Author Archives: Admin

Fiber Splitter for FTTH Applications

Passive optical network (PON) has been widely applied in the construction of FTTH (fiber to the home). With PON architecture, network service providers can send the signal to multiple users through a single optical fiber, which can help them save great costs. To build the PON architecture, optical fiber splitter is necessary.

What Is Fiber Splitter?

The fiber splitter is a passive component specially designed for PON networks. Fiber splitter is generally a two-way passive equipment with one or two input ports and several output ports (from 2 to 64). Fiber splitter is used to split the optical signal into several outputs by a certain ratio. If the ratio of a splitter is 1×8 , then the signal will be divided into 8 fiber optic lights by equal ratio and each beam is 1/8 of the original source. The splitter can be designed for a specific wavelength, or works with wavelengths (from 1260 nm to 1620 nm) commonly used in optical transmission. Since fiber splitter is a passive device, it can provide high reliability for FTTH network. Based on the production principle, fiber splitters include Planar Lightwave Circuit (PLC) and Fused Bionic Taper (FBT).

PLC splitters are produced by planar technology. PLC splitters use silica optical waveguide technology to distribute optical signals from central office to multiple premise locations. The output ports of PLC splitters can be at most 64. This type of splitters is mainly used for network with more users.

The Structure of PLC splitters

Internal Structure

The following figure shows a PLC splitter. The optical fiber is splitted into 32 outputs. PLC chip is made of silica glass embedded with optical waveguide. The waveguide has three branches of optical channels. When the light guided through the channels, it is equally divided into multiple lights (up to 64) and transmitted via output ports.

1x32-plc-splitter

Outside Configuration

Bare splitter is the basic component of PLC fiber splitter. For better protection of the fragile fiber and optimized use, PLC splitters are often equipped with loose tube, connector and covering box. PLC splitters are made in several different configurations, including ABS, LGX box, Mini Plug-in type, Tray type, 1U Rack mount, etc. For example, 1RU rack mount PLC splitter (as shown in the figure below) is designed for high density fiber optical distribution networks. It can provide super optical performance and fast installation. This splitter is preassembled and fibers are terminated with SC connectors. It’s ready for immediate installation.

rack-mount-plc-spllitter

FBT splitters are made by connecting the optical fibers at high temperature and pressure. When the fiber coats are melted and connected, fiber cores get close to each other. Then two or more optical fibers are bound together and put on a fused taper fiber device. Fibers are drawn out according to the output ratio from one single fiber as the input. FBT splitters are mostly used for passive networks where the split configuration is smaller.

PLC Splitters From FS.COM

Fiberstore offers a wide range of PLC splitters that can be configured with 1xN and 2xN. Our splitters are designed for different applications, configurations including LGX, ABS box with pigtail, bare, blockless, rack mount package and so on.

Port Configuration Package Style Fiber Diameter
(Input/output)
Connector (Input/output) Pigtail Length
1×2 Steel tube, bare fiber 250μm None 1.5m
1×4 Mini module 900μm SC APC/UPC 2.0m
1×8 Pigtailed ABS box 2.00mm LC APC/UPC 3.0m
1×16 Mini plugged-in 3.0mm FC APC/UPC Customized
1×32 LGX ST APC/UPC
1×64 Splice Tray Type Customized
2×16 Rack mount
Conclusion

Fiber splitter is an economical solution for PON architecture deployment in FTTH network. It can offer high performance and reliability against the harsh environment conditions. Besides, the small sized splitter is easy for installation and flexible for future network reconfiguration. Therefore, it’s a wise choice to use fiber splitter for building FTTH network.

Save Cost by Using BiDi Transceivers

As usual, optical transceivers such as SFP or SFP+ use two fibers to transmit data between switches. One fiber is used to transmit data to the network equipment and the other fiber is utilized to receive the data. As to the transceiver modules of high speed data rate like QSFP-40G-SR4 and QSFP-40G-ESR4, they need more fibers. Is there any technology allowing transceivers to transmit and receive through one single optical fiber or two fibers for QSFP+?

What Is BiDi Transceiver?

The answer is yes. And that kind of transceiver is called BiDi transceiver. Bidi (Bi–Directional) transceiver is also known as WDM transceiver, because it applies wavelength division multiplexing (WDM) couplers, also called diplexers, which combine and separate data transmitted over a single fiber based on the wavelengths of the light.

BiDi Transceiver Advantage

Compared with traditional transceiver modules, BiDi transceivers can cut your cost on fiber cabling infrastructure by requiring fewer fiber cables, reducing the number of fiber patch panel ports and saving fiber cable management space. Based on the obvious advantages, you should deploy BiDi transceivers in your network. Here will recommend you several kinds of BiDi transceivers of 1Gbps, 10Gbps and 40Gbps.

