Tag Archives: 40G QSFP+

How to Take Full Advantages of Switches in Data Center: A Case Study of IBM G8264 Switch

During data center upgrading or migration to higher data rate like 40G/100G, the network designer is always pursuing for flexibility. This is because devices or cabling components with great flexibility can not only decrease the cost for upgrading, but also provide more possibilities for the data center in the future. Switch has always been the most important device data center. Thus, a flexible switch should support a variety of transmission media and data rates, which could have significant positive influence during data center upgrading on cabling and costs. IBM G8264 switch is such a switch that is specially designed for data center, which is suggested to be used at layer 2 or layer 3, providing non-blocking line-rate, high-bandwidth switching, filtering, and traffic queuing without delaying data. However, to make full use of these switches, you should select proper connection components and cabling plans. This post will take IBM G8264 switch as an example to illustrate how to take full advantages of the switches in data center.

Understand Your Switch—IBM G8264 Switch

The first step to make full use of a switch is to have a full understanding of the switch you are using. There are many ways to understand your switch. While the most direct method is to understand the ports on the switches. This method also works for IBM G8264 switches. As shown in the following picture, which is the front panel of IBM G8264 switch, the most outstanding part of the switch is the 48 SFP/SFP+ ports. It occupied most space on IBM G8264 switch front panel. These ports can support data rate of 1G/10G. Four QSFP+ ports for 40G are beside these SFP/SFP+ ports. There are three another ports for other use on the from panel: one 10/100/1000 Ethernet RJ45 port for out of band management, one USB port for mass storage device connection and one mini-USE console port for serial access.

IBM G8264 switch port information

IBM G8264 Connection in Data Center

It is clear that IBM G8264 switch can support data rate of 1G, 10G and 40G. The following parts illustrate how to connect IBM G8264 with the target devices in 1G, 10G, and 40G network separately in details. During the cabling in data center, distance is always a factor that cannot be ignored. The transmission distance required, can largely decide the cabling components selection.

1G Connection of IBM G8264 Switch

To accomplish the 1G connection of IBM G8264 switch and target devices, there are several methods according to transmission distance and transmission media (fiber optic or copper). For distance up to 100 meters, RJ-45 1000BASE-T SFP transceivers with UTP Cat5 cables are suggested, cause they are based on copper and is cheaper than fiber optic components. However, if you want reach a longer distance with good transmission quality, it would be better to use fiber optic cable and optical transceiver. By using 1000BASE-SX SFP optical transceivers with multimode fiber, the transmission distance is up to 220 (62.5 μ multimode fiber) meters and 550 meters (50 μ multimode fiber). For long distance transmission, single-mode fiber optic cables are suggested to be used with 1000BASE-LX SFP optical transceivers, which can connect IBM G8264 switch with the target devices that are 10 kilometers far away. The following chart is the detailed product solutions for IBM G8264 1G connection.

Transmission Media Module Cable & Connector Distance
Copper Cable BN-CKM-S-T: SFP 1000BASE-T copper transceiver RJ45, Cat5 cable 100 m
Fiber Optic Cable BN-CKM-S-SX: SFP 1000BASE-SX optical transceiver LC duplex, MMF 220 m(50μ multimode fiber)
550 m(62.5μ multimode fiber)
BN-CKM-S-LX: SFP 1000BASE-LX optical transceiver LC duplex, SMF 10 km

10G Connection of IBM G8264 Switch

As mentioned, IBM G8264 switch supports 10G configuration. For 10G, there are mainly two methods: using DACs (direct attach cables) or using transceivers and patch cords. The beauty of using DAC is the eliminating of transceivers and reduction of cost. However, the transmission distance is limited to 7 meters by using DACs. If longer distances are required, 10GBASE-SR transceiver used with OM3 multimode fiber can support transmission distance up to 300 meters. If 10GBASE-SR transceiver is used with OM4 fiber optic cable, distance up to 400 meters could be reached. Using 10GBASE-LR transceiver with single-mode fiber optic cable, IBM G8264 switch can be connected with target devices that are 40 kilometers away.

