form factor can support 103.1Gbps data rate. It’s compliant with the QSFP28 MSA and IEEE802.3ba 100GBASE-LR4. The 100G data is transmitted over four wavelengths. Because of multiplexing and demultiplexing within this QSFP28 transceiver, it matches duplex LC patch cords. And it can support links up to 10 km over single-mode LC fibre cable.

100g qsfp28 lr4

100G QSFP28–Supported Distance Over 10km

In fact, 10km link lengths of 100G can’t meet users’ demands. So 100G QSFP28 which can support over 10km lengths are needed to build long-haul network. Due to the optic package size and the maximum power, the distance supported by 100G QSFP28 transceivers are restricted. Vendors are required to research and develop optics that allow for existing high power components and devices to consume lower power in a smaller space. It’s said there are 100G QSFP28 ER4 and 100G QSFP28 ZR4 transceivers in the market. Each can support the maximum network link lengths up to 30 km and 80 km. But consumers can’t easily get those 100G QSFP28 modules. But we believe that ER4 and ZR4 technology will be available in the market sooner or later.

At present, if your switch ports are QSFP28 and you need to build 100G network links over 10km, you are suggested to apply amplification technology. The other method is 100G CFP ER4 that support 40km link lengths. Of course your switch port should be CFP or you can find a device to convert QSFP28 to CFP.

Conclusion

Now people can get 100G QSFP28 transceivers for link lengths up to 10 km. Yet not too many transceiver vendors have enough stocks. In the Internet era, what is important is the speed. Thus, seek for reliable vendors who have huge stocks of QSFP28 like FS.COM. And we will release 100G-QSFP28-ER4 and 100G-QSFP28-ZR4 in the future to support longer distances.

 

How to Select Fibre Patch Lead for 40G QSFP+ Modules?

As the speed changes from 1 to 10 Gbps and now increases from 10 to 40 Gbps and even 100 Gbps, data centres develop into more complex systems. So different optical technologies and cabling infrastructure are required. For 40G data rates, the special transceiver module is QSFP+ (Quad Small Form-Factor Pluggable Plus). To build 40G data centres, you need to select suitable fibre patch lead for 40G QSFP+ Modules. But how?

40G transmission network needs advanced switch, matched patch leads and transceiver modules. The quality of these connections can largely affect the reliability and stability of the whole 40G network. However, connectivity of 40G is much more complex than ever. Thus, selecting the proper fibre patch cables for 40G network is more difficult and becomes a big issue in 40G migration. As mentioned, QSFP+ transceivers are suggested for 40G, this article will provide as detailed as possible about fibre patch lead selection for 40G QSFP+ transceivers.

40G QSFP+ transceivers

Patch cable is very important to 40G network not only because the switch connections necessity, but also because of the transmission principle of the fibre optic signals and the high density trend of 40G transmission. Several important factors like cable, connector and switch port should be taken into account when selecting patch leads for 40G QSFP+ transceivers.

Single-mode or Multimode Fibre Patch Lead

Fibre patch lead is essential for the network performance. Optical signals perform differently when information transforms through the cables with different wavelengths. When people buy fibre optical patch leads for 40G QSFP+ transceiver, they often ask if a 40GBASE universal QSFP+ transceiver working on wavelength of 850nm can be used with OM1 patch leads. The answer is yes, but not suggested. Why? As the optical signal transmission distance gets shorter, the data rate increases. The transmission distance and quality would be limited by using OM1 optical cable with 40G QSFP+ transceiver. OM1 cable is only suggested for 100 Mb/s and 1000Mb/s transmission. Two upgraded cables—OM3 and OM4 are suggested for 40G QSFP+ transceivers in short distance.

IEEE has announced standards for 40G transmission in both long distance and short distance, which are 40GBASE-LR4 and 40GBASE-SR4. (LR stands for long reach and SR stands for short-reach and). For long reach, single-mode fibre is suggested for 40G transmission with the distance up to 10 km. For short reach, multimode fibre—OM3 (up to 100 metres) and OM4 (up to 150 metres) is suggested for 40G transmission. OM3 and OM4, which are usually aqua-coloured, are accepted economic solutions for 40G in short distance with lower insertion loss and higher bandwidth.

MTP or LC Fibre Patch Lead

The connector type of the patch leads should depend on the interface of 40G QSFP+ transceiver. Now there are two interfaces commonly adopted by 40G QSFP+ transceiver and they are MTP and LC. Usually 40G QSFP+ transceiver with MPO interface is designed for short transmission distance and LC for long transmission distance. However, several 40G QSFP+ transceivers like 40GBASE-PLR4 and 40GBASE-PLRL4 have MPO interfaces to support long transmission distance.

mtp and lc connectors for qsfp+

High density is the most obvious characteristic of 40G transmission, which is largely reflected in the MTP connectors on patch leads used with 40G QSFP+ transceiver. As QSFP+ transceiver uses four 10G channels, MTP cable which uses 4 pairs of fibres with can provide a time-save and stable solution for 40G QSFP+ transceivers.