BiDi Transceiver Categories

BiDi SFP transceivers transmit and receive optical signal through a single fiber on the wavelengths of 1310 nm & 1490 nm, 1310 nm & 1550 nm, 1490nm & 1550 nm. BiDi SFPs include the supportable data rate of 100Mbps and 1000Mbps. Take the Cisco GLC-BX-U compatible 1000BASE-BX-U BiDi SFP as an example. The wavelengths of the BiDi SFP are 1310 nm and 1490 nm. It can support the link lengths of 10 km over LC simplex fiber patch cable. As shown in the following figure, a pair of Cisco GLC-BX-U compatible BiDi SFPs are linked via a single LC simplex fiber patch cable to build the direct connection of two Cisco Catalyst 4948E-F switches.

cisco-glc-bx-u

Bidi SFP+ transceiver is enhanced SFP designed to support 10Gbps data rate with link lengths up to 80 km over one fiber. It uses WDM technology sharing 1270 nm & 1330 nm. Take a look at the figure below. It’s about the direct connection for 10G BiDi SFP+ in room wiring. The two Cisco SFP-10G-BXU-I compatible 10GBASE-BX10-U SFP+ transceivers are plugged into Cisco Nexus 9396PX switches. The connection is achieved by using an LC simplex fiber patch cable. It’s a simplest and cost-effective way to build 10 Gigabit Ethernet connectivity for data center.

cisco-sfp-10g-bxu-i

BiDi QSFP+

40G BiDi QSFP+ transceiver is specially designed for high density data center. With QSFP+ BiDi transceivers, you can get 40Gbps network over 10Gbps cable. In this way, you don’t need to replace all 10G two-fiber patch cables with 8-fiber MTP/MPO patch cable if you need network upgrade. In Figure 3, we use Cisco QSFP-40G-SR-BD compatible 40GBASE-SR BiDi transceivers for the direct connection of two switches. Instead of applying 40G MTP patch cable, we can just plug the common LC-LC fiber patch cable into the transceivers to get 40Gbps network. It saves you lots of costs.

cisco-qsfp-40g-sr-bd

Warm Tips: When you buy a BiDi transceiver, you may notice wavelengths are labeled on the BiDi transceivers like 1270nm-TX/1330nm-RX or 1270nm-RX/1330nm-TX. From this perspective, you can see this type of transceivers should be used in matched pairs, with their diplexers tuned to match the expected wavelength of the transmitter and receiver that they will be transmitting data from or to.

Summary

BiDi transceivers may be more expensive than common transceiver modules, but they can save you the cost on fiber cables from the long run. Fiberstore offers BiDi transceivers of various data rates which are highly compatible with some famous brands. If you plan to purchase BiDi transceivers for building or upgrading your network, you can visit our site www.fs.com.

How Much Do You Know About SONET/SDH SFP+?

Before, Plesiochronous Digital Hierarchy (PDH) system was used to transport phone calls and data over the same fiber. Since phone calls and data traffic increase a lot, SONET/SDH are introduced to replace PDH system to transport the data without synchronization problems. As you can see, you always find SONET/SDH SFP+ in the market. Now, this article will give a brief analysis on SONET/SDH SFP+.

oc-192stm-64-sfp

SONET/SDH Interfaces Overview

SONET (Synchronous Optical Networking) and SDH (Synchronous Digital Hierarchy) are multiplexing protocols that transfer multiple digital bit streams over optical fiber with lasers or light-emitting diodes (LEDs). SONET and SDH are widely used methods today for very high speed transmission of voice and data signals across the numerous world-wide fiber-optic networks. SONET is the standard used in the United States and Canada, and SDH in the rest of the world. The two are largely equivalent. Although the SONET standards were developed before SDH, it is considered a variation of SDH because of SDH’s greater worldwide market penetration.

We often find SONET/SDH SFP transceiver like Cisco OC-3/STM-1 LR-1 SFP 1310nm 40km IND DOM. What does OC-3/STM-1 mean? OC-3c (Synchronous Transport Signal 3, concatenated) is the basic unit of SONET. Depending on the system, OC-3 is also known as STS-3 (when the signal is carried electrically). STM-1 (Synchronous Transport Module, level 1) is the basic unit of framing in SDH, which operates 155.52 Mbit/s. OC-3c and STM-1 have the same high-level functionality, frame size, and bit-rate.

SONET/SDH Data Rates
sonet-sdh-data-rates
SONET/SDH and 10 Gigabit Ethernet

10 Gigabit Ethernet (10GbE) means the Ethernet network runs at 10 Gigabit per second. The 10 Gigabit Ethernet defines two PHY (Physical Layer) types: a local area variant (LAN PHY) with a line rate of 10.3125 Gbit/s, and a wide area variant (WAN PHY) with the same line rate as OC-192/STM-64 (9,953,280 Kbit/s).

10GbE provided the potential for an Ethernet solution aligned with the data rate of OC-192 backbone. It’s the first time in Ethernet history that no additional speed matching equipment would be required to link with the WAN. A seamless end-to-end Ethernet network can be built with less money. But the question is how to balance the compatibility with the installed base of OC-192 equipment while still meeting the economic feasibility criteria of the P802.3ae Task Force in defining the 10GE WAN PHY. To solve this problem, an OC-192 frame format is provided to support only the SONET overhead features required for fault isolation. This simplification avoids unnecessary functions and cost.

