FAQs About OM5 Fiber Optic Cable

Data centers everywhere are moving quickly to manage ever-increasing bandwidth demands. And the emergence of cloud computing has acted as catalyst for driving even faster adopting of new network technology and higher bandwidth. Speeds as high as 40G and 100G Ethernet have already become mainstream in data centers, and the industry is working collaboratively on next-generation Ethernet development, such as 200G and 400G Ethernet. In this high speed migration, multimode fiber (MMF) plays an important role. As everyone knows, OM1/OM2/OM3/OM4 are commonly used multimode fibers in networking field, especially OM3 and OM4 are proven to be the future-proofing MMF. And now, a new types of MMF fiber medium—OM5, specified in ANSI/TIA-492AAAE and published in June 2016, is introduced. OM5 is being presented as a potential new option for data centers that require greater link distance and higher speeds, however, is it really a good solutions for data centers? This post will deal with this question from some FAQs about OM5.

Q: Does OM5 Offer a Longer Transmission Distance than OM4?

A: Actually, for all current and future multimode IEEE applications including 40GBase-SR4, 100GBase-SR10, 200GBase-SR4, and 400Gbase-SR16, the maximum allowable reach is the same for OM5 as OM4. According to a recently done application testing with 40G-SWDM4 transceivers, it shows that 40G-SWDM4 could reach 400 meters over OM4 cable, while over OM5 cable, the module can achieve link length up to 500 meters. Besides, if a data center is using non-IEEE-compliant 100G-SWDM4 transceivers, it proven that OM5 can support 150-meter reach—only 50 meters more than OM4. In addition, for most data centers, when transmission distance over 100 meters, IT managers will choose single-mode fiber.

Q: Does OM5 Costs Less?

A: As the matter of fact, OM5 cabling will costs about 50% more than OM4. Besides, with the considerably declined costs of single-mode transceivers over the past 12-18 month due to silicon photonics technologies and large hyperscale data centers buying in large volumes, more and more users will be pone to choose single-mode transceiver modules. For example, 100GBase-PSM4 using single-mode MTP trunk cable that can support 500-meter reach is only $750.

Q: Is OM5 Really Required for Higher Speeds?

A: All of the IEEE standards in next-generation 100/200/400G Ethernet will work either with SMF and MMF, but in most situations, these next-generation speeds will require single-mode fiber, since IEEE always strives to develop future standards that work with the primary installed base of cabling infrastructure, so customers can easily upgrade to new speeds. Besides, none of these current active IEEE standards addressing next-generation speeds will use SWDM technology.

Q: Will OM5 Create Higher Density from Switch Port?

A: As we all know, it is common in data center using 40GBase-SR4 to increase port density by breaking out 40G to 10G with MTP breakout module or MTP breakout cable. This is also a benefit of new 100GBaes-SR4 modules, which use OM4 cabling. However, if data center manager decides to use 100G SWDM4 modules with OM5 cabling, they cannot breakout into 25Gb/s channels, which will become a real issue as the 25Gb/s ecosystem fully develops and we begin to see more 25G to the server.

Summary

According to the questions we have discussed above, it is apparent that OM5 is not suitable for large data centers. As far as I’m concerned, for current high-speed network applications, OM3 and OM4 is still the most recommended multimode fibers.

Can We Use Base-8 and Base-12 Together?

Although 10 Gigabit Ethernet is still marketing its way into the data centers, the need for faster data transfer rates is relentless, which means the migration to 40 Gigabit Ethernet is becoming inescapably compelling. For 40G Ethernet network, there are mainly two connectivity methods, one is Base-8, and the other is Base-12. Base-12 connectivity has had its place in the data center, while Base-8 is a new connectivity that could gain widespread acceptance in the next few years. With these two methods existing in 40G Ethernet network, there comes problems: Which one is more suitable for 40G network, or can we both use these two methods in 40G network? Read this articles, and you will get the detailed answers.

Base-12 Dominates the Market

Base-2 connectivity is the most commonly used one in the past, but as the data center grew to thousands of fiber ports engaged, stringing two-fiber patch cords across all corners of the data center will result in an unmanageable, and unreliable mess. So Base-12 connectivity is introduced. It is designed to develop a modular, high density, structured cabling system which could be deployed in data centers quickly, while also maximizing port densities within the rack space. In this connectivity method, all the fiber optic cables are based on an increment of 12 fiber, like 12-fiber or 24-fiber MTP trunk cable.

