Three Cabling Solutions for 40G Network

Network technology has been developed rapidly and many data centers are utilizing 40G network to satisfy their needs for high density cabling and high speed data transmission. When it comes to 40G network cabling solutions, MPO fiber optic cable assemblies are most used by data center managers. This article is going to introduce three cabling solutions for 40G network—cabling with no conversion component, cabling with conversion module and cabling with conversion harness.

Cabling With No Conversion Component

For cabling with no conversion component solution, in fact, it is a Base-12 MTP connectivity solution. The 12-fiber MTP trunk cables are deployed in the whole 40G connectivity. But in this cabling solution, four fibers are not used. Apart from this, there will be additional cost associated with the purchase of additional fibers. Though this solution does notuse 33% of the installed fiber and may require more cable raceway congestion, it does have the advantage of simplicity and lowest link attenuation.

Cabling With Conversion Module

With the use of conversion module MPO patch panel, the unused fibers can be converted into usable fiber links. For every two 12-fiber MTP connectors in the backbone cable, we can create three 8-fiber links. Using Base-12 connectivity and Base-8 connectivity together realizes 100% fiber utilization. When reusing existing deployed MTP cabling, great value will be gained if using conversion module to use all previously deployed fibers, and we can eliminate the cost of having to deploy additional cabling.

canling with conversion module to convert two 12-fiber links into three 8-fiber links

Cabling With Conversion Harness

The cabling with conversion harness solution uses standard MPO patch panel and 2×3 MPO conversion harness. It can achieve full fiber utilization. Although it seems attractive, it involves considerable cabling challenges. For instance, if you only need two 40G connections to the equipment, what do you do with the third 8-fiber MTP connection? Or what if the 40G ports are in different chassis blades or completely different chassis switches? The result will be long assemblies, which will be difficult to manage in an organized way. For this reason, this kind of solution is expected to be the least desirable and so the least deployed method.

cabling with conversion harness to convert two 12-fiber links into three 8-fiber links

Which One to Choose?

If you are installing new cabling, then you can consider cabling with no conversion component solution, assuming that the cable raceway is not a concern. If you are using previously installed MTP trunks, cabling with conversion module solution is recommended which can realize 100% fiber utilization while maintaining any port to any port patching. The cabling with conversion harness solution is typically deployed only in specific applications, such as at the ToR switch, where 40G ports are in a close cluster and patching between blades in a chassis switch is not required.

Conclusion

It is not difficult to find that each type of cabling solution has their own advantages and disadvantages. As for which on to choose, it all depends on your specific network deployment environment and requirements. After reading the content above, I hope you can have a better understanding of these three cabling solutions for 40G network and choose a suitable cabling solution for your network deployment.

Can 40GBASE-LR4 Be Used for 4x10G?

We know that 40GBASE-SR4 QSFP+ transceiver can be used for 4x10G SFP+ connections, because it offers 4 independent transmit and receive channels, each capable of 10G operation for an aggregate data rate of 40G over 100 meters of OM3 MMF or 150 meters of OM4 MMF. However, for 40GBASE-LR4 QSFP+ transceiver, it is commonly utilized over long transmission distance of SMF in 40G network applications. Can 40GBASE-LR4 be used for 4x10G? The answer depends and this article will focus on this question.

40GBASE-LR4 CWDM QSFP+ Transceiver Cannot Be Used for 4x10G

The 40GBASE-LR4 CWDM QSFP+ transceiver, such as QSFP-40GE-LR4, is compliant to 40GBASE-LR4 of the IEEE P802.3ba standard. It contains a duplex LC connector for the optical interface. The maximum transmission distance of the transceiver is 10km over SMF. In the transmit side, the transceiver converts 4 inputs channels of 10G electrical data to 4 CWDM optical signals by a driven 4-wavelength distributed feedback (DFB) laser array, and then multiplexes them into a single channel for 40G optical transmission, propagating out of the transmitter module from the SMF. Reversely, the receiver side accepts the 40G CWDM optical signals input, and demultiplexes it into 4 individual 10G channels with different wavelengths. Each wavelength channel is collected by a discrete photo diode and output as electric data after being amplified by a transimpedance amplifier (TIA). Therefore, 40GBASE-LR4 CWDM QSFP+ transceiver cannot be used for 4x10G. It cannot be split into 4x10G, because it uses 4 wavelengths on a pair of single-mode fiber with LC duplex connector, and does not allow itself to split into 4 pairs without substantial complexity to split out the wavelengths.

