August 2013 - Page 3 of 3 - Fiber Optical Networking

Fiber Optic Cables For Harsh Environment Applications

Fiber based systems offer apparent advantages over electrical methods in large plants and factories where the harsh environment threatens data reliability and security. Unlike copper cable, fiber optic cabling is resistant to electromagnetic interference (EMI), making it an ideal option for harsh environments involving high voltages or machinery with variable frequency drives, is a safe alternative to traditional wiring.

As you know, fiber optic cable consists of three parts: the core, the cladding, and the coating. The core transmits the light and has a high refractive index. The cladding contains the light within the core because its lower refractive index causes all the light rays to reflect back into the core. This “total internal reflection” or “fiber-optic effect” is the technology’s underlying principle. The coating, usually an acrylate polymer, protects the core/cladding assembly.

Optical fiber is typically made from high-purity silica glass. Plastic fiber of varying configurations is also available. But the attenuation of light energy can approach one thousand times that of glass fiber. The length and integrity of the transmission path and the core/cladding arrangement affect the bandwidth, or the frequency range that the optical fiber transmits. Fiber bandwidth is expressed in megahertz-kilometers (MHz-km).

Depending on the application, the distance involved, and the location, several types of cable configurations and connector types are available. Optical fiber is fragile and must be protected, mostly from mechanical stresses such as bending, crushing, thermal effects, and pulling during installation.

Tight Tube And Loose Tube Cable

A tight-tube (or tight-buffer) design has a PVC coating, which tightly bonds to the fiber, limiting movement. This cable type can have strength members, which you pull through conduit and cable trays. This design, however, has low crush resistance and is susceptible to deformation due to thermal expansion; thus, it is recommended for indoor use only.

A loose-tube design gives a fiber free movement. Each component of the Loose Tube Cables (the sheath or outer coating, the strength member, and the buffer tubes that carry the fibers) has different thermal characteristics. By allowing the fibers and the components surrounding them free movement, deformation is avoided.

Loose-tube construction has much better crush resistance than tight tube because of the buffer-tube protection of the fibers. Loose-tube cables have a strength member, which is used as the pulling member for conduit installation. Loose-tube cables are usually filled with a gel, which surrounds the fibers and increases protection from water. This also improves crash resistance because of the gel’s cushioning effect. You mostly use this cable type for outdoor applications, but you can also use it in harsh industrial environments. A drawback to this type of cable is the difficulty in handling individual fibers. The fiber coating does not have to be as thick as in tight-tube construction; thus, attaching connectors is difficult.

Remember that tight-tube construction does not allow for free movement and provides low protection against mechanical stress. It does, however, have a thick coating for ease of handling. Loose-tube construction, on the other hand, allows free movement and provides a good degree of protection.

Breakout Cable

Breakout cables are a hybrid solution. In a breakout cable, each fiber is treated as a separate unit, complete with a sheath and strength member. This design eliminates the need for a breakout kit, because the sheath lets you attach connectors easily.

Breakout Cable Fiber let fiber subunits move freely, and they protect each fiber by virtue of their thicker coating/strength member arrangement. Each fiber subunit is configured as a tight tube. Breakout cables also come equipped with a separate strength member just like the loose-tube design.

FiberStore harsh environment Fiber Cables is designed and manufactured with specialized components which provide improved performance and protection against damage, breakage, and performance limiting conditions that often exist in harsh environment applications. FiberStore has the resources, expertise, and experience to design, develop, manufacture, install, and maintain a product ideally suited for your exact application.

The Developing Of Ethernet Technologies

The most mature and common of the network applications is Ethernet. Over the past 25 years, despite stiff competition from more modern network architectures, Ethernet has flourished. In the past 10 years alone, Ethernet has been updated to support speeds of 100Mbps, 1Gbps (about 1000Mbps) and 10Gbps; currently 40 and 100 Gigabit Ethernet are being standardized in the IEEE 802.3b committee. Forty and 100 Gigabit Ethernet will be deployed over optical fiber for 100 meters or greater, and research is progressing to make it available over UTP for distances up to 10 meters.
Ethernet has evolved to the point that it can be used on a number of different cabling systems.