Base-8 Shines the Light

Base-12 connectivity is common in data center, but here comes a problem when installed it in a parallel system. For example, if we need to use 40GBase-SR4 optics implemented in a 12-fiber infrastructure, four fibers for transmit, and four fibers for receive, leaving four fibers unused per connection, this will lead to a significant and costly loss in fiber network utilization. But Base-8 can be a more cost-effective option for end-to-end MPO to MPO channels and architectures. With 8-fiber infrastructure, the 40GBase-SR4 module will use all the 8 fibers. Base-8 connectivity makes use of fiber links in increment of 8 versus 12. The 12-fiber trunk cables are replaced with trunk cables in increment of 8: 8-fiber, 16-fiber, or 24-fiber trunk cables, etc.

Can We Use Base-8 and Base-12 Together?

Although using Base-8 connectivity could decrease fiber consuming in supporting 40G data rates, in fact, in many cases, Base-8 connectivity isn’t a universal solution, and Base-12 may still be more cost-effective. So is it possible to have both Base-8 and Base-12 connectivity in the same data center? The answer could be “Yes” or “No”.

Base-8 and Base-12 Fiber Links Cannot Be Mixed and Matched

It is never possible to directly mix the components of Base-8 and Base-12 connectivity, or plug a Base-8 trunk into a 12-fiber module. Because a Base-12 trunk cable normally has unpinned MTP connector on both ends, and requires the use of pinned 12-fiber breakout modules, while a Base-8 trunk cable is manufactured with pinned MTP connectors at both ends (pinned and unpinned MTP connectors are shown below). So if we plug a Base-8 trunk into a 12-fiber breakout module, just like trying to mate two pinned connectors together, this connection will definitely not work, and vice verse.

Base-8 and Base-12 Can be Maintained in the Same Data Center Separately

It is possible to deploy both Base-8 and Base-12 connectivity within the same data center, just as long as the links are separate. Since Base-8 and Base-12 components are not interchangeable, during managing the data center physical layer infrastructure, we should do careful management and labeling practice to ensure we will not mix or mismatch them.

Conclusion

Base-12 connectivity has dominated the 40G network market for years, while the Base-8 connectivity is an additional option in the network designer’s tool kit to ensure that data centers have the most cost-effective, future-proof network available. When using Base-8 and Base-12 in network, make sure that you need to carefully manage and label them, and that the components in Base-8 and Base-12 won’t be mixed.

How to Achieve High-Density and Easy Cable Management?

Increasing demand for data to support streaming media and the increasing usage of mobile broadband communications has resulted in dramatic advances in networking, such as 40/100G Ethernet solutions, which forces data center administrators to face new challenges, maintaining high availability, reducing costs, seeking out high efficiencies and planning for future growth. But when we pursue these goals to maximize density, capacity and performance, cable management could get out of control. High-density fiber connectivity products are the key to make high density a reality without sacrificing streamlined, cost-efficient cable management. The following text will introduce some high-density fiber connectivity components that make up a data center, and the features that can ensure easy cable management along the way.

High-Density Fiber Patch Cable

For standard fiber patch cable, which offers a small overall diameter can improve cable management by installing in dense patch cord trays that take up less space. It also provides better airflow to maintain consistent operating temperatures, reducing the likelihood of failure or downtime. But as cabling density increases, finger access to each patch cable become difficult. To solve this issue, high-density patch cords which deploy a flexible push-pull tab as shown below come into being. These tabs can help increase cabling density and maintain reliability, preventing you from accidentally loosening surrounding connectors as you access the patch cord you need.

High-Density Trunk Cable

High-density trunks allow tighter trunk cable bends for slack storage and routing. When you can find high-density trunks that offer smaller/tighter transitions, less space is consumed and installation will be easier. Besides, when a cable with a smaller overall diameter is used, cable pulling and cable management are improved. MPO or MTP trunk cable as shown below is commonly used trunk types.

High-Density Patch Panel

Crucial for organizing a fiber network, the high-density patch panel provides a centralized location to manage network connections. Not only does it provide physical security for sensitive network connections, it also minimize network downtime by allowing easy access during routine maintenance. It is an ideal solution for installation with space constraints, which is available in flat and angled designs as shown in the image below, with 48 ports in one rack spaces and 72 ports in two rack spaces. The angled design increases rack density, managing high-density applications in one-fourth the area needed for conventional cable management systems.

High-Density Fiber Enclosure

High-density fiber enclosure increases fiber density by up to 50 percent within the same rack space for additional interconnect or cross-connect patching. It is ideal for data center and enterprise applications where network expansion is a priority, now and in the future, and this scalable solution allows you to increase port density in racks to meet expanding network demands. Fiber optic enclosure often comes in two versions: wall mount fiber enclosure and rack mount fiber enclosure as shown below. Typically, wall mount enclosure can be installed directly on wall for fiber cabling, while rack mount enclosure usually has a industry standard 19 inch wide rack unit design and can be installed on a rack for fiber cabling. For higher fiber count, the rack mount enclosure could be 2/4/6/12 rack unit or more.

