Tag Archives: 40GBASE-LR4

Design Consideration for 40G Ethernet Network

With the speed in the data center now increases from 10G to 40G, different optical technology and cabling are required. But at first we should figure out the design of 40G Ethernet network. There are several key factors that may affect the transition to 40G. This article today will pay special attention to those aspects that influence data center design consideration.

General Data Center Design
The principal goals in data center design are flexibility and scalability, which involve site location, building selection, floor layout, electrical system design, mechanical design and modularity. Furthermore the key to a successful data center facility: one that is sustainable in the long term; the other is to consider it as a receptacle for equipment and operations, as well as an integrated system, in which each component must be considered to be flexible and scalable. Figure 1 shows a typical data center infrastructure design utilizing preterminated optical solutions.

data center design

What Does MPO Connector Means for 40G Data Center?
While speeds have increased to 40G, optical connectivity has remained in a duplex format, whether SC or LC. With the advent of 40G/100G Ethernet, multi-fiber push-on (MPO) connector technology are now used at the electronics interface and further into the data center infrastructure design. MPO technology has displayed proven value in cassette-based data center physical layer installations.

The MPO is defined by TIA-604-5-C, Fiber Optic Connector Intermateability Standard. Type MPO (FOCIS-5) as an array connector that can support up to 72 optical fiber connections in a single connection and ferrule. While the MPO is versatile in the fiber count supported, the 12-fiber MPO is the version widely deployed. Many data center designs today use cassette-based duplex LC connectivity or MPO to duplex LC harnesses at the electronics interface, while 12-fiber MPO-based connectivity is used to connect the trunk cabling to each cassette or harness.

40G Standard Provision
The Habtoor STFA Soil Group (HSSG) has designated 40G to support high-performance computing clusters, blade servers, SANs and network-attached storage. For 40G deployment, the QSFP transceiver will utilize a 12-fiber MPO. Deployment of 40G over multi-mode fiber will be achieved with 4-Tx and 4-Rx fibers from the 12-fiber MPO (see in Figure 2). Each of these four “channels” will transmit 10G for the combined 40G transmission. Single-mode fiber transmission will remain duplex connectivity using course wavelength division multiplexing. The HSSG has also defined the transmission media for 40G to include:

MPO connector

  • 40GBASE-SR4 (parallel optics)

100m on OM3/125m on OM4—10G on four fibers per direction

  • 40GBASE-LR4(cWDM)

10km on single-mode fiber—4x10G 1300nm wavelength region

  • 40GBASE-CR4

7m over copper—4x10G (twinax copper)

  • 40GBASE-FR(Serial)

2km on single-mode—4x10G 1550nm

As noted above, the QSFP+ module is specified for use with different standard. The 40GBASE-SR4 is terminated with the MPO connector. For example, Cisco QSFP-40G-SR4 QSFP+ transceiver enables high-bandwidth 40G optical links over 12-fiber parallel fiber terminated with MPO/MTP multifiber female connectors.

For 12-fiber MPO cassette-based optical systems already installed, 40G migration is as simple as removing the existing cassette from the patch panel housings at the equipment and cross connects and replacing the cassette with an MPO adapter panel. Next, an appropriate 12-fiber MPO jumper would be used to cross-connect the trunk cabling as well as interconnect into the QSFP. Though not widely available currently, future preterminated system trunks may utilize 24-fiber MPO connections, both on the trunks and on the cassette. In this case, 40G deployment would require an interconnect harness terminated with two 12-fiber MPO connectors at the QSFP end, and one 24-fiber MPO at the trunk end. This would provide the needed interface with the 24-fiber MPO-based trunk and the 40G QSFP. A 24-fiber MPO jumper would be needed at the system cross connects to ensure polarity was maintained and that skew was within requirements.