IBM G8264 switch and 40GBASE QSFP+ transceiver

If the 10G ports number cannot satisfy the requirements, the one QSFP+ port on IBM G8264 can be split into four 10G ports, by using QSFP+ DAC breakout cables for distances up to 5 meters. For distances up to 100 meters, optical MTP-to-LC break-out cables can be used with the 40GBASE-SR4 transceiver. Kindly check the following table for IBM G8264 switch 10G cabling components solutions.

Data Rate Modules Cable & Connector Distance
10G-10G Connection BN-SP-CBL-1M: SFP+ Copper Direct Attach Cable (1 meter) 0.5-7 m
BN-SP-CBL-3M: SFP+ Copper Direct Attach Cable (3 meter)
BN-SP-CBL-5M: SFP+ Copper Direct Attach Cable (5 meter)
BN-CKM-SP-SR: SFP+ 10GBASE-SR Short Range Transceiver LC duplex, MMF 300 m(OM3)
400 m(OM4)
BN-CKM-SP-LR: SFP+ 10GBASE-LR Long Range Transceiver LC duplex, SMF 40 km
40G-10G Connection BN-QS-SP-CBL-1M: QSFP+ DAC Break Out Cable (1 meter) 5 m
BN-QS-SP-CBL-3M: QSFP+ DAC Break Out Cable (3 meter)
BN-QS-SP-CBL-5M: QSFP+ DAC Break Out Cable (5 meter)
BN-CKM-QS-SR: QSFP+ 40GBASE-SR Transceiver MTP-to-LC break-out cables 100 m

40G Connection of IBM G8264 Switch

For 40G connection, both fiber optic connection and copper connection can be built by using different components. A 40GBASE QSFP+ to QSFP+ DAC can provide connection between IBM G8264 and target devices up to 7 meters. With multimode fiber optic cables, distance up to 100 meters (OM3) and 150 meters (OM4) can be reached, when using with 40GBASE-SR4 QSFP+ transceivers. For long distance 40G transmission, 40GBSE-LR QSFP+ transceiver and single-mode fiber optic cable with LC connectors are suggested. Related components for IBM G8264 switch are concluded in the following chart.

Modules Cable & Connector Distance
49Y7884: QSFP+ 40GBASE-SR Transceiver MTP connector, MMF 100 m(OM3)
100 m(OM4)
00D6222: 40GBASE-LR4 QSFP+ Transceiver LC connector, SMF 10 km
BN-QS-QS-CBL-1M: QSFP-to-QSFP cable (1 meter) 1-7 m
BN-QS-QS-CBL-3M: QSFP-to-QSFP cable (3 meter)

To make full used of the switches in data center with great flexibility, both the selection of switch and cabling solutions is very important. IBM G8264 as a switch with great flexibility is an ideal solution for data center upgrading to 40G. The above mentioned modules and cables are all provided by FS.COM, which are IBM G8264 compatible and are fully tested on the IBM G8264 switches. Kindly contact sales@fs.com for more details, if you are interested.


40GBASE-SR4 QSFP+ transceivers is now being widely used for 40G network interconnection in short distance. This is a highly integrated component which has small size and uses four channels to support conversions between optical signals and electrical signals over a high data rate up to 40G. However, another component which can replace this transceiver in network interconnection becomes popular in data center application. It is 40GBASE QSFP+ AOC (active optical cable).

AOC is a kind of direct attached cable (DAC), which is available in 10G, 40G and even 120G. 40GBASE QSFP+ AOC contains a QSFP+ connector on one end and one QSFP+ connector on the other end which are linked by a length of fiber optic cable. There are also fanout versions of 40GBASE QSFP+ AOC with one end connected with a QSFP+ connector and the other end with several SFP+/XFP connectors. It looks like a fiber optic patch cable, but, it has a similar function of optical transceiver, and also can transmission signals with its fiber optic cable. 40G AOC removes the process of two modules, which must be done in a 40G interconnection using 40G SR4 QSFP+ transceiver. It seems that both 40G AOC and 40G transceiver are good solutions for interconnection. However, everything has it’s Pros and Cons. Figure out the one that fits your application is the most reasonable way. The following is to offer comparison between these two components for your references.