In order to make sure that WAN PHY optics would benefit from the high volumes and low cost of Ethernet, the serial 1310 nm and 1550 nm transceiver modules were kept the same as the LAN PHY. Since the 1310 nm and 1550 nm transceiver modules are designed for up to 10km and 40 km links respectively, they will inter-operate with OC-192 transceiver modules for 1310 nm and 1550 nm over intermediate reach, respectively.

FS.COM SONET/SDH SFP+

Fiberstore offers OC-192/STM-64 SFP+ for short reach (SR-1, VSR) , intermediate reach (IR-2) and long reach (LR-2) applications (as shown in the following table). These SFP+ modules are compatible with the SONET/SDH and ATM standards. For more details, please visit www.fs.com or contact us via sales@fs.com.

Cat6 and Cat6a Copper Cable Differences

As the data speeds increase from Fast Ethernet to Gigabit Ethernet, cables for the network connection are also required to be improved. Cat6 and Cat6a are two kinds of copper cables for Gigabit Ethernet. “A” is short for “augmented”. Cat6a is an enhanced Cat6 cable. Do you know which you should use, Cat6 or Cat6a? Could these two categories replace each other? Now this article will tell some of their differences from several sides.

cat6-and-cat6a

Appearance

It’s not difficult to identify Cat6 and Cat6a cables from appearance. If you look at the jacket carefully, you will find the identifiers printed as Cat6 and Cat6a. You can also distinguish these two cables from thickness. Cat6a cables are much thicker than Cat6 cables.

Shielding

Copper cables have shielded twisted pair (STP) and unshielded twisted pair (UTP). STP cable means there is one or more additional jackets surrounding the inner twisted wire pairs for insulation. The shielding is beneficial for protecting cable from electromagnetic interference (EMI). (For more information about STP vs. UTP difference, you can refer to my blog “STP vs. UTP, Which One Is Better?” .) Cat6 and Cat6a cables also include these two types. Though shielded Cat6 cables are available in the market, unshielded versions are easier to get. On the contrary, shielded Cat6a cables are more common.

Transmission Distance

Cat6 cable can support the transmission distance up to 100 meters at the data rate of 10, 100, 1000 Mbps. But it can support only 55 meters at the speed of 10 Gbps when crosstalk is in an ideal situation. What’s worse, the transmission distance can only reach 33 meters when the crosstalk is high. So the lengths of Cat6 cables are influenced by the network speed and crosstalk conditions. While Cat6a cables can support the distance over 100 meters at the speed of 10 Gbps.

Cost

Take Fiberstore as an example, the average cost of 1m Cat6 cable is about 1.00 US$ and more than 3.00 US$ for 1m Cat6a cable (cables maybe more expensive on other sites.). The more cables you purchase, the bigger the price difference will be. And the price difference is not only caused by the cable. Other matched connection components should also be considered.

Durability

As mentioned above, Cat6a cable is thicker and heavier than Cat6 cable. Cable trays can not hold as many Cat6a cables as Cat6 cables. When laying cables on the trays, you should better not bend cables too much as this can damage the wiring and influence network performance. The minimum radius that a cable can be bent without damaging is called the bend radius. The lower the bend radius, the more you can bend the cable. As Cat6a cable is bulkier than Cat6, Cat6a cable has a larger bend radius than Cat6 cable.

Which One Should You Buy?

Although Cat5e cable can meet the current needs in your home or office, higher bandwidth will be required in the near future. So you should upgrade your network with Cat6 or Cat6a cables which can provide greater bandwidth. At that time, you need to figure out which one to buy. If you install cables in a small room or business offices where cables might get close to one another, then Cat6a is better than Cat6 due to the alien crosstalk. Cat6 cables especially the unshielded cables, are much more prone to alien crosstalk than Cat6a, which uses superior insulation to protect its wiring.

Summary

From this article, you can make a clear identification of Cat6 and Cat6a cables. When you plan to purchase cables, you need to consider their differences like shielding, transmission distance, cost, durability, etc. Hope you can choose the suitable cable and build a high performance network.

Comparison Between FBT and PLC Splitters

Enabling a single fiber interface to be shared among many subscribers, fiber optic splitters play an increasingly significant role in many of today’s optical networks. From FTTx systems to traditional optical networks, splitters provide capabilities that help users maximize the functionality of optical network circuits. In this article, I’d like to give a short introduction of fiber optic splitters.

Overview of FBT and PLC Splitters

In simple terms, a fiber optical splitter is a passive optical device that can split, or separate beams into two or more light beams. Based on the configuration of the splitter, these beams may or may not have the equal optical power as the original beam. By means of different constructions, the outputs of a splitter can have varying degrees of throughput, which is highly beneficial when designing optical networks.

fiber optic splitter

Now although technology continually evolves, and there are a variety of existing splitters in the market, the most two common types of fiber optic splitter are: fused biconic tapered splitter (FBT Splitter) and planar lightwave circuit splitter (PLC Splitter).

FBT is the traditional technology in which two fibers are placed closely together and fused together by applying heat while the assembly is being elongated and tapered. As the technology continues developing, the quality of FBT splitter is very good and they can be applied in a cost-effective way. Now FBT is designed to split power in optical telecommunication and widely used in passive networks, especially where the split configuration is relatively small.