The data center infrastructure must be reliable, manageable, flexible and scalable no matter who you are asking for requirements of data center design. It is the responsibility of the network designers to insure best compatibility of data center. As migrating to 40G, we have 40G QSFP and cables within MPO connectivity. Fiberstore supplies a variety of 40G QSFP modules and cables for you to choose from. Besides QSFP-40G-SR4, QSFP-40G-SR4-S and Cisco QSFP-40G-CSR4 are also available. If you are interested in our products, please contact us directly.

The 40G QSFP transceiver Comparison

Data center regularly went through great migration from 1G, 10G to 40G, 100G over the past few decade. Since IEEE 802.3ba standard defined the 40G Ethernet on June 17, 2010. The newest widely adopted optical transceivers is the QSFP+ that offers aggregated optical speeds of 40G. There are many variants for QSFP+ small from factor including LR4 (10km single-mode), IR4 (2km single-mode) or ESR4 and SR4 for short haul multi-mode. So what are they and what is the difference between them? The following passage will provide a satisfying answer to you.

QSFP optical transceivers have four separate 10G channels to simultaneously operating for supplying 40GbE network and sum up the capacity into a single channel. The following tables shows QSFP40G portfolio, of which 40GBASE-SR4, 40GBASE-LR4 and 40GBASE-ER4 are the most commonly used 40G physical layers.


  • 40GBASE-SR4

40GBASE-SR4 (short range) is a port type for multi-mode fiber and uses 850nm lasers. It uses four lanes of multi-mode fiber delivering serialized data at a rate of 10.3125 Gbit/s per lane. 40GBASE-SR4 has a reach of 100m on OM3 and 150m on OM4. There is a longer range variant 40GBASE-ESR4 with a reach of 300m on OM3 and 400m on OM4. This extended reach is equivalent to the reach of 10GBASE-SR. Take JG325A (see in Figure 2) as an example, it is HP compatible 40GBASE-SR4 QSFP+ transceiver. It primarily enables high-bandwidth 40G optical links terminated with MPO multi-fiber connectors and can also be used in a 4x10G module for interoperability with 10GBASE-SR interfaces.


  • 40GBASE-ER4

40GBASE-ER4 (extended range) is a port type for single-mode fiber being defined in P802.3bm and uses 1300nm lasers. It uses four wavelengths delivering serialized data at a rate of 10.3125 Gbit/s per wavelength.

  • 40GBASE-LR4

40GBASE-LR4 (long range) is a port type for single-mode fiber and uses 1300nm lasers. It uses four wavelengths delivering serialized data at a rate of 10.3125 Gbit/s per wavelength. Take FTL4C1QE1C as an example, it is Finisar FTL4C1QE1C  (see in Figure 3) compatible 40GBASE-LR4 QSFP+ transceiver supporting link lengths of 10km at a wavelength of 1310nm.

Finisar FTL4C1QE1C

Comparison of These Three 40GBASE Standards
Through the above definitions of each type of 40G physical layers, you may have a further understanding of them. Now, we are comparing them one by one. 40GBASE-SR4 is for multi-mode fiber while 40GBASE-LR4 and 40GBASE-ER4 is a port type for single-mode fiber. The multi-mode solutions require special MPO fiber ribbons (multi-strand optical cables) to transport the 4 different 10G optical connections. Single-mode solutions use only two strands of fiber and combine the 4 channels using inexpensive CWDM technology. This gives a tremendous advantage, simplifying the connectivity to standard LC optical connectors and thus reducing costs further.

In addition, 40GBASE-LR4 QSFP+ transceivers are most commonly deployed between data-center or IXP sites with single mode fiber. 40GBASE-SR4 QSFP+ transceivers are used in data centers to interconnect two Ethernet switches with 12 lane ribbon OM3/OM4 cables. And from the above figure, we can know that they support different transmission distance in different wavelengths and with different connectors.