Transmission Distance: The first aspect to be considered is the transmission distance of these two components. Currently the 40G transmission is usually used in backbone network. Thus, to assure the transmission quality, distance should be ensured. Both 40GBASE-SR4 QSFP+ and 40GBASE QSFP+ AOC are designed for 40G transmission in short distance. Generally, when the distance is shorter than 100 meters, the two have similar performance. However, when it’s longer than 100 meters, AOC cannot perform as good as transceiver. Currently most 40G AOC provided by the manufacturers are less than 100 meters. However, Fiberstore can provide 40G AOC up to 300 meters.

Reliability: In work state, both of the components should be inserted into a switch or server. And the repeating plug of them are necessary for daily use and maintenance. It is known to us that, these actions might affect the performances of the component. Thus reliability of these components should be considered. The connectors of 40G AOC are factory pre-terminated, while QSFP+ SR4 transceivers are connected by additional MPO connectors and fiber optic cable. Thus, compared with QSFP+ SR4 transceiver, AOC is less affected by the repeating plug during daily use. It has been proved that AOC has better reliability than that of transceivers.

Installation and Maintenance: it has been clear that 40G AOC is much easier during installation, as the connectors have already terminated in factory. Customers just need to plug the two connectors in the switches, then can start working. While, for 40G SR4 QSFP+, additional patch cords with MPO connectors are used to finish the link. If there is a fault in the interconnection, for AOC, you can just replace it with another AOC. However, for interconnection using 40G QSFP+ SR4 transceivers, you have to locate the fault firstly by testing the patch cords and optics.

40GBASE-SR4 QSFP+ transceiver under test

Digital Diagnostic Monitoring (DDM): to achieve the best working state, most modern transceivers are armed with DDM function. With it, the working states and performance of the optics can be visually controlled. No wonder that 40GBASE-SR4 QSFP+ has such function. However, 40G AOCs that are provided by the market now do not have it.

Cost: two main aspects should be considered in selection a product in data center. One is the material cost. The other is the maintenance cost in the daily use. AOC has advantages over transceivers on both aspects. The price for 40G AOC is generally cheaper than 40G QSFP+ SR4. In addition, the interconnections reply on 40G transceivers also need additional fiber optic cables. The latter aspect has been clearly illustrated in the above. AOC can save more in general.

In conclusion, 40GBASE-SR4 QSFP+ can achieve best working status by using DDM and it has better performance when the transmission distance is longer than 100 meters. While 40GBASE QSFP+ AOC is cheaper, easy to manage and test, and it has similar performance as the former does over transmission distance less than 100 meters. For your reference, Fiberstore offer a wide range of both 40GBASE-SR4 QSFP+ and 40GBASE QSFP+ AOC. You can trust all of them cause they are all be tested before they go to the marker. Kindly contact sale@fs.com or visit FS.COM for more detail, if you are interested.

How to Select the Right Fiber Patch Cable for 40G QSFP+ Transceiver?

It is clear that most servers in data center can support Ethernet transmission of 40G and 40G QSFP+ transceivers are considered to be the most economical solution for 40G transmission in data center. However, to make all these devices run normally and effectively, fiber patch cables must be used to connect the fiber optic transceivers which are plugged in Ethernet switches which is shown in the following picture. As the structure of 40G transmission is more complex than ever, the select of patch cords for 40G QSFP+ transceiver becomes more difficult. This article will focus on how to select the proper patch cords for 40G QSFP+ transceivers in details.

switch connection

Let’s get straight to the point. Numerous things need to be taken into consideration for proper selecting the fiber patch cables for 40G QSFP+ transceivers in practical cabling. However, several factors should always be considered: the cable type of the patch cords, the connector attached on the ends of the patch cords, and the ports of the switches that need to be connected.