FBT splitter.jpg

PLC splitter is a better choice for application where large split configurations are required. It uses an optical splitter chip to divide the incoming signal into multiple outputs. PLC splitter composes of three layers: a substrate, a waveguide, and a lid. The waveguide plays a key role in the splittering process which allows for passing specific percentages of light. Therefore, PLC splitters offer very accurate splits and a low loss. What’s more, PLC splitters have several types such as bare PLC splitter, blockless PLC splitters, fanout PLC splitter, mini-plug in type PLC splitter, etc.

PLC splitter.jpg

With the growth of FTTx worldwide, in order to serve mass subscribers, the demand for large split configurations in these networks has also grown quickly. Because of the performance benefits and overall low cost, PLC splitters are now the better solutions for these types of applications.

FBT Splitter vs. PLC Splitter

In optical networks, signals need to be splitted somewhere in order to serve for different customers. Splitter technology has made great progress in the past few years by introducing PLC splitter. However, being similar in size and outer appearance, the two types of splitter still have many differences. Here is a brief comparison of them.

Materials

FBT splitter is made out of materials that are easily available, for example, steel, fiber, hot dorm and others. All of these materials are cheap, which determines the low cost of the device itself. The technology of the device manufacturing is also relatively simple, which leads to its low prices as well. Compared with FBT splitters, the technology of PLC splitter is more complicated and expensive. It uses semiconductor technology production. Hence it is more difficult to manufacture PLC splitters. And the price of the device is higher.

Operating Wavelength

FBT splitters only supports three wavelengths: 850 nm, 1310 nm and 1550 nm, which makes its inability to works on other wavelengths. While PLC splitter can support wavelength from 1260 to 1650 nm. The adjustable rang of wavelength allows PLC splitter more wide applications.

Split Ratio

The split ratio of FBT splitter is up to 1:32, while the ratio PLC splitter goes up to 64, providing a high reliability. Furthermore, the signal in PlC splitter can be split equally due to technology implemented.

Temperature

In certain areas, temperature can be a crucial factor that affects the performance of optical components. Therefore, sometimes devices with good cold resistance is also vital. FBT splitter can work stable under the temperature of -5 to 75℃. PLC splitter can work at a wider temperature range of -40 to 85 ℃, providing relatively good performance in the areas of extreme climate.

Apart from the differences mentioned above, there are still other differences between FBT splitter and PLC splitter. For example, compared with FBT splitter, the size of PLC splitter is more compact. Hence, PLC spitter is more suitable for density applications.

Conclusion

In conclusion, this article introduce the fiber optical splitters and the differences between FBT splitter and PLC splitter. It’s significant to choose the most suitable splitters for your networks. There are a variety of splitters avaible in Fiberstore. If you want to know detailed information, please visit FS.COM.

Guide to Choose the Right Fiber Optic Patch Cable

Now with the fiber optic cable being widely used in a variety of industries and places, the requests for fiber patch are being elaborated. Fiber patch cables are being required to be improved and provided more possibilities to satisfy various application environments. Actually, many special fiber patch cables have been created to answer the market demand. But do you know how to choose right fiber optic patch cable for our network system? The following passages may give you a clear guideline to choose the suitable patch cables.

Why You Need Different Fiber Optic Patch Cables?

Fiber optic patch cable, some times also called fiber optic jumper cable, are terminated with fiber optic connectors on both ends. Due to the fact that fiber patch cable can carry more data efficiently, they play an important role in telecommunication and computer networking. And they are also used in numbers of places. Therefore, when you choose fiber patch cables, the first thing you need to know is the environment that the patch cable will be used. Indoor or outdoor? In the air or buried underground? Different environments have different requirements for cables. Let’s take armored fiber patch cable for example. Armored fiber patch cable, wrapped a layer of protective “armor” outside of the fiber optic cable, is generally adopted in direct buried outside plant applications where a rugged cable is needed for rodent resistance.

fiber optic patch cable

What You Should Concern to Choose the Fiber Optic Patch Cable?
Single-mode vs Multimode

Single-mode fiber patch cable uses 9/125um glass fiber and multimode fiber patch cable uses 50/125um or 62.5/125um glass fiber. Generally, single-mode fiber patch cables are the best choice for transmitting data over long distances. They are usually used for connections over large areas, such as college campuses and cable television networks. And most single-mode cabling is color-coded yellow. Multmode fiber patch cables are usually used in short distances. They are typically used for data and audio/visual applications in local-area networks and connections within buildings. Multimode cables are generally color-coded orange or aqua.

single-mode and multimode patch cbale

Simplex vs Duplex

Simplex Fiber optic cable means the cable composes of only one fiber, then a duplex patch cable consists of two fibers. Therefore, simplex fiber optic cable is common used in a system where only one-way data transfers. And duplex fiber optic cable is applied to where requires simultaneous, bi-directional data transfer.

