Frequently Asked Questions (FAQs)

1. My department needs to deal with a lot of moves, adds and changes (MACs). How can I accomplish these cost-effectively and still use fiber?
2. Does it cost more to install fiber cable than UTP cable?
3. How can I effectively incorporate VOIP into an all- fiber network?
4. Is a patch panel required in the TR?
5. In your cost model, environmental controls are a significant expense. Are they really necessary?
6. Is fiber more difficult to install than copper?
7. Is it easy to test fiber links?
8. Are there any applications that require fiber?
9. I have an existing copper infrastructure, what's the most cost-effective way to upgrade to fiber?
10. What's the difference between 62.5 micron and 50 micron fibers?
11. Why do I need to install optical fiber?
12. I already have TRs in my building, is Centralized Cabling appropriate for an upgrade?
13. Aren't fiber solutions more expensive than UTP copper solutions?
14. Do media converters add a point of failure to the network? Why would I want to use them?
15. What are SFF connectors, and why should I consider them?
16. Since fiber is made of glass, will it survive harsh conditions?

My department needs to deal with a lot of moves, adds and changes (MACs). How can I accomplish these cost-effectively and still use fiber?^top

You should consider using Fiber to the Telecommunications Enclosure (FTTE). In this architecture, electronics are typically centralized in a singe Telecommunications Room, and then the fiber is run to a Telecommunications Enclosure (TE). The final distribution from the TE can be by wireless, copper or fiber. This architecture can help you leverage the benefits afforded by fiber by moving closer to the user, while at the same time providing extreme flexibility.

Does it cost more to install fiber cable than UTP cable?^top

It shouldn't. But we have heard that in some parts of the country, installers are asking for premiums of up to 30% more to install fiber cable! If you receive quotes that show fiber installation to be significantly more than UTP copper, we encourage you to refer to our cost model, which shows that fiber cable installation can cost the same, or even less than copper. Now that fiber has been installed in the backbone for more than a decade, most installers have the training and comfort level with fiber cable to make installation cost efficient.

How can I effectively incorporate VOIP into an all- fiber network?^top

There are several solutions for this application. The main issue is how you power your talk sets. There are a number of manufacturers that sell talk sets or IP phones. These phones come in different styles with a variety of features. Some are traditional desktop phones, which you plug into an AC outlet and connect via an RJ style patch cord to the network. If fiber is run to the work area, you add a media converter in the work area to change from fiber back to copper for the phone. Another option is to purchase a headset that attaches to the desktop via a USB port or serial port. Typically, with the purchase of the headsets all the necessary software to use the headset to access the VOIP service is included. The headsets utilizing USB ports bypass the desktop's soundcard and give good quality sound. For the headsets that utilize serial ports, you may need an additional module. There may be IP desktop phones that are available with a fiber interface that is powered by an AC adapter and plugged into conventional wall outlet. Another approach is to deploy fiber to the TE and then use a copper cable from the zone to the desk for the talk set.

Is a patch panel required in the TR?^top

Not necessarily. Eliminating the fiber patch panel is consistent with TIA/EIA 568 B. When using this configuration, all rerouting is done at the Central Distribution Panel (CDF). Keep in mind that according to the TIA/EIA 568-B.1 Annex A if the run is less than or equal to 90m a pullthrough is acceptable without an interconnect or splice point. However, if the distance is greater than 90m, to be standards compliant, you must put in either an interconnect or splice point.

In your cost model, environmental controls are a significant expense. Are they really necessary?^top

It depends on the nature of the building. If the temperature in the TR gets too hot or too cold it can cause premature failure of the electronics. For example, when a building needs heat, often times the TR needs cooling. Environmental control is particularly important during weekends and vacation time, even though temperatures in the main building may not need to be so highly regulated.

Is fiber more difficult to install than copper?^top

No. Fiber is just as easy, and sometimes easier, to install than copper. Remember, since fiber is accepted as the standard choice for communications backbones for many years, today's installers are comfortable with the technology. In fact, new generation high-speed copper networks -- such as Category 5e and Category 6 Unshielded Twisted Pair (UTP) cable -- require more stringent and time-consuming installation techniques than those of fiber. Compared to newer grades of copper cable, fewer regulations exist on the methods by which optical cable is pulled and terminated. In addition, there is no need to worry about the location of EMI/RFI sources during installation. Furthermore, optical fiber cables are stronger, lighter and smaller than comparable copper cable designs, and there are few routing restrictions, particularly in areas with other electrical power cables.

