Tag Archives: 40G

Active Copper Cable—Economical Interconnection Solution

In today’s data center, direct attached cable (DAC) is widely used for interconnection. With 40G migration, DAC becomes more popular, because they can support the high data rate and complete the interconnection in short time effectively. Currently, there are three types of DACs: passive copper cable, active copper cable and active optical cable (AOC). However, different DAC have different performances and prices. Passive or active? Copper or optical? Which DAC is the one you need?

In data center, the battle between performance, transmission distance and cost has never ended. This is also true to the selection of DAC for 40G data center interconnection. To find a cost-effective 40G DAC solution for data center interconnection with reliability and stability, this article will provide you the solution by several rounds of battle between the three types of DAC.

active copper cable connection

Battle Over Transmission Distance

The first round of battle is transmission distance which is always the first factors to be considered during the selection of DAC. This is because it is closely related to the transmission distance. There is no wonder that optical cable can transmit signals over longer distance than that of the copper cable. When the data rate required for interconnection is less than 5 Gbps, the passive copper cable is usually used for interconnection in data center. However, they can only support 40G transmission over really short distance. Optical cable is used to overcome the challenge of the distance. Supported with connectors that are embedded with electronics/optics, 40G active optical cable can support 40G transmission up to 100 meters. Active copper cable can support 40G transmission over copper cable up to 15 meters with QSFP+ connector embedded with electronics. In the battle over transmission distance, optical active cable wins without doubt.

Battle Over Power Consumption

The connectors attached with AOC and active copper cable are the main reason why the two cables can support 40G transmission over longer distance than that of passive copper cable. AOC which can support the longest 40G transmission distance is with the highest power consumption—more than 2W. The power consumption for active copper cable is only 440mW. However, passive copper cable requires no power during the transmission. In this battle, passive copper cable wins and AOC lost its advantages and is in the third place.

Battle Over Cooling

Cooling is closely related to data center reliability and life of use. The DAC in the data center can also affect the cooling of data center. The cable size and power consumption will directly influence the cooling efficiency of the data center. The thinner the cable is, the better dispersion devices in data center would have. Among the three types of DACs, optical cable is the thinnest among the three types of DAC. Active copper is also thinner than passive cooper cable. Active copper is also thinner than passive cooper cable. As mentioned, AOC has the highest power consumption and active copper cable has a lower power consumption, while passive copper cable requires no power. In this round of battle, it’s hard to tell which one wins. It depends on the practical and specific situations in the data center.

Battle Over Cost

It is clear that copper is much cheaper than optical cable. AOC, with connectors embedded with electronics and/or optics is the most expensive one. AOC is strongly recommended if cost is not a problem. It has the best transmission performance. However, for many data centers, it’s hard to have an ideal situation like this. Cost sometime can determine the final decision of the choice in data center cabling. Most of the components in data center are expensive and require careful maintenance. Passive copper cable is much cheaper than AOC. However, it cannot support 40G transmission in most cases in data center. Active copper cable is less expensive than AOC and can support longer transmission than passive copper cable seems to be a good choice.

Active Copper Cable—Economical Interconnection Solution


After several rounds of battle, the price and performances of the three DACs are clear. What to be considered next is the practical application. After several rounds of battle, the price and performances of the three DACs are clear. What to be considered next is the practical application. In most data center, most server to server connections require 2-5 meters, while rack to rack connections are required to be connected by 8-12 meters cables. For 40G transmission, the application of passive copper cable is limited because it only supports really short transmission distance. AOC has the best transmission performance. However, it costs most in both material and daily use. It’s expensive and needs more power. And in daily maintenance, they need careful management, because the optical cables are fragile. If cost is not a problem, then AOC is suggested for 40G transmission.

What to be considered next is the practical application. In most data center, most server to server connections require 2-5 meters, while rack to rack connections are required to be connected by 8-12 meters cables. Due to the Active copper cable, which is less expensive and can support 40G transmission up to 15 meters with low power consumption, can satisfy the regular interconnection requirement for distance and cooling in most data center. For the cost, you also don’t need to worry about, as it is much cheaper than AOC and it is stronger than AOC during cabling and daily maintenance. If you are looking for an economical solution to upgrade your data center to 40G, then active copper cable won’t let you down. The following chart can illustrate the advantages of active copper cable clearly.

