Understanding MTP/MPO Connectivity in High Density Data Centers

With the prevalence of cloud computing and big data, there comes a more demanding request for high-speed transmission and data capacity than ever since. In this case, 40/100G networks are more commonplace and now become a trend and hotspot for data-center cabling system. Meanwhile, most IT companies have realized that MTP/MPO cassettes, patch cords, connectors and adapters are essential backbone to their infrastructure. So, we will explain some basic factors in MTP/MPO connectivity in this article, with the purpose of better understanding this connectivity method.

MTP/MPO Connector Explanation

The need for transmission speed and data volume over short distances must be satisfied by choosing the right type of connectivity. So let’s start from the most basic yet critical part of MTP/MPO connectivity—MTP/MPO connector. It is known that 40/100G transmission utilizes parallel transmission, in which the data is simultaneously transmitted and received over multiple optical fibers (click here to know more about serial transmission and parallel transmission), thus a multi-fiber connector is required. MTP/MPO connectors which have either 12 fiber or 24 fiber array, will better support this solution.

MTP/MPO connector is the up-and-coming standard optical interface for 40G and 100G Ethernet network. The terms “MPO” and “MTP” are used interchangeably for this style of connector. MPO is the generic name for this Multi-Fiber Push On connector style. While MTP is a registered trademark and identifies a specific brand of the MPO-style connector.

MTP/MPO connectors are pin and socket connectors-requiring a male side and a female side. Cassettes and hydra cable assemblies are typically manufactured with a male (pinned) connector. Trunk cable assemblies typically support a female (unpinned) connector. The connectors are also keyed to ensure that proper end face orientation occurs during the mating process.

Functions of MTP/MPO Connectivity in 40/100G Network

The widely used 10G system generally would utilize a single MTP/MPO (12 Fiber) connector between the 2 switches. Modules are placed on the end of the MPO connector to transition from a MPO connector to a 12 Fiber breakout LC duplex or SC duplex cable assembly. This enables connectivity to the switch. 40G and 100G systems require a slightly different configuration.

In 40G MPO connectivity system, an MPO connector (12 Fiber) is used. 10G is sent along each channel/fiber strand in a send and receive direction. This “lights up” 8 of the 12 fibers providing 40G parallel transmission.

For optical 100G MPO connectivity system, an MPO connector (24 Fiber) is used (or alternatively 2 x 12F MPO Connector). 10G is sent along each channel/fiber strand in a send and receive direction. This “lights up” 20 of the 24 fibers providing 100G parallel transmission.

MTP/MPO Connectivity Components

Along with MTP/MPO connector, there are some other MPO components that used in high-density network interconnection. In essence, part of the MTP/MPO connectivity solution is a variety of fiber optic cabling components. Generally, there are two types of cables used in this solution:

One is a standard MTP trunk which has an MTP/MPO connector on either end of a 12 or 24 fiber ribbon cable. The connector construction can vary to the point where the 24 fibers are terminated into a single MTP/MPO connector, or they can be terminated into 2 separate 12 fiber MTP/MPO connectors.

Another option used in this cabling configuration is a MTP/MPO breakout cable. This cable has an MTP/MPO connector on one end while the other end of the cable can have a variety of standard optical interfaces such as LC or SC connectors.

Moreover, these can connect directly into patch panels, MTP cassettes and active equipment. The MTP/MPO cassettes provide a central patching and fiber optic breakout point where the MTP interface can be changed to SC or LC type interface. MTP/MPO cassettes are typically housed in patch panel or fiber storage tray.

Conclusion

In summary, MTP/MPO connectivity solution has proven to be an effective, feasible and flexible option to achieve 40/100G transmission, especially with the case of large- capacity and high-density data center environment. Not to mention that it also provides a reliable alternative for quickly connecting and rapid deployment. Hope the information offered in this article could at least help you understand this connectivity method. And for more information about MTP/MPO connectivity tutorial and products, please visit www.fs.com.