10Mbps Ethernet Systems

>>10Base-5: “Standard Ethernet Cable”
The earliest version of Ethernet ran on a rigid coaxial cable that was called Standard Ethernet cable, but was more commonly referred to as thicknet. While thicknet was difficult to work with (because it was not very flexible and was hard to install and connect nodes to), it was reliable and had a usable cable length of 500 meters. 10Base-5 systems can still be found in older installations, typically used as backbone cable, but virtually no reason exists for you to install a new 10Base-5 system today.>>10Base-T Ethernet

10Base-T : 10Mbps Ethernet over unshielded twisted-pair cable. Maximum cable length (network device to network card) is 100 meters.10Base-T (the T stands for twisted pair) Ethernet is less common today and has been overtaken by 100Base-T. Even though 10Base-T uses only two pairs of a four-pair cable, all eight pins should be connected properly in anticipation of future upgrades or other network architectures.

>>10Base-F Ethernet

Specifications for using Ethernet over Optical Fiber Cables existed back in the early 1980s. Originally, fiber-optic cable was simply used to connect repeaters whose separation exceeded the distance limitations of thicknet cable. The original specification was called Fiber-Optic Inter-Repeater

Link (FOIRL), which described linking two repeaters together with fiber-optic cable up to 1,000 meters (3,280´) in length. The cost of fiber-optic repeaters and fiber-optic cabling dropped greatly during the 1980s,and connecting individual computers directly to the hub via fiber-optic cable became more common.Originally, the FOIRL specification was not designed with individual computers in mind,so the IEEE developed a series of fiber-optic media specifications. These specifications are collectively known as 10Base-F. It is uncommon to use optical fiber at these slow speeds today. For historical purposes, the individual specifications for (and methods for implementing) 10Base-F Ethernet include the following:

>>10Base-2 Ethernet

10Base-2 is still an excellent way to connect a small number of computers together in a small physical area such as a home office, classroom, or

lab. The 10Base-2 Ethernet uses thin coaxial (RG-58/U or RG-58 A/U) to connect computers together. This thin coaxial cable is also called thinnet.

100Mbps Ethernet Systems

The 100Mbps version of 802.3 Ethernet specifies a number of different methods of cabling a Fast Ethernet system, including 100Base-TX, 100Base-T4, and 100Base-FX.

>>100Base-TX Ethernet

The 100Base-TX specification uses physical-media specifications developed by ANSI that were originally defined for FDDI (ANSI specification X3T9.5) and adapted for twisted-pair cabling. The 100Base-TX requires Category 5e or better cabling but uses only two of the four pairs. The eight-position modular jack (RJ-45) uses the same pin numbers as 10Base-T Ethernet.

>>The 100Base-T4 specification was developed as part of the 100Base-T specification so that existing Category 3–compliant systems could also support Fast Ethernet. The designers accomplish 100Mbps throughput on Category 3 cabling by using all four pairs of wire; 100Base-T4 requires

a minimu.m of Category 3 cable. The requirement can ease the migration path to 100Mbps technology.

>>100Base-FX Ethernet

Like its 100Base-TX copper cousin, 100Base-FX uses a physical-media specification developed by ANSI for FDDI. The 100Base-FX specification was developed to allow 100Mbps Ethernet to be used over fiber-optic cable. Although the cabling plant is wired in a star topology, 100Base-FX is

a bus architecture.

Gigabit Ethernet (1000Mbps)

1000Mbps Ethernet was supported only on fiber-optic cable. The IEEE 802.3z specification included support for three physical-media options (PHYs), each designed to support different distances and types of communications:

>>1000Base-SX
Targeted to intra-building backbones and horizontal cabling applications such as to workstations and other network nodes, 1000Base-SX is designed to work with multimode fiber-optic cable at the 850nm wavelength.

>>1000Base-LX
Designed to support backbone-type cabling such as inter-building campus backbones, 1000Base-LX is for Single-mode Fiber-optic Cable at 1310nm, though multimode fiber can be used for short inter-building backbones and intra-building cabling applications.

