QSFP-40GE-LR4—An Ideal Solution for 40G Long Distance Transmission

It is reported that the data of deploying 40G Ethernet network is still increasing from 4% in 2015 to 7% in next year of 2017, although the deployment performs not so easy as that of 10G Ethernet network. For the sake of higher bandwidth and faster data transmission rate, it seems that the deployment of 40G Ethernet network has been much more necessary than ever before to accommodate the rapid development of network. Are you also interested in deploying 40G Ethernet network that will make better performance for your system? In this paper, it will mainly introduce one of the most widely used QSFP+ transceiver, QSFP-40GE-LR4 for 40G long distance transmission, which plays an important role in deploying 40G smooth migration.

QSFP-40GE-LR4 Transceiver Overview

As one of the most widely used QSFP+ transceiver, QSFP-40GE-LR4 transceiver offers an individual 40GbE links that provides better performance with higher bandwidth in the transmission process, instead of SFP transceivers with multiple 10GbE links. The following figure shows an example of QSFP-40GE-LR4 transceiver for your reference.

It is easy to learn that the letter “L” in its name indicates long distance, the letter “R” means the type of interface with 64B/66B encoding and “4” stands for four channels. That’s to say, QSFP-40GE-LR4 transceiver is able to support 40G Ethernet network for long distance transmission, at lengths up to 10 kilometers, which consists of a standard pair of single-mode fiber and duplex LC connectors. Meanwhile, it has four channels in each direction to transmit and receive signals, each of which has a 10 Gbps data rate to achieve a total 40 Gbps data rate.

Working Principle of QSFP-40GE-LR4 Transceiver

In QSFP-40GE-LR4 transceiver working process, it will firstly convert four inputs channels of 10Gbps electrical signals to four CWDM optical signals, and then multiplexes these four signals into a single channel as a 40Gbps data. Secondly, the data will be propagated out of the transmitter module through single mode fiber and accepted by receiver module. Thirdly, the 40Gbps data will be de-multiplexed into four individual 10Gbps optical signals with different wavelength, and each signal will be transmitted through an individual channel. Finally, these 10Gbps optical signals will be collected by a discrete photo diode, amplified by a TIA, and then outputted as electrical signals.

Compared to 10G SFP transceiver, it is much more complicated in the working process of QSFP-40GE-LR4 transceiver that uses with CWDM technology. To help you better understand its working principle, here offers the whole working process through the following figure that illustrates how QSFP-40GE-LR4 transceivers finish 40G transmission.

Guide for Installing QSFP-40GE-LR4 Transceiver

As an indispensable device for deploying 40G Ethernet network, QSFP-40GE-LR4 transceiver can be installed without powering off the system, which provides much convenience and flexibility. However, there are still some points should be paid attention to in the installation process. Here lists the step-by-step procedure of installing QSFP-40GE-LR4 transceiver that may be helpful for you to achieve a smooth 40G migration.

• Get QSFP-40GE-LR4 transceiver from the antistatic container.
• Before installing the transceiver, please remove the dust cover from its connector. Meanwhile, if there is a protective pad covering the card-edge connector, please also remove it.
• Put the antistatic container, dust cover and protective pad away, so that they can be stored cleanly, and found easily if the transceiver need to be uninstalled.
• Check and remove the rubber dust cover from the port where the transceiver will be installed.
• Hold the transceiver by its sides, and then insert it into the port on the switch.
• Lightly slide the transceiver into the port until it is dropped into place.
• Push up the handle of the transceiver to secure the transceiver in the switch.

Notice: Please pay attention that QSFP-40GE-LR4 transceiver contains Class 1M lasers and it may cause invisible laser radiation. Hence, when the laser connections are unplugged, you should not stare at it which really does harm to your eyes.

Conclusion

Since 40G Ethernet network has become an irreversible trend to achieve higher bandwidth and ensure better performance, there is no doubt that it will finally take the place of 10G Ethernet network. As one of the most commonly used transceiver for 40G migration, QSFP-40GE-LR4 transceiver would be an ideal solution for 40G long distance transmission.

