Establishing 40G Links With OM3 and OM4

To meet the needs of Internet users, the business users in particular, who require faster speeds, greater scalability, and higher levels of network performance and reliability, data centers have experienced infrastructure transformation, from 10 Gbps to 40 Gbps and then to 100 Gbps, or even higher, never-ceasing. Actually, during this bandwidth migration, 40G provides an efficient use of hardware and a more logical upgrade path to 100G. And in establishing 40G links, fiber optic cabling, (eg OM3 and OM4) has become an integral part of the overall system design.

Background Information

The Institute of Electrical and Electronics Engineers (IEEE) 802.3ba 40/100G Ethernet Standard was ratified in June 2010 to support the fast-growing demands for bandwidth in data centers. The standard provides specific guidance for 40G/100G transmission with multi-mode fibers (MMFs) and single-mode fibers (SMFs). OM3 and OM4 are the only approved multi-mode fibers included in this standard.

Using OM3 and OM4 for 40G Links

The IEEE 802.3ba only specified OM3 for a maximum reach of 100 m in its original draft. Later, efforts have been made to win the approval to include OM4 in the standard. As a matter of fact, OM4 can achieve the greater reach of 150 m compared with OM3. In 40 GbE transmission which uses MMFs, an optic module interface is used for the simultaneous data transmission and data reception. Like JNP-QSFP-40G-LX4, this Juniper Networks proprietary 40G-LX4 transceiver listed on FS.COM realizes 100 m transmission on OM3, and 150 m transmission on OM4. Besides, JNP-QSFP-40G-LX4 can also run over SMF for 2 km link lengths.

, transmission media :SMF ,MMF

Evaluating OM3 and OM4 Performance

When evaluating the performance of the OM3 and OM4 cabling infrastructure for 40GbE transmissions, three aspects should be taken into consideration: bandwidth, channel connector insertion loss (CIL) and skew.

  • Bandwidth

In the standard, the bandwidth is ensured by meeting the effective modal bandwidth (EMB) specification. The EMB measurement techniques utilized nowadays are effective modal bandwidth calculate (EMBc) which combines the properties of both the source and fiber. The EMBc process predicts source-fiber performance by integrating the fundamental properties of light sources with the MMF’s modal structure which has been measured using a standardized differential modal delay (DMD) measurement. Within 40G links using OM3 and OM4 fibers measured by the EMBc technique, the optical infrastructure shall meet the performance criteria set forth by IEEE for bandwidth.

  • Channel Insertion Loss (CIL)

CIL is a critical performance parameter in current data center cabling deployments. It refers to the total insertion losses that happen when the signal moves along a fiber optic cable. Within a system channel, CIL impacts the ability to operate over the maximum distance at a given data rate. With total connector loss increasing, the maximum distance at that given data rate decreases. The 40/100G standard specifies the OM3 to a 100m distance with a maximum channel loss of 1.9dB, while OM4 is specified to a 150m distance with a maximum channel loss of 1.5dB.

  • Skew

Skew is classified as the difference between the arrival times of simultaneously launched light signals traveling through parallel cable lanes. When evaluating OM3 and OM4 performance for 40applications, selecting one that meets the 0.75ns skew requirement can ensure the performance.

Establishing 40G Links With OM3 and OM4

40G is deployed using eight of the twelve fibers in a MPO connector. Four of these eight fibers are used to transmit while the other four to receive. Each Tx/Rx is operating at 10G. The 40GBASE-SR4 (eg. QFX-QSFP-40G-SR4) interface is as follows: 4 x 10G on four fibers per direction.

40GBASE-SR optical lane: 4 x 10G on four fibers per direction

OM3 and OM4 for 40G connectivity provide a significant value proposition when compared to SMF, as MMF utilizes low cost 850nm transceivers for serial and parallel transmissions. OM3 and OM4 ensure today’s bandwidth needs.

Conclusion

To continue to accommodate the bandwidth needs, OM3 and OM4 are the ideal solution for 40G links in the data center. FS.COM offers broad selections of OM3 and OM4 fibers of high quality, as well as fiber optic transceivers working over OM3 and OM4, such as JNP-QSFP-40G-LX4 and QFX-QSFP-40G-SR4 mentioned above. You can visit FS.COM for more information about OM3 and OM4, MMF.

40G Needed for Data Center Networks

Driven by growing bandwidth and network performance demand, data center network infrastructure is witnessing a transformation. As technology evolves, standards are completed to define data rates such as 40 Gigabit Ethernet (GbE) to meet such demands of high networking speed and performance. 40GbE addresses physical layer specifications for communication across backplanes, copper cabling, single-mode fiber(SMF), and multi-mode fiber (MMF).

The Need for Higher Speed – 40G

1G and 10G data rates are not adequate to meet the future needs of high-bandwidth applications. The requirement for higher data rates is being driven by many factors. Switching and routing, virtualization, convergence and high-performance computing environments are examples of where these higher network speeds will be required within the data center environment. Additionally, Internet exchanges and service provider peering points and high-bandwidth applications, such as video-on-demand driving the need for a migration from 10G to 40G interfaces.

