Things to Know About 40G QSFP+ AOC

As the demand for reliable, efficient and fast data transfer continues to heat up, the need for a more capable alternative to traditional copper cables also grows parallel with it. Achievements in network technologies have ushered in a new era with higher speed connectivity, thus migration from 10G to 40G nowadays is no longer a fresh topic but an irresistible trend. The active optical cable (AOC), since it was introduced in 2007, has been considered to be an optimum option for 40G support connectivity. This article will explain some vital elements in related to 40G QSFP+ AOC in detail.

40G QSFP+ AOC Description

40G QSFP+ AOC, as the name indicates, is a type of active optical cable used for 40G networks and applications. It is terminated with 40G QSFP+ connector on one end, and on the other end, it can be terminated with QSFP+ connector, SFP+ connector or LC connector etc. The QSFP+ optical modules provide four parallel full-duplex transmit and receive channels, each capable of 10Gbps operation and in total 40Gbps aggregate bandwidth of at least 100 m over multimode fiber.

With a bit error rate (BER) exponentially better than that of copper cables, along with being lighter and with a tighter bend angle, AOCs have since become mass-produced for data centers and server rooms all over the world.

40G QSFP+ AOC

How Does AOC Work?

The feature that distinguishes AOCs from traditional types of connectors is the fact that data passes through optical fiber lanes as opposed to copper, while maintaining a traditional electrical connectivity interface. Besides, optical cable possess a greater capability to carry a high-speed signal over longer distances than any other types of cable, without compromising signal integrity. Not to mention that it ensures data security and non-conductivity.

All active optical cables are comprised of four main functional parts:

1. High-density connector: The form factor of the connector equipped to either side of the optical fiber cable can come in many variants to fulfill a variety of functions, whether in QSFP+ format for data centers and server rooms or HDMI format for consumer entertainment.

2. Ribbon optical fiber cable: A multi-channeled optical fiber cable (that could come in multi or single-mode) ranging from 1 to 100 meters in length.

3. Full-duplex AOC transceiver: An optical transceiver is embedded into either side of the optical cable, two optical-electrical and electrical-optical converters on either side of the cable.

4. MPO optical connector: A connector that is permanently fixed to the form factor shell and fiber, designed to shield the optical interface from external interference.

Diagram of AOC

Comparison Between 40G QSFP+ AOC and QSFP+ Optics

Currently, 40G QSFP+ AOC is becoming increasingly popular in data centers, especially those are supposed to accommodate massive and high density bandwidth. Then, how dose 40G QSFP+ AOC differ from standard QSFP+ optics? And what we can benefit from employing 40G QSFP+ AOC? Here, we simply make a comparison between them from the perspective of total cost, insertion loss and return loss.

Cost—by adopting 40G QSFP+ AOC to your existing infrastructure, there is no need to use extra fiber patch cables. So, it generally costs less when compared with QSFP+ optic modules. Let’s just take QSFP+ to QSFP+ AOCs for example, it is usually employed to very short distance data transmission while offers a rather cost-effective way to establish 40G links between QSFP ports of switches within racks and across adjacent racks. Moreover, with 40G QSFP+ AOC, you will be free from cleaning the optical connectors as well as from termination plug and test when troubleshooting, which is time-saving and cost-efficient.

Insertion loss and return loss—when considering the repeatability and interchangeability performances within the same transmission distance, 40G QSFP+ AOC is superior to that of QSFP+ optics. Because when different fiber optic patch cables plug into the module, it will have the different insertion loss and return loss, which is the same even for the same module. However, an AOC is more stable and has better swing performance than other QSFP+ optics in this situation.

Conclusion

The 40G QSFP+ AOC is a high performance, low power consumption integrated cable for short-range multi-lane data transmission and interconnect applications. It has been widely used in high-density connectivity data centers to upgrade the current network equipment. 40G QSFP+ AOC also offers an optimum solution for high-performance computing and storage applications. So one can rely on 40G QSFP+ AOCs when designing for higher speed and more reliable network connectivity. For more detailed products information and interconnect solutions, please visit www.fs.com.

LC Uniboot Fiber Patch Cable – An Optimum Cable Management Option

With the ever lasting advancement of networking technology, there comes an increasing demand for data centers to accommodate higher density cables and more bandwidth. However, it is generally acknowledged that data centers are often with limited space. Then how to handle those massive cables in such circumstances becomes a vital issue. This article will introduce the LC uniboot fiber patch cable, an optimum alternative for cable management that is designed to deliver maximum connectivity performance.

LC Uniboot Fiber Patch Cables Description

LC uniboot fiber patch cable consists of two LC connectors that wrapped by a common housing with one boot. It is terminated on a single, round, two-fiber cable to achieve duplex data transmission. LC uniboot patch cable allows for up to 68% savings in cabling volume due to a compact design, and it can ensure easier maintenance and operability with tool-less field reversible polarity and color identification. All the features presented by LC uniboot fiber patch cable make it an ideal option for high density network environment.