Source: http://www.fiber-optic-solutions.com/mtp-mpo-connectivity-data-centers.html

Considerations for Smooth 40/100G Migration with Fibers

We are now basking in a great boom in data transmission and information exchange, which results in an ever growing demand for higher speed and more reliable network. Currently, to migrate from legacy 10G to 40/100G network has become a hot topic yet irreversible trend. Part of this evolution, of course, was installing fiber optics in more network interconnection scenarios instead of copper cable. Among various connectivity methods, fiber optic cables have become the ubiquitous transport medium in the data center network. So, when employing fiber optic cable for 40/100G migration, some key considerations should be taken into account. That’s what we are about to explain in the following parts.

Selecting the Right Type of Fiber (Common Approaches Overview)

For data centers, the most cost effective fiber solution is a multimode fiber system. Surveys have shown that more than 80% of data centers are equal to or less than 100 meters. Moreover, multimode fiber transceivers are much less expensive than single-mode transceivers because they use a vertical cavity surface emitting laser (VCSEL) light source, which is easy to manufacture and package.

Although single-mode cable is less expensive, while concerning the total system cost of multimode versus single-mode, multimode becomes significantly less expensive. Thus selecting the right type of fiber will do you a good return in the long run. The following diagram presents some common approaches used in data centers. Each approach uses short-wavelength (850 nanometer) transmission over multimode fiber.

According to the diagram, it is clear that the fiber system should be designed with OM3 or OM4 MMF to support 10G and beyond applications. OM3 supports 10G up to 300 meters, but only supports 40/100G up to 100m. OM4 supports 10G up to 550 meters, but only supports 40/100G up to 150 meters. If planning to support 40/100G in the future, the channel cannot be designed for the maximum distances that 10G can support. You should better design for the application that has the most stringent requirements (usually the fastest data rates) even if the application is a future installation.

Several Other Important Factors

Besides selecting the type of fiber, there are several other essential considerations to enable successful 40/100G migration. Which include channel insertion loss, polarity and alignment pins.

Channel Insertion Loss (Loss Budget)

The channel insertion loss is made up of the insertion loss (IL) of the cable, the insertion loss of all mated connector pairs and the insertion loss of splices in that channel. And as the data rate increases from 10 Gbps to 40/100 Gbps, the total channel insertion loss decreases noticeably. The following picture shows total loss budgets for a 100-meter channel at different data rates common to current Ethernet applications. As data rates progress from 100 Mbps Ethernet-based systems to 10 Gbps Ethernet-based systems, the optical loss budgets have shrunk considerably from 11 dB to 2.6dB. 40/100 Gbps Ethernet systems have an even smaller budget of 1.9 dB when using OM3 or 1.5dB when using OM4.

Polarity

Proper polarity ensures an optical path from the transmit port of one device to the receive port of another device. There are several different methods to maintain polarity, but do remember that the different methods may not be interoperable.

Generally, there are three methods depicted in the TIA standards: Methods A, B and C (for more details click here). And each method requires a specific combination of components to maintain polarity. Here we take duplex signaling which uses an MPO backbone cable, cassettes and patch cords for example. The following shows the component options that are used in specific combinations for each of the polarity methods:

• MPO-to-MPO backbone cables: Type A, B or C
• MPO-to-LC cassettes: Method A or Method B
• Patch cords: Type A-to-A or Type A-to-B

Polarity becomes more complicated when migrating to 40/100G because parallel transmission replaces duplex transmission. Parallel optical fiber links integrate multiple transmitters in one transmitter module, multiple fibers in fiber array connectors and multiple receivers in one receiver module. Multiple transmitters and receivers may also be integrated together in a transceiver module.

Alignment Pins

When mating connector plugs that use alignment pins, like the MPO connector, it is critical to ensure that one plug is pinned and the other plug is unpinned. Since general transceivers that accept MPO plugs are pinned, they accept only unpinned plugs. The picture below shows an MPO connector with pins installed.

The pinned connector is typically located inside the panel to help protect the pins from being damaged (i.e. the fixed connector is pinned and the connector that is frequently removed and handled is unpinned). For example, cassettes are typically pinned and trunk cables are typically unpinned. Do make sure the alignment pins are properly cleaned, or it could collect debris around the pins, which results in the two components not mating correctly.