simplex and duplex patch cable

Connector Types

On both ends of the fiber optic patch cable are terminated with a fiber optic connector (LC/SC/ST/FC/MPO/MTP). With the rapid development of optical fiber telecommunication, many different types of fiber connectors are available. They share similar design characteristics. Different connector is used to plug into different device. If ports on the both ends devices are the same, the patch cables such as LC-LC/SC-SC/MPO-MPO can be used; if you want to connect different ports type devices, LC-SC, LC-FC and LC-ST patch cables may meet your demand.

connector types.jpg

Polishing Types

It’s known to us that whenever a connector is installed on the end of fiber, loss cannot be avoided. Some of this light loss is reflected directly back down the fiber towards the light source that generated it. These back reflections will damage the laser light sources and also disrupt the transmitted signal. In order to optimize transmitting performance and ensure the proper optical propagation, the end of the fiber must be properly polished to minimize loss. Generally, there are two common polishing types: UPC and APC. And the loss of APC connector is lower than UPC connectors. So the optical performance of APC connector is better than UPC connectors.

UPC-APC-fiber-optic-patch-cable.jpg

Cable Jacket

The cable jacket is to provide strength, integrity, and overall protection of the fiber member. When choose one kind of fiber optic cables, the environment that the cables be used should be taken into consideration. Usually there are three types of jacket: PVC, LSZH and OFNP. Which one you choose depends on where you use the cables. Here are their features.

  • PVC cable resistant to oxidation, it is commonly used for horizontal runs from the wiring center.
  • LSZH cable has a special flame-retardant coating and it is used between floors in a building.
  • OFNP cable has fire-resistance and low smoke production characteristics. It usually works for vertical runs between floors.
Conclusion

In summary, there are many factors which may affect your choices of fiber optic patch cable. So it’s important to make sense which kind of patch cable can really meet your requirements. Fiberstore can provide all kinds of fiber optic patch cables to satisfy your needs!

Things You Need to Know Before Deploying 10 Gigabit Ethernet Network

Since the establishment of 10 Gigabit Ethernet, it has been employed by large amount of enterprises in their corporate backbones, data centers, and server farms to support high-bandwidth applications. But how to achieve a reliable, stable and cost-effective 10Gbps network? There are ten things you should know before doing the deployment.

More Efficient for the Server Edge

Many organizations try to optimize their data centers by seeking server virtualization which supports several applications and operating systems on a single server by defining multiple virtual machines on the server. Because of this, the organizations can reduce server inventory, better utilize servers, and mange resources more efficiently. Server virtualization relies heavily on networking and storage. Virtual machines require lot of storage. The network connectivity between servers and storage must be fast enough to avoid bottlenecks. And 10GbE can provide the fast connectivity for virtualized environments.

More Cost-effective for SAN

There are three types of storage in a network: direct-attached storage, network attached storage, and SAN. Among them, SAN is the most flexible and scalable solution for data center and high-density applications. But it costs much and needs special trainees for installing and maintaining the Fibre Channel interconnect fabric.

The internet small computer system interface (iSCSI) makes 10 Gigabit Ethernet an attractive interconnect fabric for SAN applications. iSCSI allows 10 Gigabit Ethernet infrastructure to be used as a SAN fabric which is more favorable compared with Fibre Channel. Because it can reduce equipment and management costs, enhance server management, improve disaster recovery and deliver excellent performance.

Reducing Bottlenecks for the Aggregation Layer

Today, traffic at the edge of the network has increased dramatically. Gigabit Ethernet to the desktop has become more popular since it becomes less expensive. More people adopt Gigabit Ethernet to the desktop, which increases the oversubscription ratios of the rest of the network. And that brings the bottleneck between large amounts of Gigabit traffic at the edge of the network and the aggregation layer or core.

10 Gigabit Ethernet allows the aggregation layer to scale to meet the increasing demands of users and applications. It can well solve the bottleneck for its three advantages. First, 10 Gigabit Ethernet link uses fewer fiber stands compared with Gigabit Ethernet aggregation. Second, 10 Gigabit Ethernet can support multi Gigabit streams. Third, 10 Gigabit Ethernet provides greater scalability, bringing a future-proof network.

Fiber Cabling Choices

To realize 10 Gigabit Ethernet network deployment, three important factors should be considered, including the type of fiber cable (MMF of MF), the type of 10 Gigabit Ethernet physical interface and optics module (XENPAK, X2, XFP and SFP+).

Cable Types Interface Max Distance
MMF (OM1/OM2/OM3) 10GBASE-SR 300 m
10GBASE-LRM 220 m
10GBASE-ER 40 km
SMF (9/125um fiber) 10GBASE-LR 10 km
10GBASE-ZR 80 km

Form factor options are interoperable when 10 Gigabit Ethernet physical interface type is the same on both ends of the fiber link. For example, 10GBASE-SR XFP on the left can be linked with one 10GBASE-SR SFP+ on the right. But 10GBASE-SR SFP+ can’t connect to one 10GBASE-LRM SFP+ at the other end of the link.

Copper Cabling Solutions

As copper cabling standards becomes mature, the copper cabling solutions for 10GbE is becoming common. Copper cabling is suitable for short distance connection. The are three different copper cabling solutions for 10 Gigabit Ethernet: 10GBASE-CX4, SFP+ DAC (direct attach cable) and 10GBASE-T.