For the first factor to be considered is cable type. This is because of the transmission characteristic optical signals of the fiber optic. Optical signals performs different over different wavelength. And optical signals with the same wavelength performs totally different when they run through different types of cables.

A question that people might come across can illustrate the above point well. Can a 40GBASE universal QSFP+ transceiver working on wavelength of 850nm be used with OM1 patch cords? Usually, signals with wavelength of 850nm are transmitted over short distance. Thus selecting a multimode fiber patch cords would be more economical. However, OM1 patch cords, which are ususally suggested for 100Mb/s and 1000Mb/s, cannot support 40G transmission and the quality of the 40G transmission is bad. This is because the transmission distance reduced as the data rate raised. For this case, OM3 and OM4—the optimized multimode fiber optic cables for 40G transmission in short distance are suggested. OM3 can support 40G transmission up to 100 meters and OM4 can support 40G transmission up to 150 meters.

The second aspect should be considered is the connector type that attached on the both ends of the patch cords, which is usually decided by the interface of the 40G transceivers. Usually 40G QSFP+ transceivers for short distance are armed with MPO interface and for long transmission distance up to 10 km usually employ LC interface. However, there are several 40G QSFP+ transceivers do not follow this rule, like 40GBASE-PLR4 and 40GBASE-PLRL4. These transceiver with MPO interface can support transmission over long distance. The biggest characteristics of MPO connector is high density which seems perfectly satisfy the requirement of 40G transmission. However, for this kind of connect, the polarity becomes complex. Thus during the selecting of this types of patch cords. The polarity must be considered. For your reference, here offers another article which is informative about MPO polarity—”Understanding Polarity in MPO System”. The following pictures shows the commonly used 40G transceivers with MPO or LC interfaces.

QSFP+ transceivers

The third importance factors is the switch ports which is closely related to the applications. During the practical cabling, two situations are common. One is 40G QSFP+ to 40G QSFP+ cabling and the other is 40G QSFP+ to 10G SFP+ cabling.

For 40G QSFP+ to 40G QSFP+ cabling: for distance up to 100m, the 40GBASE-SR4 QSFP+ transceiver can be used with OM3 fiber patch cable attached with a MPO one each end. For distance up to 150m, the 40GBASE-SR4 QSFP+ transceiver can be used with OM4 fiber patch cable attached with a MPO one each end. For distance up to 10km, the 40GBASE-LR4 QSFP+ transceiver can be used with single-mode fiber with LC connectors. The picture above shows the transmission of 40GBASE-LR4 QSFP+ transceiver with LC connector over single-mode fiber.

For the 40G QSFP+ to 10G SFP+ cabling, fan out patch cable with MTP connector on one end and four LC duplex connectors on the other end is suggested (as shown in picture below).

MTP=8LC patch cords

In conclusion, three main factors must be considered are fiber optic cable type, fiber optic connector type and the switch port. In practical cabling, more should be considered. These three aspects are far from enough. However, Fiberstore can solve your problems with professional one-stop service including the cost-effective and reliable network designing and 40G products. You can contact sales@fs.com for more details.

Three Factors to Consider for Smooth Migration to 40G

10GbE (Gigabit Ethernet) is no longer enough for the increasing need for high speed transmission with applications like Big Data, Cloud and Internet of Things being introduced in a variety of industries. Transmission network migration to 40/100G has already been the industry consensus. As the cost for 100G is far beyond what most companies can afford and the technology for 100G is still not mature, there is still a gap to reach the transmission speed of 100 Gb/s. However, to satisfy the current need for data rate, 40G could be a better and more economic solution. Currently the servers in many data centers are ready to carry the transmission of 40 Gb/s. The core technologies of 40G are gradually mature. In addition, more manufacturers are battling for the 40G market, which drives down the 40G deployment price.