Besides, 40G QSFP+ transceiver with LC interface is also available. This type of QSFP transceiver uses four lanes with each carrying 10G in 1310nm window multiplexed to achieve 40G transmission. For this type, patch cable with duplex LC connector should be used.

Switch Port

The importance of network flexibility gradually reveals as the speed of Ethernet increases. Cabling options for 40G network are 40G QSFP+ to 40G QSFP+, 40G QSFP+ to SFP+. It’s very common that 40G ports is needed to be connected with 10G port. In this case, fan out patch cable with MTP connector on one end and four LC duplex connectors on the other end is suggested.

Factors like single-mode or multimode fibre jumpers, fibre patch lead connector and switch port are important in selecting the right patch leads for 40G QSFP+ transceivers. They are closely related to the transmission distance, network flexibility and reliability of the whole 40G network. But in practical cabling for 40G QSFP+ transceivers, there are more need to be considered. Planning and designing takes a lot of time and may not achieve results good enough. However, FS.COM can solve your problems with professional one-stop service including the cost-effective and reliable network designing and 40G products.

Save Cost by Using BiDi Transceivers

As usual, optical transceivers such as SFP or SFP+ use two fibres to transmit data between switches. One fibre is used to transmit data to the network equipment and the other fibre is utilised to receive the data. As to the transceiver modules of high speed data rate like QSFP-40G-SR4 and QSFP-40G-ESR4, they need more fibres. Is there any technology allowing transceivers to transmit and receive through one single optical fibre or two fibres for QSFP+? In fact, this can be achieved by Bidi transceivers.

What Is BiDi Transceiver?

The answer is yes. And that kind of transceiver is called BiDi transceiver. Bidi (Bi–Directional) transceiver is also known as WDM transceiver, because it applies wavelength division multiplexing (WDM) couplers, also called diplexers, which combine and separate data transmitted over a single fibre based on the wavelengths of the light.

BiDi Transceiver Advantage

Compared with traditional transceiver modules, BiDi transceivers can cut your cost on fibre cabling infrastructure by requiring fewer fibre cables, reducing the number of fibre patch panel ports and saving fibre cable management space. Based on the obvious advantages, you should deploy BiDi transceivers in your network. Here will recommend you several kinds of BiDi transceivers of 1Gbps, 10Gbps and 40Gbps.

BiDi Transceiver Categories

BiDi SFP transceivers transmit and receive optical signal through a single fibre on the wavelengths of 1310 nm & 1490 nm, 1310 nm & 1550 nm, 1490nm & 1550 nm. BiDi SFPs include the supportable data rate of 100Mbps and 1000Mbps. Take the Cisco GLC-BX-U compatible 1000BASE-BX-U BiDi SFP as an example. The wavelengths of the BiDi SFP are 1310 nm and 1490 nm. It can support the link lengths of 10 km over LC simplex fibre patch cable. As shown in the following figure, a pair of Cisco GLC-BX-U compatible BiDi SFPs are linked via a single LC simplex fibre patch cable to build the direct connection of two Cisco Catalyst 4948E-F switches.

cisco-glc-bx-u

Bidi SFP+ transceiver is enhanced SFP designed to support 10Gbps data rate with link lengths up to 80 km over one fibre. It uses WDM technology sharing 1270 nm & 1330 nm. Take a look at the figure below. It’s about the direct connection for 10G BiDi SFP+ in room wiring. The two Cisco SFP-10G-BXU-I compatible 10GBASE-BX10-U SFP+ transceivers are plugged into Cisco Nexus 9396PX switches. The connection is achieved by using an LC simplex fibre patch cable. It’s a simplest and cost-effective way to build 10 Gigabit Ethernet connectivity for data centre.

cisco-sfp-10g-bxu-i

BiDi QSFP+

40G BiDi QSFP+ transceiver is specially designed for high density data centre. With QSFP+ BiDi transceivers, you can get 40Gbps network over 10Gbps cable. In this way, you don’t need to replace all 10G two-fibre patch cables with 8-fibre MTP/MPO patch cable if you need network upgrade. In Figure 3, we use Cisco QSFP-40G-SR-BD compatible 40GBASE-SR BiDi transceivers for the direct connection of two switches. Instead of applying 40G MTP patch cable, we can just plug the common LC-LC fibre patch cable into the transceivers to get 40Gbps network. It saves you lots of costs.

cisco-qsfp-40g-sr-bd

Warm Tips: When you buy a BiDi transceiver, you may notice wavelengths are labeled on the BiDi transceivers like 1270nm-TX/1330nm-RX or 1270nm-RX/1330nm-TX. From this perspective, you can see this type of transceivers should be used in matched pairs, with their diplexers tuned to match the expected wavelength of the transmitter and receiver that they will be transmitting data from or to.