>>1000Base-CX
Designed to support interconnection of equipment clusters, this specification uses 150 ohm STP cabling similar to IBM Type 1 cabling over distances no greater than 25 meters. When cabling for Gigabit Ethernet using fiber, you should follow the ANSI/TIA-568-C standards for 62.5/125 micron or 50/125 micron multimode fiber for horizontal cabling and 8.3/125 micron single-mode fiber for backbone cabling. See Table 6 of Annex D in ANSI/TIA-568-C.0.

>>1000Base-T

Gigabit Ethernet over Category 5 or better UTP cable where the installation has passed performance tests specified by ANSI/TIA/EIA-568-B. Maximum distance is 100 meters from equipment outlet to switch. The IEEE designed 1000Base-T with the intention of supporting Gigabit Ethernet to the desktop. One of the primary design goals was to support the existing base of Category 5 cabling.

10 Gigabit Ethernet (10,000Mbps)

The IEEE approved the first Gigabit Ethernet specification in June, 2002: IEEE 802.3ae. It defines a version of Ethernet with a nominal data rate of 10 Gbit/s. Over the years the following 802.3 standards relating to 10GbE have been published: 802.3ae-2002 (fiber -SR, -LR, -ER, and -LX4 physical-media-dependent devices[PMDs]), 802.3ak-2004 (-CX4 copper twin-ax InfiniBand type cable), 802.3an-2006 (10GBASE-T copper twisted pair), 802.3ap-2007 (copper backplane -KR and-KX4 PMDs), and 802.3aq-2006 (-LRM over legacy multimode fiber -LRM PMD with electronic dispersion compensation [EDC]). The 802.3ae-2002 and 802.3ak-2004 amendments were consolidated into the IEEE 802.3-2005 standard. IEEE 802.3-2005 and the other amendments have been consolidated into IEEE Standard 802.3-2008. In the premises environment, 10 Gigabit Ethernet is mostly used in data center storage servers,high-performance servers, and in some cases for intra-building backbones. It can be used for connection directly to the desktop.

>>10GBASE-SR (Short Range)

10GBASE-SR (short range) uses 850nm VCSEL lasers over multimode fibers. Low-bandwidth 62.5/125 micron (OM1) and 50/125 micron (OM2) multimode fiber support limited distances of 33–82 meters. To support 300 meters, the fiber-optics industry developed a higher bandwidth version of 50/125 micron fiber optimized for use at 850nm.

>>10GBASE-LR (Long Range)

10GBASE-LR (long range) uses 1310nm lasers to transmit over single-mode fiber up to 10 kilometers. Fabry-Pérot lasers are commonly used in 10GBASE-LR optical modules. Fabry-Pérot lasers are more expensive than 850nm VCSELs because they require the precision and tolerances to focus on very small single-mode core diameters (8.3 microns). 10GBASE-LR ports are typically used for long-distance communications.

>>10GBASE-LX4

10GBASE-LX4 uses coarse wavelength division multiplexing (WDM) to support 300 meters over standard, low-bandwidth 62.5/125 micron (OM1) and 50/125 micron (OM2) multimode fiber cabling. This is achieved through the use of four separate laser sources operating at 3.125Gbps in the range of 1300nm on unique wavelengths. This standard also supports 10 kilometers over single-mode fiber. 10GBASE-LX4 is used to support both standard multimode and single-mode fiber with a single Optical Transceivers. When used with standard multimode fiber, an expensive Mode Conditioning Patch Cord is needed. The mode conditioning patch cord is a short length of single-mode fiber that connects to the multimode in such a way as to move the beam away from the central defect in legacy multimode fiber. Because 10GBASE-LX4 uses four lasers, it is more expensive and larger in size than 10GBASE-LR. To decrease the footprint of 10GBASE-LX4, a new module,10GBASE-LRM, was standardized in 2006.