QSFP-40GE-LR4 and QSFP-40G-SR4 Modules Comparison

Have you ever complained about your slow network speed when you are working in a hurry, watching the most wonderful and interesting part of a movie or doing something else that are delayed by your bad network? Do you want to upgrade your system for higher data transmission speed? Have you ever heard about 40G QSFP+ module which is able to solve your problem? In this post, it will introduce two commonly used types of QSFP+ modules used to upgrade your network from 10G Ethernet to 40G Ethernet, to some extent, avoiding time delay.

40G QSFP+ Modules Overview

Nowadays, there are several solutions designed for deploying 40G Ethernet network, such as, 4 x 10GE Breakout cable, 40G QSFP+ modules or 40G CFP modules. Both of these solutions can achieve the 40GbE with higher capacity. As one of the most commonly used solutions among them, 40G QSFP+ module is a good choice to make the 40G migration. Do you have a good knowledge of 40G QSFP+ modules in the fiber market? At present, there are many variants of 40G QSFP+ modules published to support different applications, defined by IEEE 802.3ba. For instance, QSFP-40GE-LR4, QSFP-40G-PLR4, QSFP-40G-SR4, QSFP-40G-CSR4, etc.

Differences Between QSFP-40GE-LR4 and QSFP-40G-SR4

Among the variants of 40G QSFP+ modules, QSFP-40GE-LR4 and QSFP-40G-SR4 are the most widely applied modules that are designed for different aims. Their features are much different from each other, varying from fiber type to transmission distance. The following will basically analyze the differences between these two modules that may be useful for you to select a proper 40G QSFP+ module.

• Different Fiber Type

As for QSFP-40GE-LR4 module, it has four WDM lanes to transmit and receive signal, which generally works with single-mode fiber. With the advantage of single-mode fiber, it can transmit 40G signals with a long distance. As for QSFP-40G-SR4 module, it has four lanes, which enables high-bandwidth 40G optical links over 12-fiber multimode fiber, operating on a parallel mode. Although it can’t support long distance transmission like QSFP-40GE-LR4 module, it has the ability to carry many kinds of optical signals in 40G Ethernet network.

• Different Connector

As for the connector, QSFP-40GE-LR4 module always uses duplex LC connectors to connect single-mode fiber, while QSFP-40G-SR4 module is often terminated with MPO/MTP connector used for linking 12-fiber multimode fiber. What should pay attention to is that each kind of connector is easy to be smudged, which may cause a negative effect on the transceiver performance. Hence, no matter which module you choose to deploy 40G Ethernet network, please use a dust plug to protect the connector if the QSFP+ module is not working, so that the connector can be stay in a clean condition.

• Different Wavelengths

There is no doubt that the light wavelengths are also different used for transmitting signals. As for the former one, it generally uses signals with four different wavelengths, 1271 nm, 1291 nm, 1311 nm and 1331 nm to achieve 40G long distance data transmission. However, the latter one uses the same wavelengths for four lanes: 4 x 850 nm, supporting 40G short data transmission.

• Different Transmission Distance

It is easy to learn that the letter “L” in QSFP-40GE-LR4 refers to the word “long”, while the letter “S” in QSFP-40G-SR4 stands for “short”. Then how far these two QSFP+ modules can transmit 40G signals? What’s the difference? As for the former one, by using Coarse Wavelength Division Multiplexing technology, it transmit 40G signals through single-mode fiber with four separated or combined 10G SFP+ modules on the other end, with great reach of up to 10 kilometers. However, the latter one can only transmit 40G signals at lengths up to 100 meters on OM3. If it uses OM4 to support the 40G Ethernet network, it can transmit longer, 150 meters.

Conclusion

Have you got any useful information from the post for choosing a suitable QSFP+ module? As above mentioned, QSFP-40GE-LR4 designed with special features is most suitable for 40G long distance transmission, such as, between data-center or IXP sites. If you just need to deploy 40G Ethernet network for short distance, QSFP-40G-SR4 must be an ideal choice with lower price.