10GBASE-CX4 is the first 10 Gigabit Ethernet standard. It’s economical and allowed for very low latency. But it’s a too large form factor for high density port counts in aggregation switches.

10G SFP+ DAC is a new copper solution for 10 Gigabit Ethernet. It has become the main choice for servers and storage devices in a rack because of its low latency, small connector and reasonable cost. It’s the best choice for short 10 Gigabit Ethernet network connection.

10GBASE-T runs 10G Ethernet over Cat6a and Cat7 up to 100 m. But this standard is not very popular since it needs technology improvements to reduce its cost, power consumption, and latency.

For Top of Rack Applications

A top-of-rack (ToR) switch is a switch with a low number of ports that sits at the very top or in the middle of a 19’’ telco rack in data centers. A ToR switch provides a simple, low-cost way to easily add more capacity to a network. It connects several servers and other network components such as storage together in a single rack.

ToR switch uses SFP+ to provide 10G network in an efficient 1U form factor. DAC makes rack cabling and termination easier. Each server and network storage device can be directly connected to the ToR switch, eliminating the need for intermediate patch panels. DAC is flexible for vertical cabling management within the rack architecture. And the cabling outside the rack, the ToR switch uplink connection to the aggregation layer, simplifies moving racks.

The following figure shows a 10 Gigabit Ethernet ToR switching solution for servers and network storage. Because the servers are virtualized, so the active-active server team can be distributed across two stacked witches. This can ensure physical redundancy for the servers while connected to the same logical switch. What’s more, failover protection can be offered if one physical link goes down.

10G-ToR

Conclusion

10 Gigabit Ethernet network is not the fastest but quite enough for common use in our daily life. So you should better read this article before you do the deployment. Besides, FS.COM provides both fiber and copper cabling solutions for 10G network. For more details, please visit www.fs.com.

The New 10G Multimode Optical Solution – 10GBASE-LRM

10 Gigabit Ethernet has been applied for a long time in data centers and enterprise LANs. For 10G Ethernet connection, there are both single-mode and multimode solutions. First let’s see the original multimode solutions and supportable distances for 10G Ethernet.

10G-multimode solution-supportable-distance

10GBASE-S operates at 850nm wavelength. It can support up to 300m distance over laser-optimized OM3. This makes it a popular standard for data centers and cooperate backbones. For the conventional OM1 and OM2 which are not optimized for laser transmission, the furthest supportable distance is 33 m and 82 m. So these two solutions are only used in equipment rooms or small data centers.

10GBASE-LX4 was specified to support 300 m over three cable types. So it relies on coarse wavelength division multiplexing (CWDM) which is more complex and expensive technology. 10GBASE-LX4 operates at 1300nm wavelength and that requires additional cost on mode-conditioning patch cords (MCPCs).

The high cost and relatively slow adoption of 10GBASE-LX4 drive the development of a new standard—10GBASE-LRM. 10GBASE-LRM is developed to offer a longer reach for conventional fiber cables at a lower cost and smaller size than 10GBASE-LX4. The following will talk about 10GBASE-LRM from three sides.

Transmission Distance

On condition the supporting distance, 10GBASE-LRM can only support 220 m. It’s suitable for LAN networks within buildings. But a cabling survey provides that for 10G network, the distance is not able to address 30% of in-building channels.

Electronic Dispersion Compensation

The key to the long reach of 10GBASE-LRM on conventional multimode fiber is electronic dispersion compensation (EDC). EDC is deployed as an integrated circuit that acts like a complex filter on the received signal from the optical fiber. The purpose is to extend the maximum supportable distance. 10GBASE-LRM applies EDC technology and is therefore independent of the optical wavelength. 10GBASE-LRM operates at 1300 nm.

EDC chips is added to a linear detector in the receiver. As an additional component, it increases cost, consumes power and wastes heat. It can only work as intended in conjunction with a linear detector and amplifier. Because the EDC device must operate on a faithful analog rendition of the optical waveform in the fiber. For 10GBASE-LRM, to reproduce the optical waveform with precision, extra requirements and cost on the receiver design are needed.

Multiple Transmit Launch Conditions

In order to improve the chances of operating at a higher bandwidth, 10GBASE-LRM relies on multiple transmit launch conditions.

One launch is achieved by using mode-conditioning patch cord. The other launch is produced using a regular multimode patch cord. Through the two launches, different modes can be achieved and a favorable operating condition can be easily found.

There are four possible patch cord combinations at both ends of the channel. The preferred launch uses MCPCs on both ends. This process requires a test for link stability for each configuration. The user should shake and bend the patch cord at the transmit end while observing channel health indicators at the receive end. The shaking and bending of the cords causes changes to the received waveform which the receiver must tolerate in normal operation. If there were transmission errors, then users should change another launch. The errors indicate that the channel is operating near or beyond the limit of the receiver’s capability and the link may fail in operation.

launch-conditions-for-10gbase-lrm

However, the 10GBASE-LRM standard’s committee refuse to implement this channel test. So the burden of the shaking and bending lies on the users. It’s not good for the popularity of 10GBASE-LRM.