LC uniboot fiber patch cable

Comparison Between LC Uniboot Fiber Patch Cables and Standard Ones

LC fiber optic connectors offer higher density and better performance in most environments when compared with other fiber optic connectors, making it a reliable and popular choice for many applications and equipment. This can explain why uniboot fiber patch cables are terminated with specially designed LC connectors. The innovative LC uniboot fiber patch cable, with its unique structure and compact design, performs even better than standard LC fiber patch cables in high density cabling environment. Here, we present the obvious differences between the LC uniboot patch cable and the standard LC fiber patch cable in the following picture.

LC uniboot fiber patch cable vs.standard fiber patch cable

Features of LC Uniboot Fiber Patch Cables

Genarally, there are three primary features concerning the uniboot fiber patch cables:

Adjustable Pitch—the unique style of the clip allows the LC Connectors to easily adjust for the increasing demand of a 5.25 pitch, as well as the standard 6.25 pitch. Eliminating the requirement for hybrid patch cables.

Reverse Polarity—with a few simple steps, the connectors polarity of the LC uniboot fiber patch cables can be reversed at will without connector re-termination.

Quick Release Latch—the latch of LC uniboot fiber patch cable allows for the quick and easy release of this connector from the adapter panel, which makes great sense in the growing trend of high density applications.

What LC Uniboot Fiber Patch Cables Can Achieve?

As we have mentioned previously, LC uniboot fiber patch cables are especially vital to space sensitive data centers and high density cabling environments, so what exactly we can benefit from deploying LC uniboot fiber patch cables?

Cable Congestion Reduction

With two fibers for duplex transmission firmly enclosed in a single cable, LC uniboot fiber patch cable effectively cuts down the cable count up to 50% compared with the standard LC duplex patch cords. Thus the space requirement of cabling can be significantly reduced by it, naturally result in less chance of cable congestion in data centers.

Effective Polarity Reversal

Changing the polarity of a standard LC duplex fiber patch cable may be annoying to many data center operators, especially when there happens to be a high density cabling system. This is sort of a time and energy consuming task since some minor mistakes could lead to various troubles. However, with LC uniboot patch cable, the polarity replacement can be much easier even without any additional tools. In terms of different types of LC uniboot patch cables, the polarity reversal steps may vary. We just illustrate two most used ones as follows.

LC uniboot polarity reversal

Conclusion

To address the increasing demand for high density applications and smaller fiber cable, the LC uniboot fiber patch cable is designed to help cut down cabling space and provide more effective polarity reversal solution, and to streamline cable management and logistics. Without doubt, LC uniboot fiber patch cable is the savior of popularized high-density cabling system. Hope this article could help you to choose the right LC uniboot patch cable for your applications, and for more products information and solutions, please visit www.fs.com.

Pre-Terminated Cabling System—An Ideal Solution for Data Centers

When designing and implementing their high-density networks, most data center managers and operators are inclined to options which are more sustainable and environmentally sound. They always expect systems to provide high performance and reliability for maximum network uptime over the long term. Since the demand for higher bandwidth and flexibility for future growth never ending, network administrators now are seeking to the network’s physical media infrastructure to achieve these goals. And the growing adoption of pre-terminated cabling system serves as one of the trend, that is what we will explain in this article.

What Is Pre-Terminated Cabling?

Then what the pre-terminated cabling system refers to and how it differs from field terminated one? In fact, pre-terminated cables go through the same procedures as field terminated cables, but these steps are taken at the manufacturer’s facility or cable assembly house and delivered to the job site with the connectors already terminated, properly polished, and the entire cable assembly tested on either both or one end. Which helps to eliminate the necessity for on-site field termination. Compared with field terminated cabling products, pre-terminated fiber cable assemblies are more convenient and flexible. They are most suited for network installations that are planned well in advance, taking into account both current and future requirements.

What Pre-Terminated Cabling System Can Achieve?

Installing and connecting your cable infrastructure in the data center consists of various labor intensive tasks. And manual field terminations, troubleshooting, and error corrections also extended deployment times, higher installation costs and increased downtime. However, with the deployment of pre-terminated cabling system, you are supposed to benefit from it with the following aspects:

  • Installation time and costs are substantially reduced.
  • Material reductions of 50 percent or more are typical when using pre-terminated systems rather than traditional systems.
  • Network performance and reliability are assured due to in-factory testing and validation of components.
  • Modular components at the physical layer are reusable. They can be disassembled and repurposed to accommodate moves, adds and changes, which provides greater flexibility and portability, as well as a clear migration path to support new technologies and applications as an organization grows and requirements change and evolve.
  • Pre-terminated installations are more precisely planned, which results in a neater, cleaner appearance, as well as faster and easier cable management, maintenance and troubleshooting.
Common Pre-Terminated Fiber Cables

It is undeniable that pre-terminated fiber cabling system indeed offers a constructive and ideal solution to data center management and maintenance. Here in this part, we will further introduce some most commonly employed pre-terminated fiber cables, including fiber patch cables, fiber optic pigtails and MTP/MPO pre-terminated cables.