To sum up, 40GBASE-SR4, 40GBASE-LR4 and 40GBASE-ER4 are distinguished with each other in several different features—wavelength, connector, transmission distance, etc. Fiberstore offers a wide variety of high-density and low-power 40GBASE QSFP+ transceiver modules. They are the best-selling products of our company for its large stocks, competitive price and high quality. In addition, there are also a promotion for MTP cables. For more information, please contact us directly.


40 Gigabit Ethernet Solution

40 Gigabit Ethernet is a standard that enables the transfer of Ethernet frames at speeds of up to 40 gigabits per second (Gbps), allowing 40 Gigabit Ethernet-enabled equipment to handle traffic at the aggregation and core layers. It satisfies the greater demands for faster data transmission and higher bandwidths. Thus, the business case for 40 Gigabit Ethernet is becoming inescapably compelling although 10 Gigabit Ethernet is still making its way into data center. A right and cost-effective solution for 40 Gigabit Ethernet is very necessary for all users who want to migrate to 40G.

40 Gigabit Ethernet Solution

The picture above is the summary about 40 Gigabit Ethernet, explaining significantly that cables and transceivers are the basis of the whole solution. And actually, they are also the main cost of the item. Next some types of 40 Gigabit Ethernet cables and 40g qsfp transceiver will be introduced in details.

40 Gigabit Ethernet Cables

The cable applied in 40 Gigabit Ethernet can be optical fiber or copper cable. The copper cable for 40 Gigabit Ethernet is designed for short reach, up to at least 7 m. As to optical cable, there are two types: singlemode cable and multimode cable. The transmission distance of multimode cable for 40 Gigabit Ethernet can be up to 150 m, which is much shorter than the transmission distance of singlemode cable (It can be up to 10 km). Generally, the common used types are OM3 and OM4 multimode cables in that its reach supports a wider range of deployment configurations compared to copper solutions, and the cost is lower compared to singlemode solutions.

What is more, the MPO cable (Multi-Fiber Push On)/MTP (Multi-fiber Termination Push-on) cable is considered the best solution for 40GbE. It can connect the multimode transceivers to support the multifiber parallel optics channels. For 40 Gigabit Ethernet, we can use 8 fibers MPO/MTP harness cables or 12 fibers MPO/MTP trunk cables. The former is to directly connect a QSFP port to other 4 SFP+ ports. The latter is to directly connect one QSFP port to another QSFP port. Here is a picture to help you know it clearly.

MTP Cable

40G QSFP Transceiver

According to different standard form factors, 40g qsfp transceivers can be divided into different types, such as CFP transceiver, CXP transceiver and QSFP transceiver, ect.

CFP transceiver, which has 12 transmit and 12 receive 10-Gbps lanes, can support one 100 Gigabit Ethernet port, or up to three 40 Gigabit Ethernet ports. This module is used for 40GBASE-SR4, 40GBASE-LR4. The former is based on 850nm technology and supports transmission over at least 100m OM3 parallel fibers and at least 150m OM4 parallel fibers, while the latter is based on 1310nm , coarse wave division multiplexing (CWDM) technology and supports transmission over at least 10km on singlemode fiber.

CXP transceiver also has 12 transmit and 12 receive 10-Gbps lanes as well as CFP transceiver, supporting one 100 Gigabit Ethernet port or up to three 40G qsfp ports. Compared with CFP transceiver, the size of it is much smaller. And it is mainly designed for the high-density requirements of the data center, serving the needs of multimode optics and copper.

QSFP transceiver provides four transmit and four receive lanes to support 40 Gigabit Ethernet applications for multimode fiber and copper today. The size of it is the same with CXP transceiver. It is mainly designed to support Serial Attached SCSI, 40G Ethernet, PCIe, 20G/40G Infiniband, and other communications standards.

Fiberstore 40 Gigabit Ethernet Solution

Fiberstore can offer customers 40 Gigabit Ethernet connectivity options for data center networking, enterprise core aggregation, and service provider transport applications. Since the products are all in good quality and low price, it may be the best choice for you to deploy the network.