>>10GBASE-LRM

10GBASE-LRM (long reach multimode) supports distances up to 220 meters on standard, lowbandwidth 62.5/125 micron (OM1) and 50/125 micron (OM2) using a 1310nm laser. Expensive mode conditioning patch cord may also be needed over standard fibers. 10GBASE-LRM does not reach quite as far as the older 10GBASE-LX4 standard. However, it is hoped that 10GBASE-LRM modules will be lower cost and lower power consumption than 10GBASE-LX4 modules. (It will still be more expensive than 10GBASE-SR.)

>>10GBASE-T

10GBASE-T supports 10Gbps over Category 6A UTP or Category 7 shielded (per ISO/IEC 11801Ed. 2) twisted-pair cables over distances of 100 meters. Category 5e is supported to much lower distances due to its limited bandwidth. Special care needs to be taken in installing Category 6A cables in order to minimize alien cross-talk on signal performance.

40 and 100 Gigabit Ethernet

The IEEE 802.3ba committee is standardizing 40 and 100 Gigabit Ethernet. This will be deployed over OM3 50/125 multimode optical fiber for 100–200 meters, and research is progressing to make it available over UTP for distances up to 10 meters.This could be the speed point at which there is mass conversion of copper to fiber-based systems.

References: FIBERSTORE PRODUCTS INFO

What are the Advantages and Disadvantages of Fiber Optic Cabling

Fiber optic cabling consists of strands of purified glass, or even plastic, rods that conduct specific wavelengths of light, analogous to the electrons carried along a Copper Ethernet Cable. However, light traveling through glass or plastic is not susceptible to the same problems that metal conductors are; The electromagnetic radiation that results from current traveling through a wire is not present in optical conductors, and optical conductors can be made much smaller than metal ones. Today, we’ll talk about the advantages and disadvantages of fiber optic cable.

Advantages and Disadvantages of Fiber Optic Cable

Everything has its own advantages and disadvantages. Learning the advantages and disadvantages of fiber optic cable, we may know how to select one when buying the cables.

Advantages

There are four advantages of fiber optic cabling, these advantages explain why fiber is becoming the preferred network cabling medium for high bandwidth, long-distance applications:

1. Immunity to Electromagnetic Interference (EMI)

All copper cable network media sharing a common problem: they are susceptible to electromagnetic interference (EMI), fiber optic cabling is immune to crosstalk because optical fiber does not conduct electricity and uses light signals in a glass fiber, rather than electrical signals along a metallic conductor to transmit data. So it cannot produce a magnetic field and thus is immune to EMI.

2. Higher Possible Data Rates

Because light is immune to interference, can be modulated at very high frequencies, and travels almost instantaneously to its destination, much higher data rates are possible with fiber optic cabling technologies than with traditional copper systems. Data rates far exceeding the gigabit per second (Gbps) range and higher are possible, and the latest IEEE standards body is working on 100Gbps fiber based applications over much longer distances than copper cabling. Multimode is preferred fiber optic type for 100-550 meters seen in LAN network, and since single mode fiber optic cables are capable of transmitting at these multi-gigabit data rates over very long distances, they are the preferred media for transcontinental and oceanic applications.

3. Longer Maximum Distances

Typical copper media data transmission by the distance limits the maximum length of less than 100 meters. Because they do not suffer from the electromagnetic interference problems of traditional copper cabling and because they do not use electrical signals that can dramatically reduce the long distance, single-mode fiber optic cables can span 75 kilometers (about 46.6 miles) without using signal-boosting repeaters.

4. Better Security

The Copper cable transmission media is susceptible to eavesdropping through taps. A tap (short for wiretap) is a device that punctures through the outer jacket of a copper cable and touches the inner conductor. The tap intercepts signals sent on a LAN and sends them to another (unwanted) location. Electromagnetic (EM) taps are similar devices, but rather than puncturing the cable,they use the cable’s magnetic fields, which are similar to the pattern of electrical signals. Because fiber optic cabling uses light instead of electrical signals, it is immune to most types of eavesdropping. Traditional taps won’t work because any intrusion on the cable will cause the light to be blocked and the connection simply won’t function. EM taps won’t work because no magnetic field is generated. Because of its immunity to traditional eavesdropping tactics, fiber optic cabling is used in networks that must remain secure, such as government and research networks.