Fiber Patch Cables

As one of the most used components in fiber optic networks, fiber patch cables help to ensure a reliable temporary fiber optic interconnection. There exists a wide range of fiber patch cables on the market, available in single-mode and multimode versions with PVC, LSZH, OFNP or armored jacket. And connection type options involve LC, FC, SC, ST, MU, MTRJ and E2000 pre-terminated in duplex or simplex fiber. Fiber patch cables are suitable for all kinds of fiber optic connectivity applications.

fiber patch cable

Fiber Optic Pigtails

Fiber optic pigtail, which is a fiber optic cable of a specified length, has only one end terminated with the appropriate connector style and an open unterminated end. A pigtail can be fusion spliced onto a pre-terminated fiber optic cable assembly to extend the cable distance or onto field-terminated cables to provide the connectorized end. Pigtails do not need the same configuration or connector style as the opposite end. Keep in mind that when installing pigtails, you must be trained and will need additional equipment, such as a fusion splicer and fusion splice trays.

fiber optic pigtail

MTP/MPO Pre-Terminated Cables

Pre-terminated with high-quality and low loss MTP/MPO connectors, this kind of cable can meet the high-speed, high-density, and wide bandwidth demands of the current and future network. Basically, both MTP/MPO trunk cables and MTP/MPO harness cables are classified into this category. They are available in any fiber mode (single-mode, multimode and 10G multimode) and a full range of length options.

MTP/MPO trunk cable

Conclusion

Pre-termination cabling is not just a popular trend, it is an increasingly popular way of delivering a project in a more timely and cost effective manner. Which on the whole can provide benefits for all sizes of project.

How to Choose a Rack Cabinet

It is a commonplace nowadays to employ rack cabinets in data centers and other modern IT installations alike. Humble as the appearance is, rack cabinet actually plays a significant role in security and regulatory compliance, configurability, cooling and efficiency, as well as system availability. Moreover, it also helps to save much more space which is considered to be vital and precious for data centers. In this article, we will discuss how to choose a right rack cabinet that better fit your expectation.

What Is Rack Cabinet?

A rack cabinet is a closed frame, specifically designed for holding monitors, servers, various networking equipment, electronic components, measuring instruments and other similar devices. Most commonly, the rack cabinets are installed for storing network equipment and servers. The rack cabinets provide an easy access to the networking equipment while enabling airflow, and they keep the working space well-organized.

rack cabinet

Rack cabinets are widely and intensively adopted to server rooms and data centers, audio/video installations, closets housing telecommunications equipment, and industrial environments such as a factory floor.

Common Types and Sizes of Rack Cabinet

Basically, there exist two types of rack cabinets in terms of different working conditions and requirements: floor standing rack cabinet and wall mount rack cabinet. If access control and equipment protection are important to you, floor standing rack cabinet is proved to be a desirable choice. While wall mount rack cabinet are ideal for securely housing IT equipment in classrooms or sites with limited floor space.

“Rack unit” is used to describe the height of a rack and the height of equipment in it. (a rack unit is 1.75 inches, or 44.45 mm). The actual height of a 42U rack is therefore 42 x 1.75 = 73.5 inches. A 2U server would occupy two of the available 42 rack units.

1 rack unit

Since the rack cabinet come in different sizes, when choosing a specified rack for your infrastructure you should at least take two factors into consideration: type of equipment to be stored inside and amount of space that is required. Be sure to make an accurate assessment of the amount of rack space you currently need, and allow for future growth.

In addition, before installing the rack cabinet, you need to make sure that the equipment to be placed in will match the rack cabinet. So the maximum rack depth required to mount your equipment should be taken into account. The rack depth of floor standing and wall mount rack cabinet is different, which will be explained in the following diagram.

Floor standing rack depth designation
Rack Depth (in.) Ideal for…
Shallow 27 A/V equipment, limited space
Mid-depth 31 Limited space
Standard 37 Servers
Deep 42 Extra cables, improved airflow
Wall mount rack depth designation
Rack Depth (in.) Ideal for…
Patch-depth < 16 Patch panels
Switch-depth 16-23.99 Switches
UPS-depth 24-31.99 UPS systems
Server-depth > 32 Servers
Benefits of Good Rack Cabinets

In terms of the benefits that every rack cabinet should provide, basically there are three main advantages:

Security—because the front and rear doors and side panels on most rack cabinets can be locked, access to equipment and sensitive data can be managed and controlled.