40G Physical Layer Alternatives

40GbE standards already exist for SMF, MPO based MMF, as well as copper cables. Listed below are three physical layer solutions for 40GbE.

Single-mode Fiber

Due to its long reach and superior transmission performance, SMF is specified for carrying 40Gbps data up to a distance as long as 10km (40GBASE-LR4). The physical layer electronics and optics consist of four channels, each carrying 10Gbps data with different wavelengths. When there is no need to consider budget or the link distances are long, SMF is the preferred option for 40GbE in data center networks.

Multi-mode Fiber

MMF with parallel optics MPO interface is the most popular medium for 40GbE today (40GBASE-SR4). Take F5-UPG-QSFP+ for example, Fiberstore compatible F5 Networks F5-UPG-QSFP+ (figure shown below) is a 40GBASE-SR4 QSFP+ transceiver with MPO connectors. It supports link lengths of 100m and 150m, respectively, on OM3 and OM4 MMFs at a wavelength of 850nm in a data center network. (OM3 and OM4 fibers were selected as the only MMFs for 40G consideration.)

Copper Twinax

For short reach channels up to a length of 7m, 40GBASE-CR4 standard specifies use of twinax copper cable assembly. One typical application of this kind of copper cable is in 40G QSFP+ direct attach cable (DAC). For instance, Fiberstore compatible Brocade 40G-QSFP-C-0101 is the QSFP+ to QSFP+ passive copper cable assembly for very short distances.

40G Transceivers

40G transceivers were developed along several standard form factors. The C Form-Factor Pluggable (CFP) transceiver features 12 transmit and 12 receive 10-Gbps lanes to support one 100 Gigabit Ethernet port, or up to three 40 Gigabit Ethernet ports. Its larger size is suitable for the needs of single-mode optics and can easily serve multi-mode optics or copper as well. The CXP transceiver form factor also provides 12 lanes in each direction, but is much smaller than the CFP and serves the needs of multi-mode optics and copper. The Quad Small-Form-Factor Pluggable (QSFP) is similar in size to the CXP and provides four transmit and four receive lanes to support 40 Gigabit Ethernet applications
for multi-mode fiber and copper today.

Conclusion

40GbE supports high-speed switching, routing, and application functions in data centers. It provides optimized performance in meeting data center requirements. As a professional fiber optic products supplier and manufacturer, Fiberstore offers various 40GbE products, like 40G transceivers, and 40G cabling available both in fiber and copper. You can visit Fiberstore for more information about 40GbE solutions.

40G QSFP+ Module for High-speed Connection Networks

Are you still worrying about your network speed? Actually, there is no need to worry about this. The dramatic growth in bandwidth requirements has led to the increasing worldwide use of higher-performance optical products. Like 40G QSFP module, they support 40G network and allow data rates of 4×10 Gbit/s to be enjoyed by users in better-performance data transmission. This article introduces 40G QSFP+ module in details, which include 40G QSFP+ module and 40G QSFP+ cables.

40G QSFP+ Module Introduction

40G QSFP+ module is a compact, hot-pluggable transceiver used for data communications applications. QSFP+ transceivers are designed to carry Serial Attached SCSI, 40G Ethernet, QDR (40G) and FDR (56G) Infiniband, and other communications standards. QSFP+ modules increase the port-density by 3x-4x compared to SFP+ modules.

Main Features of 40G QSFP Module
  • Support for 40GBASE Ethernet;
  • Flexibility of interface choice;
  • Interfaces available in various form factors;
  • Certified and tested on QSFP 40G ports for superior performance, quality, and reliability;
40G QSFP Module Overview

40G QSFP module are high-density interfaces addressing deployment of high-performance computing in data center clouds. 40GBASE QSFP+ modules in this article are mainly introduced in two different flavors: 40G LR4 QSFP+ transceiver, and 40G SR4 QSFP+ transceiver.

40G LR4 Transceiver—40GBASE-LR4 (“long range”) is a port type for single-mode fiber and uses 1300nm lasers. 40G LR4 QSFP+ transceiver supports 40GBASE Ethernet rate. The 40 Gigabit Ethernet signal is carried over four wavelengths. Multiplexing and demultiplexing of the four wavelengths are managed within the device.

40G SR4 QSFP+ Transceiver—40GBASE-SR4 (“short range”) is a port type for multi-mode fiber and uses 850nm lasers. Take HP 720187-B21 transceiver for example, Fiberstore compatible HP 720187-B21 enables high-bandwidth 40G optical links and support link lengths of 100m and 150m respectively, on OM3 and OM4 multimode fibers at a wavelength of 850nm.

40G QSFP+ Cable Details

Just like 10GbE optics, there are also direct attach cables(DAC) available for 40GbE modules when short distance (within the same rack) is needed. A variety of short-reach copper options are made available to enable 40GbE connection networks.