Summary

BiDi transceivers may be more expensive than common transceiver modules, but they can save you the cost on fibre cables from the long run. FS offers BiDi transceivers of various data rates which are highly compatible with some famous brands. If you plan to purchase BiDi transceivers for building or upgrading your network, you can visit our site www.fs.com.

Related Article: A Brief Introduction of BiDi SFP Transceiver

What Should You Know About Fibre Channel?

Before Fibre Channel appears, SCSI (small computer system interface) was used as the transmission interface between servers and clustered storage devices. But as the high speed demands keep increasing, Fibre Channel replaces SCSI inevitably due to its higher transmission data rate, flexibility, and long distance. This article is going to introduce you some details about Fibre Channel.

What Is Fibre Channel?

Fibre Channel, short for FC, is a technology for transmitting data between computer devices at data rate of 1, 2, 4, 8, 16, 128 Gbps. It’s mainly used in storage area networks (SAN) in commercial data centres. It’s useful for connecting computer servers to shared storage devices and for interconnecting storage controllers and drives.

Fibre Channel Transceivers

Except optical fibre cable, Fibre Channel transceiver is the other vital equipment to connect the Fibre Channel network in data centres. It provides the interface between Fibre Channel systems and the optical fibres of the SAN. FS.COM offers SFPs and SFP+s that are compatible with Fibre Channel. Fiberstore Fibre Channel SFPs support the distance up to 80km and the data rate of 2G/4G. As to our Fibre Channel SFP+ transceivers, they can support the data rate up to 8Gbps and 10Gbps. In Fiberstore, you can also find some compatible brands of FC transceivers including Cisco, Juniper, Brocade, HPE, etc. What’s more, all these modules have been tested to assure 100% compatible. For your information, the following table shows some hot FC transceivers for 2G/4G and 8G/10G network applications.

Model Description
37656 2G Fibre Channel SFP 1310nm 10km DOM Transceiver
15376 Cisco DS-SFP-FC8G-ER Compatible 8G Fibre Channel SFP+ 1550nm 40km DOM Transceiver
15231 Cisco DS-SFP-FC8G-SW Compatible 8G Fibre Channel SFP+ 850nm 150m DOM Transceiver
15386 HPE (ex QLogic) AJ718A Compatible 8G Fibre Channel SFP+ 850nm 150m DOM Transceiver
39630 HPE (ex Brocade) AJ716B Compatible 8G Fibre Channel SFP+ 850nm 150m DOM Transceiver
35932 Brocade XBR-000163 Compatible 8G Fibre Channel SFP+ 850nm 150m DOM Transceiver
fibre-channel-sfp-sfp-plus
Transfer to High Speed Fibre Channel

However, as the need for high-bandwidth never stops increasing, the data rate of 2G, 4G or even 8G can’t meet the high speed requirements. So many data centres move to higher Fibre Channel standards, for example, 16G Fibre Channel. 16G FC links increase the network speed twice as 8G FC and 40% faster than 10G FC. The transition to 16G FC makes data transfer smoother, quicker and cost-effective from the good side. But from the other side, the transition still faces some challenges. There might be some data communication error rates that may affect the network performance. And the physics of 16G FC can possibly bring some new restrictions on fibre cabling and transceiver modules. Therefore, before starting to transfer to higher speed Fibre Channel infrastructure, you should better follow the tips listed below.

First, cleaning issue. In fibre optics connection, contamination is thought as a big problem which may lead to link failure. So you should clean all the transceiver modules, connectors and other cable junctions to ensure there is no contamination in the fibre optic connection. Some fibre testers and cleaning tools are necessary for your cleaning work.

Second, analyze the optical power budget between transmit and receiver ports. It requires that the power margin (transmit power minus power loss during the data transmission through the cable) should be more than the receiver power of the optical transceivers. At the same time, it also should meet the FC protocol specification.

Third, measure the light level on the transmitting side and receiving side. You can use suitable fibre optical light source or optical power meter to measure the power level on critical links. If the power level were not in the right station, check whether the cable length is suitable or cable bend radius reaches the maximum. Then you are suggested to purchase customized bend insensitive fibre cable for your special use.

Summary

Fibre Channel is commonly used for the connection of SAN in enterprise storage. You can find 2G/4G FC SFPs, 8G/10G FC SFP+ modules and matching fibre patch leads from FS.COM. If you need to upgrade your Fibre Channel network to 16G or even higher, remember the above tips and make sure the 16G FC are compatible with 4G FC and 8G FC.

Related article: Netgear AGM731F Compatible SFP for Gigabit Ethernet and Fibre Channel Applications