Great cooling flexibility—heat-sensitive equipment such as servers is isolated inside rack cabinets, allowing for more control over both active and passive airflow/cooling management.

Equipment protection from harsh environments—if your rack and equipment is going to be in harsh environments where dust, water and other debris could damage your equipment, a rack cabinet that protects equipment from the elements is for you.

Conclusion

IT infrastructure continues to expand and the need to organize, secure and cool servers, routers, hubs and PDUs is continuously increasing. Meanwhile, conserving space for future growth becomes more critical. All of these make rack cabinets an essential application in cutting-edge data center worldwide. I hope what we discussed above would assist you when you’re looking to purchase a rack to mount your servers and other network equipment.

Fiber Termination Box Overview

Fiber termination box (FTB), known as optical termination box (OTB) as well, is a compact fiber management product of small size. It is widely adopted in FTTx cabling for both fiber cabling and cable management. In some circumstances, fiber termination box can be regarded as the mini size of fiber optic patch panel and optical distribution frame (ODF).

Fiber Termination Box Classification

Currently, the market embraces a great amount of fiber optic termination boxes and other devices for cable management. And the names and model numbers of these fiber termination boxes vary from the design and idea of different manufacturers. Hence to identify the detailed classification of fiber termination box could be a hard task.

Roughly, fiber termination box can be categorized as fiber optic patch panel and fiber terminal box according to the size and applications. Judging by the appearance, fiber patch panel is of gibber size whereas fiber terminal box is smaller.

Fiber Patch Panels

Fiber patch panels are of wall mounted type or mounted type usually with 19 inch size. Generally, there is a tray inside the fiber box that helps to hold and protect the fiber links. Various different kinds of fiber optic adapters can be pre-installed in fiber patch panels as the interface, via which the fiber box could connect with the external devices.

Fiber Terminal Boxes

Besides fiber patch panels, one can also count on fiber terminal boxes for fiber distribution and organization. While typical fiber terminal boxes are with 12 ports or 24 ports, 8 ports, 36 ports, 48 ports and 96 ports fiber are available in the markets now. They are often installed with FC or ST adapters on the panel, either on the wall or put in horizontal line.

According to the design, FTB can be further divided into wall mount type and rack mount type.

The wall mount fiber termination boxes are designed for either pre-connectorized cables, field installation of connectors, or field splicing of pigtails. They offer an ideal solution for building entrance terminals, telecommunication closets, main cross-connects, computer rooms and other controlled environments.

wall mount FTB

The rack mount slide-out type fiber termination box usually for fiber splicing, distribution, termination, patching, storage and management in one unit. They support both cross-connect and interconnect architecture, and provide interfaces between outside plant cables and transmission equipment.

rack mount FTB

Moreover, in terms of installation environment, there are indoor FTB and outdoor FTB.

Indoor fiber termination box acts as the transition point between the risen cable and the horizontal cable, in this way, it provides operators much more flexibility when managing cables. Besides, indoor FTB makes it possible to leave space for overlength and terminated fibers, as well as for fiber splicing.

The outdoor fiber terminal boxes are environmentally sealed enclosures to distribute fibers for FTTX networks. They are also designed for fiber splicing, termination, and cable management.

Features of Fiber Termination Box

Fiber termination box contains the shell, the internals (supporting frame, set fiber disc, fixing device) and optical fiber joint protective element. Prominent advantages of fiber termination box lie in efficient cable-fixing, welding and its protective role in machinery of the optical fiber.

A insulation is always demanded between cable metal components and cable terminal box shell in a fiber termination box, which provides space for cable terminal and remained fiber storage. In addition, fiber termination box also facilitate the installation of different occasions since it is easy to access, which turns out to be time and cost saving.

Fiber Termination Box Application

Fiber termination box is universally used in telephone, agricultural telephone network system, data and image transmission system, CATV cable television series, indoor cable through force access and branch connection. Fiber termination box is available for the distribution and termination connection for various kinds of fiber optic systems, especially suitable for mini-network terminal distribution, in which the optical cables, patch cores or pigtails are connected. In addition to that, fiber termination box can be applied to joint fiber pigtail, protect fiber optic splices and share out the connectivity to individual customers.

Conclusion

Fiber termination box nowadays plays an indispensable role in the field of communication network with greater reliability and flexibility. This article may simply provide you a guideline when choosing fiber termination box for your infrastructure, for more detailed information and tutorial, please visit www.fs.com.

Related Article:1000BASE-X SFP Modules Overview

Things to Know About Bend Insensitive Multimode Fiber

Bend insensitive multimode fiber (BIMMF) has become a very active area within the telecommunication industry once it was introduced and popularized. It typically signifies technical advancements in the production of multimode optical fiber for easier installation, and cable management for multimode fiber cables through improvements in bend insensitivity. This article will focus on some useful information about BIMMF from the perspective of its working principle, performance in networking and unique advantages as well.