Direct Attach Copper Cable Reaches for 40GbE

Direct attach copper cables are designed in either active or passive versions. Both are widely used for 40G QSFP+ module solutions. For example, Juniper JNP-QSFP-DAC-7MA runs over active copper cable for very short distances. And Fiberstore compatible Juniper JNP-QSFP-DAC-7MA offers a very cost-effective way to establish a 40gigabit link between QSFP ports of Juniper switches within racks and across adjacent racks.

There are also active optical cables available for 40GbE, like FCBG410QB1C10. This transceiver runs over active optical cable for 40GBASE Ethernet.

Summary

40GbE ports are capable of running in a 4x 10GbE mode, allowing for easy 10GbE/40GbE mixed media deployments. Fiberstore offers a broad selection of 40G QSFP modules for high-speed network connections, including the above-mentioned HP 720187-B21 and Juniper JNP-QSFP-DAC-7MA. For more information about 40G QSFP+ transceivers and 40G QSFP+ cables, you can visit Fiberstore.

40GBASE-SR4 QSFP+ Transceiver Overview

The 40G QSFP+ transceiver is a hot-swappable transceiver module which integrates 4 independent 10Gbit/s data lanes in each direction to provide 40Gbps aggregate bandwidth. 40GBASE QSFP+ transceiver provides a wide variety of high-density 40 Gigabit Ethernet connectivity options for data center and computing networks. 40G QSFP+ transceivers have various types like QSFP-40G-CSR4, QSFP-40G-PLR4, 40GBASE SR4 transceiver and so on. The following passages will mainly introduce the 40GBASE-SR4 QSFP+ transceiver.

Specifications of 40GBASE-SR4 QSFP+ Transceiver

The 40GBASE SR4 QSFP+ transceiver modules support link lengths of 100m and 150m respectively on laser-optimized OM3 and OM4 multimode fibers. It primarily enables high-bandwidth 40G optical links over 12-fiber parallel fiber terminated with MPO/MTP multifiber connectors. And also, it can be used in a 4 x 10G mode for interoperability with 10GBASE-SR interfaces up to 100m and 150m on OM3 and OM4 fibers respectively. The worry-free 4 x 10G mode operation is enabled by the optimization of the transmit and receive optical characteristics of the QSFP-40G-SR4 to prevent receiver overload or unnecessary triggering of alarm thresholds on the 10GBASE-SR receiver, at the same time being fully interoperable with all standard 40GBASE-SR4 interfaces. The 4 x 10G connectivity is achieved by using an external 12-fiber parallel to 2-fiber duplex breakout cable, which connects the 40GBASE-SR4 module to four 10GBASE-SR optical interfaces. Below is a picture of 40GBASE-SR4 QSFP+ transceiver.

40GBASE-SR4 QSFP+ module

From the above statement, it can be seen that 40GBASE-SR4 QSFP+ transceiver uses MPO (Multi-fiber Push-On) connector to support optical links. Why use MPO connectors rather than other connectors? Please keep reading the below passage and you will get an answer.

MPO Connector Used in 40GBASE-SR4 QSFP+ Transceiver

With higher speed transmission mode, 40GbE drives the data center to run at a high-density and cost-effective style. Thus, parallel optics technology is considered to be a perfect solution for transmission due to its support of 10G, 40G and 100G transmission. The IEEE 802.3ba 40G Ethernet standard offers 40G transmission a direction by using laser-optimized OM3 and OM4 multimode fibers. Parallel optical channels with multi-fiber multimode optical fibers of the OM3 and OM4 are utilized for implementing 40G Ethernet. The small diameter of the optical fibers has no problems with the lines laying, but the ports must accommodate four or even ten times the number of connectors. So the large number of connectors cannot be covered with conventional individual connectors any more. Under this situation, 802.3ba standard incorporated the MPO multi-fiber connector for 40GBASE-SR4 because MPO connector provides a smooth transition to higher Ethernet speeds with minimum disruption and without wholesale replacement of existing cabling and connectivity components.

In fact, MPO connectors have either 12-fiber or 24-fiber array. For 40GBASE-SR4 QSFP+ transceiver, a MPO connector with 12 fibers is used. 10G is sent along each channel/fiber strand in a send and receive direction and only 8 of the 12 fibers are required and provide 40G parallel transmission as shown in below figure.

40GBASE-SR4 QSFP+ transceiver

After looking through the above illustration, have you got a brief understanding of the 40GBASE-SR4 QSFP+ transceiver? Fiberstore, a leading and professional 40gbase sr4 qsfp+ manufacturers, offers high quality 40G qsfp+ transceiver including 40Gbase SR4 transceiver, 40GBASE-LR4 transceiver, Cisco QSFP-40G-SR4, etc. If you are looking for a 40G transceiver. Fiberstore would be a primary choice. For more information, please visit www.fs.com.