Disadvantages

With all of its advantages, many people use fiber optic cabling. However, fiber optic cabling does have a couple of disadvantages:

1. Higher Cost

The higher cost of fiber optic cabling has little to do with the cable these days. Increases in available fiber optic cable manufacturing capacity have lowered cable prices to levels comparable to high end UTP on a per-foot basis, and the cables are no harder to pull. Ethernet hubs, switches, routers, NICs, and patch cords for UTP are very inexpensive. A high quality UTP-based 10/100/1000 auto-sensing Ethernet NIC for a PC can be purchased for less than $25. A fiber optic NIC for a PC costs at least four times as much. Similar price differences exist for hubs, routers, and switches. For an IT manager who has several hundred workstations to deploy and support, that translates to megabucks and keeps UTP a viable solution. The cost of network electronics keeps the total system cost of fiber-based networks higher than UTP, and ultimately, it is preventing a mass stampede to fiber-to-the-desk.

2. Installation

The other main disadvantage of fiber optic cabling is that it can be more difficult to install. Ethernet cable ends simply need a mechanical connection, and those connections don’t have to be perfect. Fiber optic cable can be much trickier to make connections for mainly because of the nature of the glass or plastic core of the fiber cable. When you cut or cleave (in fiber optic terms) the fiber, the unpolished end consists of an irregular finish of glass that diffuses the light signal and prevents it form guiding into the receiver correctly. The end of the fiber must be polished and a special polishing tools to make it perfectly flat so that the light will shine through correctly.

Conclusion

From the above, we have learnt the advantages and disadvantages of fiber optic cable. Knowing the advantages and disadvantages of fiber optic cable can help us to choose a suitable fiber cable. For more details about fiber cables, please visit FS.COM.

FiberStore Unveils MiniSAS SFFP-8088 Cables

Summary: The FiberStore MiniSAS SFFP-8088 to SFFP-8088 cables are advertised as ideal for dependable, reliable, and cost effective 6 Gb/s storage configurations for networks, servers, workstations and desktops.

FiberStore Co., Ltd has launched the MiniSAS SFFP-8088 to SFFP-8088 cables series which is designed for high performance networks, servers, workstations and desktops. This durable SAS cable features an External mini-SAS (SFF-8088) connector and an External mini-SAS (SFF-8088) connector, and supports data transfer rates of up to 6 Gbps.

As you might expect, the more lanes the faster speed, Mini-SAS is like traffic moving on 4 lanes on the highway instead of just 1 lane. Mini-SAS offers more “Lanes” for data to travel, providing the ability to reach higher speeds. Just like the SATA/eSATA interface, mini-SAS offers the convenience of a one cable connection. However, in a multi-drive SATA/eSATA solution which, only offers one lane for four drives to send/receive data on, mini-SAS provides four separate lanes so each drive can deliver its maximum capable data transfer rate.

Now you can use one or more mini-SAS equipped external storage enclosures like the OWC Mercury Rack Pro for greater speed, protection, or both compared to single channel multi-drive eSATA RAID or eSATA Port Multiplier solutions.

“This durable SAS cable features an SFF-8088 (external mini-SAS) connector, and supports data transfer rates of up to 6 Gbps.” comments Thorndike, FiberStore product manager. “Unlike SFF-8087, where the top cards often have four or six connectors, SFF-8088 usually comes with only one or two connectors per controller. This is because a single SFF-8088 connector on a SAS Expander-enabled controller can connect to a large SAS Expander-enable enclosure, which can then be daisy-chained.”

The SFF-8088 cables are currently available in 6 Gbs external or 3 Gbs internal and far-out assembly types. SFF-8088 with power are also in stock. Custom Mini-SAS cables are available in various lengths and other options. Contact for more information by calling 86-755-83003611, email sales@fiberstore.com, or visit www.fiberstore.com