What Is Bend Insensitivity?

An optical fiber consists of a core and a cladding. Although both of these regions are made from glass in telecommunications grade fibers, they are significantly different from each other. Each region is designed to capture light within the core and transmit it to the opposite end of the fiber. During this process, the light may follow many paths, depending on the angle at which the light hits the boundary, it is either reflected back into the core, or it gets lost into the cladding. Therefore, the light losses during transmission cause a weaker optical signal at the other end.

light traveling in fiber

Optical fiber is sensitive to stress, particularly bending. When conventional fibers are bent tightly, some of the signal will leak out of the fiber at the site of the bend due to macrobend loss, which will results in system failure and unplanned downtime. Various attributes in the fiber determine when this occurs. The relative ease with which this happens is known as bend sensitivity. On the contrary, bend insensitivity is a positive feature that can provide for additional robustness and simplify installation of multimode fiber.

Introduction to Bend Insensitive Multimode Fiber (BIMMF)

Bend-insensitive multimode fiber (BIMMF) has an innovative core design that enables it to significantly reduce macrobend loss even in the most challenging bend scenarios. It is hence natural that bend insensitive multimode fiber can withstand tough treatment. The difference between traditional multimode fiber and BIMMF mainly lies in the fact that the BIMMF design can include an optical trench. This trench effectively improves the fiber’s macrobend performance by retaining more of the light that would have escaped the core of a traditional multimode fiber. So when compared with standard multimode fibers, BIMMF is proved to be a good candidate for loss and bend critical applications because of their higher immunity to bending losses, without loosing performances or compatibility to other standard high bandwidth multimode fibers.

Compatibility With Conventional Fibers

There is a lot of buzz around the issue of bend insensitive fiber— is it compatible with regular fibers? Can they be spliced or connected to other conventional fibers without problems? Modeling and testing on BIMMF has shown that an optimized BIMMF is backward compatible and can be mixed with non-BIMMF without inducing excess loss. Hence, BIMMF and MMF could easily be mixed in an optical channel without complicating the estimation of losses. Moreover, BIMMF may lead to higher tolerance to possible misalignments when two connectors are mated. This is an additional positive feature for 40 and 100 Gigabit applications.

In summary, a well-designed BIMMF complies with all relevant industry standards and adheres to the following:

  • BIMMF OM2, OM3 and OM4 multimode fibers are fully compliant and fully backward-compatible with all relevant industry standards.
  • BIMMF is fully backward-compatible and may be used with the existing installed base of 50/125um multimode grades including OM2, OM3 and OM4.
  • BIMMF may be spliced or connectorized to conventional 50/125um fiber types with commercially available equipment and established practices and methods, no special tools or procedures are required.
  • BIMMF not only meets all relevant macrobend standards, but sets a new level of bend performance.
Advantages of BIMMF

Bend insensitive multimode fiber is available in all laser optimized grades, OM2, OM3 and OM4, and exhibits 10 times less signal loss in tight bend scenarios and therefore protects enterprise and data center systems from unplanned downtime due to signal loss and associated significant revenue loss.

This fiber type offers extremely low bending loss at both the 850 and 1300 nm operating windows, while maintaining excellent long term fiber strength and reliability. The fiber can be installed in loops as small as 7.5 mm radius with less than 0.2 dB bending loss at 850 nm and 0.5 dB at 1300 nm.

Maximum induced bend loss performance at 850 nm Standard for multimode fibers IEC 60793-2-10 Bend Insensitive MMF (no standard currently)
Bend radius 37.5 mm 7.5 mm
Number of turns 100 2
Conventional MMF 0.5 dB
Bend Insensitive MMF 0.05 dB 0.2 dB

In addition, bend insensitive multimode fibers enable new possibilities for cable and patch panel design to further improve the benefits of using fiber. Optical cable manufacturers can now design thinner, more flexible trunk cables, making for easier cable installation and further improving airflow in conduits, patch panels and racks. Due to the ability of the fib cable to be bent tightly with significantly less signal loss, connector modules can be made smaller which in turn leads to an increased density within racks and smaller racks.

Conclusion

Bend insensitive multimode fiber has been widely employed to enhance fiber management in data centers, high performance computing and enterprise LANs. Since it is a real advance to current standard multimode fibers, BIMMF is recommended for bend and loss critical applications. What should be noticed is that BIMMF also should be handled with appropriate care as all optical glass fibers.