Working Principle of 40GBASE-LR4 CWDM QSFP+ Transceiver

40GBASE-LR4 PSM QSFP+ Transceiver Can Be Used for 4x10G

The 40GBASE-LR4 PSM QSFP+ transceiver is a parallel single-mode optical transceiver with an MTP/MPO fiber ribbon connector. It also offers 4 independent transmit and receive channels, each capable of 10G operation for an aggregate data rate of 40G on 10km of single-mode fiber. The transmitter side accepts electrical input signals compatible with common mode logic (CML) levels. All input data signals are differential and internally terminated. The receiver side converts parallel optical input signals via a photo detector array into parallel electrical output signals. That’s to say, the parallel optical signals are transmitted parallelly through 8 single mode fibers. As a result, 40GBASE-LR4 PSM QSFP+ transceiver can be used for 4x10G, because it uses parallel (ribbon) fiber with MTP/MPO connector, which allows the creation of 4 fiber pairs.

Working Principle of 40GBASE-LR4 PSM QSFP+ Transceiver

Note: From an optical transceiver module structure viewpoint, PSM uses a single uncooled CW laser which splits its output power into four integrated silicon modulators. Therefore, it allows for splitting into 4x10G (single-mode).

Conclusion

In a world, the answer of question “Can 40GBASE-LR4 be used for 4x10G?” depends. The 40GBASE-LR4 CWDM QSFP+ transceiver cannot be split into 4x10G, while for 40GBASE-LR4 PSM QSFP+ transceiver, it cab be used for 4x10G. To put it simply, 40G QSFP+ transceiver which is with MTP/MPO interface can be used for 4x10G connections, otherwise, it can only support 40G link. The 40G QSFP+ transceivers mentioned above can be found in FS.COM, if you want to know more details, please visit our site.

Originally published at http://www.china-cable-suppliers.com/can-40gbase-lr4-used-4x10g.html

Practical Knowledge About Base-8 and Base-12

MTP system is now popular among data center managers, because it can provide high-density cabling while saving time. Base-8 and Base-12 are two most used cabling solutions and both them have their own advantages. For example, Base-8 can realize 100% cable utilization while Base-12 can provide higher fiber count for cabling. As both Base-8 and Base-12 play an important role on the basis of MTP system, some network designers may ask “will one cabling solution fit all applications? Or can I deploy Base-8 and Base-12 together to combine their advantages?”. This article aims to share the practical knowledge about Base-8 and Base-12, and you will find the answer after reading this article.

No One Cabling Solution Can Fit All Applications

We know that Base-12 makes use of fiber optical links based on increments of 12 fibers and 12-fiber MTP fiber optic connector is common used. However, there is a problem when using Base-12 cabling solution—four fibers for transmit and four fibers for receive, leaving four fibers unused per connection. While Base-8 can be a more cost-effective option for end-to-end MPO to MPO channels and architectures. Deploying Base-8 connectivity in duplex architectures for 10GBASE-SR and 25GBASE-SR will save 4% to 5% for data center managers, but if you are running groups of 6-ports, Base-8 may result in a significant cost increase. Generally speaking, no one cabling solution can fit all applications. In fact, in some cases, Base-12 may still be more cost-effective.

Deploy Base-8 and Base-12 Together: Yes or No?

Since Base-8 or Base-12 are not universal solutions, it seems that the best choice for data center managers is to deploy Base-8 and Base-12 together in the same data centers. Can we do that? The answer of the question depends. If directly mix the components and plug a Base-8 MPO MTP cable into a 12-fiber module, then the answer is “No”. Base-8 components and Base-12 components are not designed to be plugged directly into each other. Generally, Base-12 MTP trunk cable has unpinned (female) MTP connectors on both ends and demands the use of pinned (male) breakout modules. While the Base-8 MTP trunk cable is manufactured with pinned connectors on both ends. So plugging a Base-8 trunk cable into a Base-12 breakout module will definitely not work. However, Base-8 and Base-12 can be used in the same data center, but they should be maintained independently. As they are not interchangeable, some care is needed when managing the data center physical layer infrastructure, to ensure Base-8 and Base-12 components are not mixed within the same link.

Deploy Base-8 and Base-12 Together Yes or No

Conclusion

From the content above, we can get that there is no one cabling solution fitting all network applications. To make full use of the advantages of Base-8 and Base-12, they can be used in different applications according to different requirements. For the most commonly 10G to 40G migration, Base-8 would be a strong consideration over Base-12. Although Base-8 and Base-12 are not interchangeable, but they can be used in the same data center as long as the links are maintained separately.