Unlike 1G migrating to 10G, 10G migration to 40G get across a much larger span in terms of not only transmission data rate but also technologies. Thus, the deployment of 40G migration is much more complicated than that of 10G. Three factors should be considered to increase the reliability and manageability for 40G migration. They are fiber optic transceiver, transmission media, and pre-terminated MPO assemblies.

Fiber Optic Transceiver

Fiber optic interconnection is indispensable in today’s telecommunication network. Photoelectric conversion is a necessary part in fiber optic network. The function of fiber optic transceiver is photoelectric conversion, which makes it one of the most commonly used components in the data center. Without it, the data center cannot run normally.

QSFP-40G-LR4 testing on Cisco switch

As for 40G migration, transceivers of two different package forms are commonly used: QSFP+ transceiver (Quad Small Form-factor Pluggable Plus transceiver) and CFP transceiver (C Form-factor Pluggable transceiver). QSFP+transceiver is more popular in 40G application. A single 40G fiber optic transceiver may not be expensive. However, to a medium-sized data center, thousand of optical transceivers might be needed. The total cost on optical transceivers is a large sum of money. The switch market has already been monopolized. Luckily, the transceiver market is not. Third party transceivers that are compatible with a variety types of switches can be found in today’s market. They have the same performances that the original brand transceivers have, but cost less money. Selecting compatible transceivers has become the choice of many data centers. Cost is one aspect that should be considered in 40G optical transceiver selection. Quality is also very important. Not all the third party transceivers are created equal. Selecting the compatible 40G transceivers from a company that assures 100% compatibility and interoperability is necessary. The above picture shows the testing of Cisco compatible QSFP-40G-LR4 transceivers on a Cisco switch to ensure its compatibility and interoperability.

Transmission Media

40G standards of IEEE have already been announced several years ago. To meet various situations, there are standards for different transmission media. Although fiber optic cable is becoming more and more popular, there is still a place for copper cable in data center. Standards for both copper and fiber optic are being used. Commonly used 40G Ethernet media systems include the following:

  • 40GBASE-CR4: 40Gb/s Ethernet over copper cable in short transmission distance.
  • 40GBASE-SR4: 40Gb/s Ethernet over four short-range multimode fiber optic cables.
  • 40GBASE-LR4: 40Gb/s Ethernet over four wavelengths carried by a signal long-distance single mode fiber optic cable.

It comes to the old question: fiber optic cable or copper cable, which should be used in 40G migration? Copper is cheaper. But it can only support 40G transmission limited to several meters. Single mode fiber optic cable supports the longest 40G transmission distance up to 10 km. For multimode fiber optic cables, OM3 and OM4 are suggested to support short distance transmission. The longest distance that OM3 can support for 40G transmission is 100 m. OM4 can support a longest 40G transmission distance of 150 m. The selection of transmission media should depend on the specific applications.

pre-terminated MTP assemblies

MPO Assemblies for 40G

According to the IEEE standards, the 40G multimode Ethernet transmission uses four multimode fiber optic cables. The IEEE 802.3ba standard also specifies multi-fiber push-on (MPO) connectors for standard-length multimode fiber connectivity. Most of the 40G multimode Ethernet transceivers are based on the MPO technology. It is wise to increase fiber optic density by using MPO technology, but a new problem is coming up. As the fiber number increased, the cabling and splicing difficulty in data center increased. Unlike traditional two-strand fiber connections, MPO connectors cannot be field terminated easily. Most of the data centers choose the pre-terminated MPO assemblies (as shown in the above picture) in 40G deployment, which is more reliable and can save more human labor. Before cabling, determine the cabling lengths and customized pre-terminated MPO assemblies with manufacturers would save a lot of time and money.


Selecting a compatible third party transceiver of high quality in 40G transmission would save a lot of money. Combining specific applications and characteristics of 40G transmission media, would help to determine the most economic and reliable 40G deployment plan. Pre-terminated MPO assemblies are necessary for flexible and manageable cabling in 40G deployment. 40G migration is happening now and it will become a milestone in the history of network transmission.