Introduction to Automatically Switched Optical Network (ASON)

Optical backbone networks which based on SDH/SONET and WDM technologies are designed mainly for voice applications. However, it gradually fails to satisfy current needs triggered by rapid growth of data traffic. Thus, resources available to users often cannot be allocated properly because of the inherent inflexibility of manually provisioned large-scale optical networks. While with the advances in optical component technology, a significant amount of attentions are attached to the emerging technology of Automatically Switched Optical Networks (ASON), which enables more dynamic and diversified networking that may change the network characteristics dramatically.

Definition of ASON

As its name indicates, an Automatically Switched Optical Network (ASON) is an “intelligent” optical network that can automatically manage the signaling and routing through the network. However, in traditional network backbone, it was rather necessary to configure cross-connections in the network elements, an optical switch for example, to create a new traffic path for a customer. ASON is an optical transport network with dynamic connection capability, and this capability is achieved by using a control plane that performs the call and connection control functions. ASON aims to automate the resource and connection management within the network.

ASON uses the Generalized MPLS (GMPLS) signaling protocol to set up and monitor edge-to-edge transport connections. Switching technologies used in ASON range from single fiber switching to wavelength switching and to optical packet switching. And the components required for the switching are optical cross connects (OXCs), wavelength converters and optical add/drop multiplexers (OADMs).

Importance of ASON in Optical Network

In an optical network which is not based on ASON technology, when it comes to the need for more bandwidth, a new connection may be required. Thus the service provider must then manually plan and configure the route in the network, which is proved to be time-consuming. Moreover, it would waste a lot of bandwidth thus to cause inevitable problems to the whole network since bandwidth is increasingly becoming a precious resource. And the optical networks in the near future bear expectations to efficiently handle resources. ASON can fulfill some of these requirements for optical networks, which are listed below:

  • Fast and automatic end-to-end provisioning
  • Fast and efficient re-routing
  • Support of different clients, but optimized for IP
  • Dynamic set up of connections
  • Support of Optical Virtual Private Networks (OVPNs)
  • Support of different levels of quality of service

What should be noticed is that these requirements are not restricted to optical networks but can be applied to any transport network.

Architecture of an ASON

The layered transport plane, also referred to as data plane, represents the functional resources of the network which conveys user information between location. Transfer of information are either bi-directional or unidirectional. The transport plane can also provide transfer of some control and network management information.

Basically, the logical architecture of an ASON can be divided into 3 planes: transport plane, control plane and management plane.

The transport plane contains a number of switches, and these switches can either be optical switch or other types. Which are responsible for transporting user data via connections. These switches are connected to each other via physical interface (PI).

The control plane is responsible for the actual resource and connection management within an ASN network. It consists of a series of optical connection controllers (OCC), interconnected via network to network interface (NNIs). These OCCs have the following functions:

  • Network topology discovery (resource discovery)
  • Signaling, routing, address assignment
  • Connection set-up/tear-down
  • Connection protection/restoration
  • Traffic engineering
  • Wavelength assignment

The management plane, on the other hand, is responsible for managing the control plane. Its responsibilities include configuration management of the control plane resources, routing areas, transport resource in control plane and policy. It also provides fault management, performance management, accounting and security management functions. The management plane contains the network management entity which is connected to an OCC in control plane via the network management interface for ASON control plane (NMI-A) and to one of the switched via network management interface for the transport network (NMI-T).

ASON architecture

Conclusion

To sum it up, ASON can help to meet user requirements on a more realistic economical basis without resource consuming over-provisioning. Moreover, it also contributes to offering a good platform to realize a more cost-effective networking environment. I hope what presented above would help you to have a better understanding of ASON.

Related Article: A Comparison between Tee Coupler and Star Coupler

Fiber Optic Termination Overview

When installing a fiber optic network, appropriate fiber optic termination is considered to be an extremely important part since it can affect the performance and reliability of the whole network. It is hence natural that much attention should be necessarily attached to this area nowadays. Besides, an increasing number of products concerning fiber optic termination are appearing on the market to make the termination task easier and more accurate. The article will make an overview of fiber optic termination.

What Is Fiber Optic Termination

Generally speaking, fiber optic termination acts as the connection of fiber or wire to a device, the device can be something like a wall outlet or equipment that allows for connecting the cable to other cables or devices. Based on this, fiber optic termination enables fiber cross connection and light wave signal distribution. Proper fiber optic termination is able to meet the demand for protecting the fibers from dirt or damage while in use and preventing excessive loss of light as well, which also contribute to smooth and efficient performance of the network.

Preparing for Fiber Optic Termination

Before performing fiber optic termination, one should get well-prepared to ensure a smooth and successful process of termination. The preparation for fiber optic termination involves several steps: gathering the supplies you need, stripping the outer jacket, cutting the kevlar, and stripping the buffer or coating. For supplies, you’ll need safety glasses, a fiber disposal bin, connectors, fiber optic cable, epoxy and syringes (or anaerobic adhesive), and polishing film. Tools used in fiber optic termination usually include fiber stripper, scribe, aramid yarn scissors, adjustable cable jacket stripper, polishing puck, polishing glass plate, and a rubber pad to polish the PC connectors, especially for single mode termination. Besides, You’ll also need to test equipment such as a power meter, FO tracer, reference test cables, a LED light source and a microscope to view the connector.