MTP Connectivity — Low-loss Multifiber Connectivity

It is not difficult to understand that MTP connectivity is widely applied in 40G and 100G network applications because it is a multifiber connectivity, which can meet the demand for high-density cabling. As a matter of fact, there is another key advantage of MTP connectivity, that is low-loss. With the length and type of the fiber cable, number of connectors and splices all contributing to the link loss, there is no doubt that insertion loss is inevitable during the cabling process. Therefore, cabling solution with low-loss will be preferred by data center managers, who are now regarding optical insertion loss budgets as one of the top concerns. But what contributes to low-loss in MTP connectivity? This post will show you the answer.

Low-loss Connector

Typical MPO/MTP fiber connector, which is used for 40 and 100 GbE deployments, has insertion loss values that range from 0.3 dB to 0.5 dB. In addition, MPO/MTP connector is structured with MT ferrule which has low insertion loss and can provide accurate fiber alignment. Take 12 fiber MPO connector and 24 fiber MPO connector for example, with low-loss ferrules, the insertion loss of both two type of connectors can be rated at 0.35 dB maximum. Reading this, you may ask shouldn’t the result be that higher fiber count will lead to higher insertion loss? The answer is no. Because when using proper polishing techniques, 24-fiber MPO/MTP terminations can meet the same performance levels as 12-fiber MPO/MTP assemblies.

Low-loss Cable

We know that OM3 and OM4 fibers used in MTP connectivity utilize 850 nm source, and IEEE 40GBASE-SR4 and 100GBASE-SR10 standards for 40 and 100 GbE over multimode fiber have more stringent loss requirements for these two types of fibers, which lowers the overall channel loss. As shown in the following table, as speeds have increased from 1 Gb/s to 40 and 100 Gb/s, maximum channel distance and loss has decreased significantly. For OM3 fiber cabling, the 40 and 100 GbE standards allows for a channel distance of 100 meters with a maximum channel loss of 1.9 dB, including a maximum connector loss of 1.5 dB; for OM4 fiber cabling, the distance is increased to 150 meters but with a maximum channel loss of 1.5 dB, including a maximum connector loss of 1.0 dB.

channel loss of OM3 and OM4 fibers

Note: Current TIA and ISO standards require a minimum of OM3 fiber, while TIA recommends the use of OM4 due to its longer transmission capabilities. In fact, the 100GBASE-SR4 standard that uses eight fibers (four for transmitting and four for receiving) at 25 Gb/s is anticipated to be supported by OM4 fiber to 100 meters, but to only 70 meters using OM3.

Conclusion

In today’s large virtualized server environments with high speed 40 and 100 gigabit Ethernet (GbE) backbone switch-to-switch deployments for networking and storage area networks (SANs), staying within the loss budget is essential for ensuring that optical data signals can be properly transmitted from one switch to another without high bit error rates and performance degradation. MTP connectivity, based on low-loss MPO/MTP connector, OM3 and OM4 fibers, is able to reduce the insertion loss to a minimum, which makes this low-loss multifiber connectivity take its place on the market. FS.COM provides high-quality MTP assemblies, such as MTP/MPO fanout cable, MTP MPO trunk cable, MTP cassette and so on. If you want to know more details, please visit our site.

Originally published at http://www.china-cable-suppliers.com/mtp-connectivity-low-loss-multifiber-connectivity.html

Focus on MTP-link

Characterized by providing ideal plug-and-play solutions for structure cabling, pre-terminated cabling system has gained great popularity among data center manager in recent years, and it is considered as the norm for data center network deployment. In this cabling system, optical link is accomplished by pre-terminated cabling assemblies, such as MTP/MPO trunk cable, MTP/MPO to LC breakout cable, MTP/MPO cassette and MTP/MPO fiber optic patch panel. It not difficult to find that all these MTP/MPO fiber optic cable assemblies are based on the structure of MTP/MPO connector. And two types of MTP/MPO connectors—12 fiber MTP connector and 24 fiber MTP connector are commonly used for 40G and 100G transmission. This article will focus on MTP-link and share share some opinions about MTP-link performance with you.

12-fiber MTP connector vs. 24-fiber MTP connector

About Space Utilization

High-density cabling makes the available space in data centers always precious. MTP/MPO fiber optic cable assemblies used in MTP-link that contributes to promoting space utilization are reputably appraised by data center managers. With massive cables being adopted in the data centers to carry out data transmission, MTP-link offers cabling solutions with much higher density and flexibility for data center upgrades.