Conclusion

To sum it up, for fiber installation in 40/100G migration, multimode fibers systems are more common and cost effective than single-mode systems for short distances. Select at least OM3, while OM4 will provide longer distance support or more connections over shorter distances. Channel insertion loss is the foundation, so consider high-performance, low loss components. Moreover, consider the polarity method to be used and for parallel transmission uses array connectors, decide which components require pins and which do not.

Source: http://www.china-cable-suppliers.com/tips-40100g-migration-fibers.html

Serial Transmission vs. Parallel Transmission

We know that in data centers and server farms, when peripherals are attached to a computer, a physical cord is required to send signals back and forth. In this case, the processor can communicate with these devices and send data to them. Communication occurs when the computer sends electronic pulses to the peripheral or vice-versa. Basically, there exist two primary types of digital data transmission—serial transmission and parallel transmission. Then, is there any difference between these two methods of data transmission? How to apply them in data center connectivity? This is what exactly we are going to discuss.

Serial Transmission and Parallel Transmission Overview

For each and every data transfer, the same protocol should be applied to the emitter and the receiver. It enables them to have the same level of information and to know the transfer speed of the data. There are numerous protocols though, and all protocols rely on these two transmission methods: serial transmission and parallel transmission.

Serial Transmission

In serial transmission, bits are sent sequentially on the same channel (wire), one bit at a time. In this way, it reduces costs for wire but also slows the speed of transmission. Also, for serial transmission, some overhead time is needed since bits must be assembled and sent as a unit and then disassembled at the receiver. Serial transmission can be either synchronous or asynchronous.

Parallel Transmission

In parallel transmission, multiple bits (usually 8 bits or a byte/character) are sent on different channels (wires, channels) simultaneously within the same cable, or radio path, and synchronized to a clock. Parallel devices can transfer data in words of one or more bytes at a time. Consequently, there is a speedup in parallel transmission bit rate over serial transmission bit rate, and the cost increasing parallelly since multiple wires cost more than a single wire. As the cable gets longer, the synchronization timing between multiple channels becomes more sensitive to distance. Unlike serial transmission, parallel transmission is considered synchronous.

Transmission Methods Applied in Data Centers

We know that both serial transmission and parallel transmission take a seat in data center connectivity, but in different situations and applications. In the following parts, we will illustrate it in details.

Serial Transmission for 10G Network

Serial transmission approach is usually employed in 10G fiber connectivity where the data are sent sequentially. A duplex fiber pair that consists of one dedicated transmission fiber and one dedicated reception fiber creates the 10G channel to complete the data circuit. Typically, serial connectivity is achieved by using a duplex LC connector. The LC connector is the most commonly deployed interconnect in data centers, especially for high-density network applications.

Parallel Transmission for 40G Network and Above

Currently, it’s still not feasible yet possible to adopt a single duplex fiber for beyond 10G network. Although, the technical advancements in serial transmission have raised the limit to 25G, 40G network and above demands for parallel transmission since it can transport more data and achieve higher speeds. For example, parallel transmission achieves the 40G speed by combining four 10G duplex fiber pairs to create a 40G channel. A 100G channel would include ten 10G duplex fiber pairs, and so on. The same principle applies for 120G network and higher.

However, parallel transmission principles can also be applied to 25G duplex fiber pairs to reach even higher speeds or reduce the number of fibers required at a given speed. For instance, a 100G channel would require four 25G duplex fiber pairs instead of ten 10G duplex fiber pairs.

In parallel transmission, MPO/MTP connectors are used to achieve connectivity. They either house 12 or 24 fibers (6 or 12 duplex fiber pairs). This connectivity option finds itself a better place in data centers because it can take advantage of low-cost lasers and multi-mode cables. Equipment designed for speeds of 10G or less has two-strand, duplex fiber ports for serial transmission, while 40G and 100/120G equipment has 12- and 24-strand MPO/MTP fiber ports for parallel optics transmission.