DAC Type 40G Transmission Distance Power Consumption Price
Passive Copper Cable 5m Reach 0W Inexpensive
Active Copper Cable 15m Reach 440mW Moderately Priced
Active Optical Cable 100M+ Reach 2W+ Expensive

Fiberstore provides a full range of 40G active copper cables of high quality. All the connectors and cable lengths can be customized according to your applications. You contact sales@fs.com for more details.

Cabling With High Density Push-Pull Tab Patch Cords

It is inevitable to plug fiber patch cables from the patch panels, switches or cassettes in today’s data center cabling. However, this simple movement becomes harder and harder nowadays. Why? Both the data rate of every optical fiber and the fiber counts being used are increased to support high data rate up to 40/100G or more. Thus, the cabling density increased largely with the deployment of 40/100G Ethernet network. Finger access to every patch cable that is loaded on the patch panel, switches or cassettes becomes difficult. Especially for these patch cables in the middle of the space.

For fiber patch cords attached with connectors like LC, things become more complex. Because this type of connectors are usually locked in the port with a latch on the connector body. If you want to plug out a patch cord with LC connectors, you should firstly unlock the connector from the port by clicking the latch with is with small size (shown in the following picture). Usually an external tool is used to unplug the specific connector in a high density cabling. It seems a problem doesn’t matter much in the whole cabling. However, during practical cabling, network engineer could be headache about this annoying problem. To find an easy and elegant way to solve this finger access problem, a new type of patch cords was invented, which is designed for high density cabling and is known as push-pull tab patch cords.

finger access for high-density cabling

What Is High Density Push-pull Tab Fiber Patch cable?

Compare with the traditional patch cords. This new type patch cord is attached with a connector with a push-pull tab, which can perfectly solve the fiber access problem in high density cabling. Except the additional tab for pushing and pull, these connectors don’t change much from the traditional ones that attached to patch cords. But this little change makes a great difference. The following is offering you the details about this novel product.

High density push-pull tab fiber patch cords are usually attached with LC or MPO connectors, as these two types of connector are currently the most popular in high density cabling like 40G, 100G, 120G or more. The following pictures shows the details of these two types of connectors with push-pull tab.

The one in the left of the following picture is an LC connector attached on push-pull tab patch cable. It’s of standard LC size. When the tab is pulled the LC connector would be unlocked from the port easily, cause the tab is linked to the latch of the LC connector. Once the LC connector is unlocked, the patch cords would be smoothly plugged out from the port and other patch cords around it by pulling the tab slightly. As for MPO connector with push-pull tab shown in the following picture on the right side. Finger access becomes easier. The tab can greatly simplify the use of MPO connectivity when manual access to the release slider and rear portion of the connector is restricted. In this way, easy insertion and extraction of MPO patch cords can be achieved.

push-pull tab patch cords connectors

Get More From Push-pull Tab Patch Cable

Is finger access the only advantage of push-pull tab patch cords. Definitely NO. The following illustrating will surely make you exciting about push-pull tab patch cable.

  • Flexibility and adjustability: it has been proved that push-pull tab can increase the cabling density by 30% to 50%, which can satisfy the future high density cabling requirements for 120G or more.
  • Reliability: To reach the specific connector you want, you might loosen or remove other connectors around it, which can highly increase the reliability of the network.
  • Cost-save and time-save: it is clear that with push-pull tab patch cords, cabling becomes easy and elegant with higher ROI.
Fiberstore Push-Pull Tab Fiber Patch Cable Solutions

If you are looking for a simple and easy high density patch cabling solution, push-pull tab patch cords provided by Fiberstore can satisfy your requirements. The following chart is the most common applications of push-pull tab patch cords for your references.

Application Patch Cords Cable Type Connectors on Both Ends
10G to 10G Cabling Duplex LC Push-pull Tab Patch Cord OM3/OM4/Single-mode Duplex LC Duplex LC
40G to 40G Cabling 12-fiber MPO Push-pull Tab Trunk Cable OM3/OM4/Single-mode MPO (male/female) MPO (male/female)
40G to 10G Cabling 12-fiber MPO to 8 LC Push-pull Tab Break out Cable OM3/OM4/Single-mode MPO (male/female) 4 Duplex LC
100G to 100G Cabling 24-fiber MPO Push-pull Tab Trunk Cable OM3/OM4/Single-mode MPO (male/female) MPO (male/female)

For more details and customized solution of push-pull tab patch cords, you can always access Fiberstore by FS.COM or emailing us at sales@fs.com

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.