About Insertion Loss

As well know that insertion loss is inevitable during the cabling. Generally, lower overall optical loss allows more margin for the network to operate, or in the case for some users, offers the option of more connections for patching locations. Therefore, components characterized by low insertion loss will be preferred. For both 12-fiber and 24-fiber MTP/MPO connector performance, the industry standard product rating is 0.5 dB maximum. And using low-loss ferrules, both 12 fiber MPO connector and 24 fiber MPO connector can be rated at 0.35 dB maximum. What’s more, there is no need to worry about higher fiber count will lead to higher insertion loss, because when using proper polishing techniques, 24-fiber MPO/MTP terminations can meet the same performance levels as 12-fiber MPO/MTP assemblies.

About Fiber Utilization

Both 12-fiber MPO cable and 24-fiber MPO cable can be used in 100G applications. When used in 4x25G solutions, 4 fibers of 12-fiber MPO cable will remain unused. As for 24-fiber MPO cable, it can be converted into three 8-fiber 100G channels that run over one cable, with all 24 fibers used to support data transmission. Maybe you feel confused about this, let me take an example. If you need to support twelve 100G channels with the 4x25G standard, by using 12-fiber MPO cable, you will need to install 12 connectors, or 144 fibers total, with 33% of the fiber wasted; while by using 24-fiber MPO cable supporting the same 12 channels, only 4 cables would be required, using 96 fibers total, at 100% fiber utilization.

About Network Performance

It is self-evident that MTP-link offers consistent high levels of network performance for improved network integrity, because the assemblies are factory terminated and the transmission testing is performed by the manufacturer before shipment. This will reduce the likelihood of many problems that may occur with field terminations. Also, testing and troubleshooting time can be greatly saved.

Conclusion

By using MTP components, MTP-link can provide fast installation, high density and high performance cabling for data centers. As 40G and 100G Ethernet is now a trend and hotspot for data center cabling system, MTP-link is a great option for data center managers and the network deployment will benefit a lot from this cabling solution. I hope after reading this article, you can have an in-depth understanding of MTP-link.

What Is Pre-terminated Cabling System in Essence?

As 40G and 100G have been applied in data centers to satisfy the demands of massive data transmission, high-density cabling system has become a common phenomenon. Solutions characterized by quick installation are preferred since they can save time and money. Pre-terminated cabling system has come into data center managers’ sight in recent years, because it can provide quick, plug-and-play network deployment for structure cabling. Then, what is pre-terminated cabling system in essence? And what we can expect from this cabling alternative? The information about pre-terminated cabling system will be fully covered in this article.

Overview of Pre-terminated Cabling System

Pre-terminated cabling system refers to factory manufactured cables and modular components with connectors already attached. Usually those cables and modular components have been tested, qualified and are ready to plug and play in network deployment. In addition, they are available in both fiber and copper cabling. Pre-terminated cabling system simplifies the installation of network devices by providing high-density and plug-and-play solution. Pre-terminated assemblies come in various forms, such as MTP trunk cable, MTP fanout cable or MTP breakout cable, MTP fiber optic cassette and pre-terminated cable bundles with protective pulling grips installed over the connectors at one end (shown as the following figure).

pre-terminated assemblies

Advantages of Pre-terminated Cabling System

Pre-terminated cabling system can bring a raft of advantages to cable installers and end-users.

Time Saving

The high speed deployment offered by pre-terminated cabling system is an equally important feature which helps to save time in various ways. The quick plug-in connections of network devices allow fiber and copper links to be installed in significantly less time than traditional field-terminated links. In addition, since the assemblies are factory terminated, the transmission testing is performed by the manufacturer before shipment. This greatly saves testing and troubleshooting time. Also, pre-terminated assemblies are factory terminated which reduce many of the problems that may occur with field terminations.

Space Saving

For data centers, the available space for high-density cabling is always precious. Components that contributes to promoting space utilization will gain popularity among data center managers. With massive cables being adopted in the data centers to carry out data transmission, pre-terminated assemblies offer cabling with much higher density and flexibility for data center upgrades.

Labor Saving

With pre-terminated assemblies, you don’t need as many on-site engineers pulling cables in and terminating them. As the pre-terminated links have been pre-tested, this vastly mitigates the need for troubleshooting and retesting.

Cooling Advantage

It is necessary to pay attention to heating and cooling issues in high-density cabling environment. Pre-terminated cabling system allows much more flexibility in configuration for installers working in compact space. It is also able to optimize airflow by using pre-terminated assemblies such as MTP trunk cable and MPO cassette, in conjunction with high density frames.