Comparison of Several 10G Transceivers Cost

The following will compare the cost of 10G transceivers from several sides, including laser, receiver, package and cords.

Laser: 10GBASE-LRM uses 1310nm fabry perot lasers, which cost fewer than 10GBASE-L’s and 10GBASE-LX4 DFB lasers, but more than 10GBASE-S’s 850nm VCSELs. 10GBASE-LRM requires tighter transmitter waveform control to limit the transmit waveform dispersion penalty that EDC can’t compensate. Thus, it reduces transmitter yields and increases cost.

Receiver: 10GBASE-LRM adds EDC chip cost to receiver and needs a linear detector and amplifier instead of other cheap digital equipment.

Package: 10GBASE-LRM requires a smaller package than 10GBASE-LX4. However, not like 10GBASE-S, 10GBASE-LRM requires higher-cost single-mode transmitter alignment for compatibility with mode conditioning patch cords.

Cords: 10GBASE-LRM needs mode conditioning patch cords for reliable link operation. And the cost is much higher than regular SMF or MMF fiber optic patch cords.

Through the comparison among these 10G optical transceivers, you may find which one costs fewer. 10GBASE-LRM transceiver is cheaper than 10GBASE-LX4, more expensive than 10GBASE-L and 10GBASE-S transceivers.

Conclusion

10GBASE-LRM is a multimode solution for 10 Gigabit Ethernet. Based on the above content, 10GBASE-LRM has some advantages over 10GBASE-LX4. It offers lower cost and smaller package. But the distance and reliability are not very ideal. Compared with 10GBASE-S, 10GBASE-LRM is not so good as to the cost, simplicity, reliability and distance capability. FS.COM provides various types of cost-effective 10GBASE transceivers, such as 10GBASE-LR, 10GBASE-SR, 10GBASE-ER, etc. Other compatible brands like Cisco, Juniper, Arista, Brocade are also available. Among so many choices, you must choose the most suitable solution for your network connection.

QSFP+ Direct Attach Copper Cables for EX Series Switches

Quad small form-factor pluggable plus (QSFP+) direct attach copper (DAC) cables are suitable for in-rack connections between QSFP+ ports of EX Series switches. They are suitable for short distances of up to 10 meters, making them ideal for highly cost-effective networking connectivity within a rack and between adjacent racks. This article will introduce EX Series switches and QSFP+ DAC for EX Series switches.

Introduction to EX Series Switches

EX Series switches deliver scalable port densities and carrier-proven high availability features that consolidate legacy switch layers, helping to reduce capital and operational expenses and advance the economics of networking. For example, the EX 4200 series Ethernet switches with Virtual-Chassis technology, deliver the same Gigabit Ethernet (GbE) and 10GbE port densities as traditional chassis-based switches, but at one-eighth the footprint and less than one third the cost. The EX Series switches are right-sized for campus, data center and remote office environments and feature many of the same carrier-class hardware and software architectures found in core routers that were purpose-built to support the convergence of data, voice, and video onto a single always-on network.

EX 4200 Series switch

By alleviating the cost, complexity and risk associated with legacy switch infrastructures, the EX Series switches enable high-performance businesses to deploy a high-performance network infrastructure based on three key tenets – operational simplicity, carrier-class reliability, and integration and consolidation – to enable ubiquitous access to strategic assets, reduce network downtime and enhance overall security to shared assets across the extended enterprise.

QSFP+ DAC Specifications

QSFP+ direct attach copper (DAC) cable is hot-removable and hot-insertable. QSFP+ DAC mainly has two kinds. One is a cable that connects directly into two QSFP+ modules, one at each end of the cable. The cables use integrated duplex serial data links for bidirectional communication and are designed for data rates up to 40 Gbps. The other is a breakout cable consisting of a QSFP+ transceiver on one end and four SFP+ transceivers on the other end. The QSFP+ transceiver connects directly into the QSFP+ access port on the QFX Series device. The cables use high-performance integrated duplex serial data links for bidirectional communication on four links simultaneously. The SFP+ links are designed for data rates up to 10 Gbps each.

The following table describes the software support for QSFP+ passive DAC cable lengths on EX Series switches for Junos OS releases.

Switch

Software Support Added

DAC Model Number

EX44300 switches

Junos OS for EX Series switches, Release 13.2X51-D15 or later

EX4300 switches

  • EX4300-24T, EX4300-24P, EX4300-48T, EX4300-48T-AFI, EX4300-48P,
    EX4300-48T-DC, and EX4300-48T-DC-AF switches—Junos OS for EX Series switches, Release 13.2X50-D10 or later
  • EX4300-32F switches—Junos OS for EX Series switches, Release 13.2X51-D15 or later
  • EX4300-24T-S, EX4300-24P-S, EX4300-32F-S, EX4300-48T-S,
    and EX4300-48P-S switches—Junos OS for EX Series switches, Release 13.2X51-D26 or later
  • EX-QSFP-40GE-DAC-50CM
  • QFX-QSFP-DAC-1M
  • QFX-QSFP-DAC-3M
  • JNP-QSFP-DAC-5M