Methods of Fiber Optic Termination

It is commonly believed that fiber optic termination is often time-consuming and highly specializes. However, due to the continuous advancement in termination technology, fiber termination systems currently demand less training and produce higher quality fiber connections in less time.

Basically, three widely adopted fiber termination methods are available to operators: pre-polished connectors, epoxy and polish fiber termination and pigtail connectors.

Pre-polished Connectors

Pre-polished connector has a short length of fiber already installed into the ferrule by the manufacturer of the connector. Moreover, the manufacturer also polished the ferrule end face thus there is no need to carry out this step on-site. The fiber to be terminated must be prepared using a specialist cleave tool and inserted into the rear of the connector where an index matching gel is often used to bridge the gap between the two fibers. The terminated fiber is held in place using some form of crimp or locking mechanism on the rear of the connector.

Epoxy and Polish Fiber Termination

This type of connector requires the application of some form of epoxy (glue) between the fiber and the connector ferrule that firmly bonds the two elements together once the epoxy has dried. There are a number of different types of epoxy available:

Heat Cured Epoxy — uses some form of “oven” to cure the epoxy, which can be selected for the optimum performance within pre-determined temperature ranges. The epoxy may either need to be injected in to the ferrule by the technician or the connectors may be supplied with the epoxy already injected by the connector manufacturer.

Ambient Temperature Epoxy— cures at room temperature without the need for any power, making it suitable for on-site terminations.

Fast Acting (Anaerobic) Adhesive — use an accelerant to speed the curing time. It can cause problems if the technician is unable to complete the insertion of the fiber into the ferrule before the epoxy cures.

Pigtail Connectors

Splice-on connectors are an alternative to either the pre-polished connector systems or the epoxy method of termination. A pigtail is a short length of 900 micron buffered fiber that has been factory terminated with a fiber optic connector. Thus it eliminates the need for any on-site termination or polishing of the connector. Splicing the end of the fiber of the pigtail to the end of the fiber of the cable, the pigtail is then attached to the cable. Fusion splicing is a preferred splicing method, where the two fibers are melted together using a high powered electric arc, forming one, single, continuous strand of glass.

Pigtail

Fusion splicing often requires the use of precision fiber cleaving tools and a fusion splicing machine. The fusion splice machine is used to align the two fiber end faces automatically and fuse the two together to create a very low loss joint.

Fusion splicer

Conclusion

Since fiber optic termination is an indispensable part of the optical network installation, we should always keep in mind the importance of it and get fully prepared before performing the task. Moreover, selecting a proper and efficient termination method could also help to ensure the excellent performance of the network.

Introduction to Fiber Optic Cleaving

Optical fiber has brought changes to the telecommunication industry throughout the world, therefore, it is essential for us to learn some skills necessary for working with optical fiber. It is known to all that when adopting or splicing a fiber, clean ends should be assured. And cleaving serves as one of the basic and important steps to ensure fiber ends clean and smooth, thus the significance of cleaving process cannot be underestimated. This article aims at providing some basic knowledge about cleaving and introducing common tools for cleaving.

Basics of Fiber Optic Cleaving

Fiber optic cleaving is one of the several processes in the preparation for a fiber splice operation. The purpose of cleaving is to prepare the end of the fiber so that it makes a very nearly perfect right angle with the body of the fiber and that this end face is nearly perfectly smooth. With a well-performed cleaving operation, a clean and flat endface was created perpendicular to the length of the fiber, with no protruding glass on either end. Besides it can also help to achieve a successful low loss splice of an optical fiber.

The technique of Fiber Optic Cleaving

A general strategy involved in the technique of fiber optic cleaving is known as the scribe-and-tension or scribe-and-break strategy. With the use of cutting tool made from materials such as diamond, sapphire or tungsten carbide, this process involves the introduction of a crack in the fiber, then followed by the application of tensile stress in the vicinity of the crack.

Cleaving technique

However, the specific implementations of the cleaving can be various thus lead to cleaves of different qualities. Some implementations may apply the tensile force uniformly across the cross section of the fiber while others might bend the fiber around a curved surface, causing excessive tensile stress on the outside of the bend. Besides, the crack in the fiber may also be generated in different ways: the crack may be introduced at a single point on the circumference or it may be generated all along the circumference of the fiber prior to the application of the tensile force. The circumferential introduction of the crack often allows fibers of considerably large diameters to be cleaved while maintaining high quality of the cleave.