Conclusion

As the basic digital data transmission approaches, serial transmission is often used in 10G connectivity or data transfer with great distances. While for 40G and beyond or short distance transmission, parallel transmission is preferred. Hope you could acquire some useful information from the article, and have a better understanding of these two data transmission methods.

First published: http://www.china-cable-suppliers.com/serial-transmission-vs-parallel-transmission.html

Do You Know Enough About Fiber Connectors?

As there exists a wide range of splice options for fiber network available on the market, selecting the right connector for your application can sometimes be tough and confusing. While choosing the fiber connector, various factors like cost and availability should be considered, which naturally lead to even less thought goes to connector itself. Since each connector has its own unique design as well as merits and demerits, it can pose a significant influence on deployment speeds and costs in the long run. So before making your decision, you’d better have an overall understanding of fiber connectors, and this is what we will talk about.

Fiber Connectors Overview

In this part, we will introduce some fiber connectors that are commonly used in the network applications. The following diagram directly explains the differences among them in performance.

Name	Mating Cycles	Ferrule Size	Typical Insertion Loss (db)	Application Features
SC	1000	2.5 mm Ceramic	0.25-0.5	Mainstream, Reliable, Fast deployment, Field fit
LC	500	1.25 mm Ceramic	0.25-0.5	High density, Cost effective, Field fit
FC	500	2.5 mm Ceramic	0.25-0.5	High precision, Vibration environments, Field fit
ST	500	2.5 mm Ceramic	0.25-0.5	Military (legacy), Field fit
MTP/MPO	1000	6.4*2.5 mm molded	0.25-0.75	High density, Aggregate networking, Fast deployment

SC Connector

SC connector was one of the first connectors presented on the market following the advent of ceramic ferrules. It has a push-pull coupling end face with a spring loaded ceramic ferrule. Initially intended for Gigabit Ethernet networking, it became increasingly popular as manufacturing costs came down. The SC connector has held a dominated position in fiber optics for over a decade with only the ST rivaling it. And it still remains the second most common connector for polarization maintaining applications. The SC is ideally suited for datacoms and telecoms applications including point to point and passive optical networking.

LC Connector

Considered to be the modern replacement of the SC connector, LC connector is also a push-pull connector, but it utilizes a latch as opposed to the SC locking tab and with a smaller ferrule it is known as a small form factor connector. LC connector shares huge popularity in datacoms and other high-density patch applications. And its small size and latch feature make it an ideal alternative for densely populated racks and panels. Since LC compatible transceivers and active networking components have been introduced, LC connector is likely to continue to grow steadily.

FC Connector

FC connector leads the trend to use a ceramic ferrule, but unlike the plastic bodied SC and LC, it utilizes a round screw-type fitment made from nickel-plated or stainless steel. In spite that the manufacturing and installation of FC connector are much more complex, it’s still an optimum option for precise measuring equipment such as OTDRs. Moreover, FC connector is particularly effective in high vibration environments, ensuring that the spring-loaded ferrule is firmly mated.

ST Connector

ST connector looks much like FC connector, but it uses a bayonet fitment rather than a screw thread. Deployed predominately in multi-mode datacoms, it is most common in network environments such as campuses, corporate networks and in military applications where the quick connecting bayonet had its advantages at the time. However, it cannot be terminated with an angled polish, which limits use in single mode fiber and FTTH applications.

MTP/MPO connector

MTP and MPO connector falls into the category of multiple fiber push-on/pull-off connector. It is larger than other connectors since it can support up to 24 fibers in a single ferrule. It is currently extensively used in high density patch environments such as data centers, both at single mode and multi-mode wavelengths. MTP/MPO connector is often supplied with a fan-out assembly at the opposing end (such as LC, SC FC etc.). This allows the operator to change channels simply by re-patching the fanned-out side of the cable.

Conclusion

Getting to know the differences between various types of fiber connectors simply contribute to the primary stage of selecting the right one. And when it comes to the planning process of fiber deployments, the differences can be much more clearly. So, make sure to invest enough time to select the right fiber connector, which will do you a good return in the long run.

First published: http://www.china-cable-suppliers.com/know-enough-fiber-connectors.html