EX4550 switches

  • EX4550-32T-AFI, EX4550-32T-AFO, EX4550-32T-DC-AFI, EX4550-32T-DC-AFO,
    EX4550-32F-AFI, EX4550-32F-AFO, EX4550-32F-DC-AFI, and EX4550-32F-DC-AFO switches—Junos OS for
    EX Series switches, Release 13.2X50-D10 or later
  • EX4550-32F-S switches—Junos OS for EX Series switches, Release 12.3R5 or later
  • EX-QSFP-40GE-DAC-50CM
  • QFX-QSFP-DAC-1M
  • QFX-QSFP-DAC-3M
  • JNP-QSFP-DAC-5M
Conclusion

QSFP+ direct attach copper cables can provide cost-effective and reliable 40G speed connections for EX Series switches with distances reaching up to 10 meters. As the leading fiber optical manufacturer in China, FS.COM offers a wide selection of QSFP+ DAC with low cost but high performance. In addition, 10G SFP+ to SFP+ DAC (eg. HP JD096C), 25G SFP28 to SFP28 DAC, 40G QSFP+ to 4 XFP DAC, 100G QSFP28 to QSFP28 DAC, 100G QSFP28 to 4 SFP28 DAC are also available for your choice. All these DACs are with 100% compatibility and can be customized according to your special requirements.

OTDR Selection Guide

As the use of fiber in premise networks continues to grow, so do the requirements for testing and certifying it. An optical time-domain reflectometer (OTDR) is an electronic-optical instrument used to characterize optical fibers. It locates defects and faults, and determines the amount of signal loss at any point in an optical fiber by using the effects of Rayleigh scattering and Fresnel reflection. By sending a pulse of light into a fiber and measuring the travel time (“time domain”) and strength of its reflections (“reflectometer”) from points inside the fiber, it produces a characteristic trace, or profile, of the length vs. returned signal level on a display screen (as shown in the following picture). This article will describe the key specifications that should be considered when choosing an OTDR.

OTDR

When choosing an OTDR, it is important to select the specific OTDR performance and features according to the required specifications listed below.

Dynamic Range

The dynamic range of an OTDR determines how long of a fiber can be measured. The total optical loss that an OTDR can analyze is mainly determined by the dynamic range. The dynamic range affects the accuracy of the link loss, attenuation and far-end connector losses. Thus, having sufficient dynamic range is really important. The manufacturers specify dynamic range in different way. The higher the dynamic range, the longer the distance an OTDR can analyze.

Dead Zones

Dead zone refers to the space on a fiber trace following a Fresnel reflection in which the high return level of the reflection covers up the lower level of backscatter. To specify an OTDR’s performance, it is important to analyze the dead zone and ensure the whole link is measured. Dead zones are characterized as an event dead zone and an attenuation dead zone. Event dead zone refers to the minimum distance required for consecutive reflective events to be “resolved” (for example, to be differentiated from each other). Attenuation dead zone refers to the minimum distance required, after a reflective event, for the OTDR to measure a reflective or non-reflective event loss.

Resolution

There are two resolution specifications: loss (level), and spatial (distance). Loss resolution is the ability of the sensor to distinguish between levels of power it receives. When the laser pulse gets farther out in the fiber, the corresponding backscatter signal gets weaker and the difference between backscatter levels from two adjacent measurement points becomes larger. Spatial resolution is how close the individual data points that make up a trace are spaced in time (and corresponding distance). The OTDR controller samples the sensor at regular time intervals to get the data points. If it takes readings from the sensor very frequently, then the data points will be spaced close together and the OTDR can detect events in the fiber that are closely spaced.

Pass/Fail Thresholds

This is an important feature because a great deal of time can be saved in the analysis of OTDR traces if the user is able to set pass/fail thresholds for parameters of interest (such as splice loss or connector reflection). These thresholds highlight parameters that have exceeded a warning or fail limit set by the user and, when used in conjunction with reporting software, it can rapidly provide re-work sheets for installation/commissioning engineers.

Post-Processing and Reporting

Report generation could be another major time saver. For example, some OTDRs with specialized post-processing software allow fast and easy report generation, which might reduce the post-processing time up to 90 percent. These reports also include bidirectional analyses of OTDR traces and summary reports for high-fiber-count cables.

Your Applications and Users

Some OTDRs are designed to test long distance optical fibers and some others to test short distance optical fibers. For example, if you are to test premises fiber networks where short distance optical fibers are installed, OTDRs designed for testing long distance optical fibers are not suitable. Besides, knowing your users and the time it will cost is also necessary. Because some types of OTDRs are easy to use and some others are complicated to set up.

When selecting an OTDR, you’re supposed to take all the above factors into consideration. Fiberstore supplies a wide range of OTDRs available with various fiber types and wavelengths (including single-mode fiber, multi-mode fiber, 1310nm, 1550 nm, 1625 nm, etc). They also supply OTDRs of famous brands, such as JDSU MTS series, EXFO FTB series, YOKOGAWA AQ series and so on. OEM portable and handheld OTDRs are available as well.