Common Cleaving Tools

Basically, there are two kinds of cleaving tools which are commonly employed in fiber optic cleaving: pen-shaped scribe and mechanical cleaver.

Pen-shaped scribe looks like a ballpoint pen, but with a small wedge tip made of diamond or other hard material that is used to scratch the fiber manually. After scratching the fiber, the operator pulls the fiber to break it. In essence, both the scribing and breaking process are under manual control, making it more dependent on operator technique and less predictable as they require operators to exert force manually for breaking the fiber. So, an experienced operator is required to produce good cleaves.

Fiber optic scribe

And the other tool is mechanical cleaver, which is widely used because it can produce nicer and more repeatable cleaves. This cleaver is much easier to use thus the specific training is not essential. Just clamp the fiber in the correct position into the cleaver. Then, a force is applied and the fiber gives a nice break at the scribe.

Mechanical cleaver

Conclusion

Since fiber splicing requires mating two fiber ends together, any defect of the ends would impact the performance of fiber splicing. So in order to achieve good fiber optic splices or terminations, it is extremely important to cleave the fiber properly. And a good cleaver can help better finish the whole cleaving process.

Fundamentals of Power over Ethernet (PoE)

With the introduction of new Ethernet-enabled devices expanding geometrically, the need to power these devices from standard AC power outlets has become a limiting factor. IP telephones, wireless access points, IP cameras and device servers are examples of devices limited by the need to have an AC power outlet nearby to plug in a DC power adapter. At best, power supply installation and wiring adds labor and results in the mess of extra wiring; worst case, the lack of nearby AC power means devices cannot be installed where they are needed.

In response to this need, IEEE developed IEEE802.3af to standardize a system of supplying low voltage power to networked devices via the communications line. It is more commonly referred to as Power over Ethernet (POE). This article focus on introducing some fundamental elements about PoE.

Basic Concepts of PoE

PoE is defined across a single network link that includes three basic components. The first one is an equipment delivering power to the cable (often referred to as a PSE, which stands for power sourcing equipment). The second component is a device receiving power from the cable (also known as a powered device, or PD). The third is the cable itself.

Typical PDs include IP cameras, wireless access points, and the PSE would normally be a PoE switch or a midspan power injector, patched in to add PoE capability to a non-PoE network switch channel or similar. These two configurations are shown in the following picture.

PoE

Advantages of PoE

The most prominent advantages of PoE are time saving and cost effective. By reducing the time and expense of having electrical power cabling installed, network cables do not require a qualified electrician to fit them, thus it can be located anywhere. Besides, it has great flexibility. Without being tethered to an electrical outlet, the PDs (IP cameras, wireless access points) could be located wherever they are needed most. Safety is the third advantage. PoE delivery is intelligent and it is designed to protect network equipment from overload, or incorrect installation. Also it has reliability and scalability. PoE power comes from a central and universally compatible source, rather than a collection of distributed wall adapters. It can be backed-up by an uninterruptible power supply, or controlled to easily disable or reset devices.

Applications of PoE

The original PoE application is VoIP phones, which have a single connection to a wall socket, and can be remotely powered down, just like with the older analog systems. PoE could also be used in IP cameras. It is ubiquitous on networked surveillance cameras where it enables fast deployment and easy repositioning. Wifi and bluetooth APs and RFID (radio frequency identification devices) readers are commonly PoE-compatible, to allow remote location away from AC outlets, and relocation following site surveys.

How PoE Works

PoE is designed to operate over standard network cable: Cat 3, Cat 5, Cat 5e or Cat 6 (often collectively referred to as Cat 5), using conventional RJ45 connectors. The principles of carrying electrical power over Cat5 are of no difference to those of other power distribution systems, but as the power is being transferred over light-duty cable for long distances, the effects of the power loss and voltage drop become significant.

The arrangement and connection to the cabling used for PoE also differ slightly from conventional power wiring, in order to work around the existing standard for Ethernet data. Cat 5 network cables contain a bundle of eight wires, arranged as four twisted pairs shown in the following picture. In the most common type of Ethernet, 100BASE-T or Fast Ethernet, only two of the four pairs are used to carry data; each pair carrying a signal in one direction. These are known as the data pairs, and the remaining two are unused and are referred to as the spare pairs.

PoE working

Although each data signal can be carried within a single pair, PoE treats each pair of wires as a single conductor (a reason for this is that using both wires halves the overall resistance). As electrical current must flow in a loop, two pairs are required to allow power to be carried by the cable, and either the data or spare pairs can be used for this. The PD must be able to accept power from whichever pairs the PSE delivers it to.

Conclusion

PoE is a convenient and now ubiquitous method for delivering power to a wide variety of loads on standard Cat 5 Ethernet cables. It is no doubt that Power over Ethernet will become increasingly important in the near future.