Applications of Pre-terminated Cabling System

Pre-terminated cabling system is commonly used in two fields: data center and open office. In response to the accelerated network capacity and application processing demands, data centers are expanding dramatically both in number and size. Pre-terminated cabling system provides an ideal plug-and-play solution for links between switches, servers, patch panels, and zone distribution areas in the data center. The open office also benefits from the pre-terminated cabling system which can be quickly reconfigured to match the moves, adds and changes. Pre-terminated cabling system offers unsurpassed advantages over conventional field installed system, which partially explains why the use of factory pre-terminated assemblies continues to grow, especially for data centers.

Conclusion

With several advantages of time saving, space saving, labor saving and cooling, pre-terminated cabling system provides an increasingly popular way of delivering a project in a more timely and cost effective manner. If your data center or network application needs speed and testing simplified installation, pre-termination cabling system is an ideal choice.

Why Short Distance MTP-based Connectivity Utilizes OM3 or OM4 Fibers?

As today’s network needs to support more devices and advanced applications than ever before, the amount of data transmitted at the enterprise business level is rapidly climbing. For many data centers, 10G network no long satisfies the need of high speed data transmission. In 2010, the IEEE ratified the 40G ad 100G standard. Then how to realize smooth migration path from 10G to 40G and 100G has become the most concern for data center managers. After some comparison, many data center managers turn to MTP-based connectivity since it can provide fast installation, high density and high performance cabling for data centers. It is not difficult to find that both MTP/MPO trunk cable and MTP/MPO breakout cable (shown as the figure below) used for short distance connectivity utilize OM3 or OM4 fibers. Why short distance MTP-based connectivity utilizes OM3 or OM4 fibers? This article will show you the reason.

MTP MPO trunk cable and MTP MPO breakout cable

Bandwidth

OM3 and OM4 fibers are the only multimode fibers included in the 40/100G standard. Multimode fibers utilize parallel optical transmission instead of serial transmission due to the 850 nm VCSEL (vertical cavity surface emitting laser) modulation limits. And OM3 and OM4 fibers have a minimum 2000 MHz∙km and 4700 MHz∙km effective modal bandwidth (EMB). The minimum EMBc (Effective Modal Bandwidth calculate) method measures the actual fiber bandwidth performance, recognizing the fact that overall system bandwidth is a function of both the bandwidth properties of the fiber and also the particle characteristics of individual laser sources, and this is the most significant factor in determining link performance. In addition, the IEEE model is the industry reference point for calculating the maximum achievable Ethernet link distance and sets out the minimum requirements of components in an optical link. Therefore, knowing the exact minimum bandwidth performance of OM3 and OM4 fibers is a prerequisite to understand the ultimate limitation of MTP-based connectivity, which can ensure the optical infrastructure deployed in the data center will meet the performance criteria set forth by IEEE for bandwidth.

Insertion Loss

No matter what kind of cabling system you are going to deploy, insertion loss is inevitable and it is an essential performance parameter of the network deployment. It is important to note that the total connectivity loss within a cabling system has an effect on the network performance over the maximum link distance at a given data transmission rate. It is not difficult to understand that the higher the total connectivity loss, the shorter the maximum link distance. As a result, the insertion loss specifications of components used for connectivity should be evaluated at first when designing data center cabling infrastructures. The 40G standard specifies that with link distance up to 100 meters, the maximum channel loss of OM3 fiber is 1.9 dB, which includes a 1.5 dB total connectivity loss budget; while for OM4 fiber, it is specified that with link distance up to 150 meters, the maximum channel loss is 1.5 dB, which includes a 1.0 dB total connectivity loss budget. And the maximum attenuation of fiber optic cable at 850 nm is 3.5 dB/km. With low-loss OM3 and OM4 fibers, maximum flexibility can be achieved with the ability to utilize MTP connector in the optical link.

Conclusion

With 850nm EMB of 2000 MHz∙km and 4700 MHz∙km, OM3 and OM4 fibers can provide the bandwidth which is needed in MTP-based connectivity for 40G network. Besides, low-loss within cabling system is another characteristic of OM3 and OM4 fibers, which can ensure the high performance of the network deployment. Therefore, utilizing OM3 and OM4 fibers makes short distance MTP-based connectivity an ideal solution for migration from 10G to 40G in data centers.

Orginally published at: http://www.china-cable-suppliers.com/why-short-distance-mtp-based-connectivity-utilizes-om3-or-om4-fibers.html