Summary

Existing and emerging network technologies are driving the need for increased data rates and fiber use in the data center. High-density optical connectivity solutions are essential to address these trends and to facilitate the efficiency of cable management. The products we introduced above are common in a high-density data center. You can choose the right one according to your requirement.

Choosing the Proper Polarity Method for MTP System

Whether in local area network (LAN) campus or data center backbones, we are in the process of migrating to higher-density cabling in order to meet system bandwidth needs and provide the highest broadband network connectivity density. Many network designers are turning to MTP trunk cable for today’s duplex fiber transmission and to provide an easy migration path for future data rates that will use parallel optics such as 40/100G Ethernet. To ensure reliable MTP system performance as well as support ease of installation, maintenance and reconfiguration, choosing the proper polarity method is very important. In this post, we are going to introduce three MTP polarity method for your reference.

What Is Polarity?

Polarity is the term used in the TIA-568 standards to explain how fiber (wire) to make sure each transmitter is connected to a receiver on the other end of a multi-fiber cable. To be specific, as we all know, optical fiber links typically require two fibers to make a complete circuit. Optical transceivers have a transmit side and receive side, and typically deploy a duplex fiber connector as the interface. In any installation, it is important to ensure that the optical transmitter at one end is connected to the optical receiver at the other. This matching of the transmit signal (Tx) to the receive equipment (Rx) at both ends of the fiber optic link is referred to as polarity.

Structure of MTP Multi-fiber Connector

To better understand each polarity method, it is important to make it clear for the MTP connector structure.

Each MTP connector has a key on one side of the connector body. When the key sits on top, this is referred to as the key up position, on the contrary, when the key sits on bottom, we call it key down position. Each of the fiber holes in the connector is numbered in sequence from left to right, and we call these fiber holes as positions, or P1, P2, etc. Besides, there is a white dot as shown below on the connector body to designate the position 1 side of the connector when it is plugged in. Generally, MTP multi-fiber connector is pin and socket connector—requiring a male side and a female side (male side has pins, while female side has no pins) as shown below. Cassette and hydra cable assemblies are typically manufactured with a male connector, while trunk cable assemblies typically support a female connector.

Three Polarity Methods for MTP System

Defined by TIA/EIA-568-B.1-7, there are three polarity methods for MTP system—method A, method B and method C. These methods define installation and polarity management practices, and provide guidance in the deployment of these types of MTP fiber links. Once a method is chosen, these practices must be put into place to insure proper signaling throughout the installation.

Method A: In method, it requires two type A cassettes with key-up to key-down adapters, a straight-through key-up to key-down MTP trunk cables as well as two patch cables. This method, shown below maintains registration of Fiber 1 throughout the optical circuit. Fiber 1 in the near end cassette mates to Fiber 1 in the trunk cable assembly, which mates to Fiber 1 in the remote cassette. The fiber circuit is completed by utilizing one “A-to-A” patch cord at the beginning and “A-to-B” patch cord to insure proper transceiver orientation.

Pros: It provides the simplest deployment, works for single-mode and multimode channels, and easily supports network extensions.

Cons: Requires pre-configured “A-to-A” patch cables, or field configuration of same.

Method B: In type B polarity method, method B cassette requires key-up to key-up adapters to link reversed cable or MTP trunk cable type B. The fiber circuit is completed by utilizing straight “A-to-B” patch cords at the beginning and end of the link, and all of the array connectors are mated key-up to key-up. This type of array mating results in an inversion, meaning that Fiber one is mated with Fiber twelve, Fiber two is mated with Fiber eleven, etc. To ensure proper transceiver operation with this configuration, one of the cassette needs to be physically inverted internally, so Fiber twelve is mated with Fiber one at the end of the link.

Pros: It requires single source for components and “A-to-B” patch cords only. Besides, it is a standard which provides migration path to parallel optics.

Cons: This key-up to key-up method requires a more in-depth planning stage in order to properly manage the polarity of the links, and to identify where the actual inversions need to occur. Moreover, it only support multimode fiber.

Type C: The method C shown below, with the key-up to key-down adapter in the cassette, looks like the type A method. However, the difference between this method and method A is that the flip does not happen in the end patch cords, but in the array cable itself. In this case, the fiber at position 1 on one end of the cable is shifted to position 2 at the other end of the cable. The fiber at position 2 at one end if shifted to position 1 at the opposite end, etc.

Pros: This method requires one cassette type, easy to produce and purchase, and it can support both single-mode and multimode fiber.

Cons: An additional drawback to this method is that it does not support parallel optics and is less reliable than method A.

Conclusion

We have discussed three polarity methods for MTP system, and indicate the pros and cons of each one. For choosing the proper method for MTP system, you should weight both advantages and disadvantages.