Is it easy to test fiber links?^top

Yes, in fact, it's easier than testing copper links. Since fiber cable facilities are not affected by near-end cross talk (NEXT) and their operating performance is not affected by frequency, technicians can test runs by simply measuring the attenuation of the optical fiber link. In comparison, to verify the performance of Category 5e links, tests must be conducted for attenuation, cable length and crosstalk. Technicians must also perform attenuation and NEXT tests across the entire frequency range of 1-100 Megahertz or higher because the performance of copper-based systems changes at different frequencies.

Are there any applications that require fiber?^top

The 10 Gigabit Ethernet standard currently is an all-fiber standard. However, while copper can be used for other high-speed protocols, often the link distances supported by standards are very short. Fiber cable, on the other hand, can often support links of up to 300 meters, even at high data rates. The increasing need for security is also driving users to deploy fiber. In fact, it is required for many government applications.

I have an existing copper infrastructure, what's the most cost-effective way to upgrade to fiber?^top

For companies that want to leverage their legacy electronics, need to upgrade only a portion of their network, or do not have the resources to upgrade their entire network at once, fiber can be installed incrementally. For these users, media conversion technology offers them a controlled migration strategy. Media converters do just what their name implies -- the devices convert the signal from one type of media to another, allowing seamless links between different media and supporting incremental upgrades to fiber. Media converters also allow users to continue to use their existing electronics, leveraging their existing investment.

What's the difference between 62.5 micron and 50 micron fibers?^top

Physically the two fiber types differ in the diameter of their cores, the light-carrying region of the fiber. This is signified by the numeric nomenclature. In 62.5/125 fiber, for example, the core has a diameter of 62.5 microns and the cladding diameter is 125 microns. In terms of performance, the difference lies in the fibers' bandwidth, or information-carrying capacity. Bandwidth is actually specified as a bandwidth-distance product with units of MHzkm. The bandwidth needed to support an application depends on the data rate. As the data rate goes up [MHz], the distance that rate can be transmitted [km], goes down. Thus, a higher fiber bandwidth enables you to transmit at higher data rates or for longer distances. 50 mm multimode fiber offers nearly three times more bandwidth (500 MHzkm) than FDDI-grade 62.5 mm fiber (160 MHzkm) at 850 nm. Network planners often choose 50 micron fiber when they know the network will need to carry high bandwidth applications over longer link distances, or when they anticipate running higher speed protocols in the future.

Why do I need to install optical fiber?^top

Network managers choose to install optical fiber for several reasons, depending on their application. A few of the major reasons are listed below. Longer link lengths: Because of it's high bandwidth and low attenuation, fiber cable can support link lengths of up to 300 meters, compared to 90 meters for UTP copper cabling. Many network designers use this attribute to centralize their network electronics into a single telecommunications room. By doing this, they can significantly reduce network costs and simplify network maintenance. Network Longevity: Over the last decade, when there have been three grades of UTP copper introduced, the same two multimode fiber types (62.5/125 micron and 50/125 micron) have proved their longevity by continuing to support increasing bandwidth needs and higher-speed protocols -- without the need (and the resulting expense and downtime) to pull new cable. Today, multimode fiber offers the same promise: the ability to support your network needs well into the future. While these traditional fibers continue to support high speed applications, a new laser-optimized multimode fiber is now available for companies that anticipate the need to support 10 Gigabit Ethernet in their backbones. EMI/RFI Immunity: In some installations -- particularly industrial applications and some schools and hospitals -- electromagnetic interference (EMI) or radio frequency interference (RFI) from fluorescent lighting or industrial equipment can cause network problems. Because fiber is non-dielectric, it is immune to these problems. In addition, unlike copper facilities, all-dielectric fiber cabling systems do not conduct lightning strikes or electrical currents that can damage sensitive electronic transmission equipment.

I already have TRs in my building, is Centralized Cabling appropriate for an upgrade?^top

Centralized cabling is more frequently used for new builds, because then network designers can plan spaces more efficiently. However, there are existing installations that have been able to successfully "reclaim" space that had been allocated to TRs. Some additional benefits of going to a centralized fiber architecture is that your port utilization improves and the number of points of administration decreases. By moving all of your equipment into one central location it is also easier to secure and troubleshoot the network. This configuration also enables greater energy efficiency because you eliminate the need for cooling in the TR and for the inclusion of a UPS, or the availability of an uninterruptible power supply distributed from a central source.

Aren't fiber solutions more expensive than UTP copper solutions?^top

Not necessarily. Recent cost modeling completed by the Fiber Optics LAN Section shows that when centralized cabling or Fiber to the Telecommunications Enclosure (FTTE) designs are used, many fiber systems are actually less expensive than networks using fiber in the backbone and UTP copper in the horizontal.

Do media converters add a point of failure to the network? Why would I want to use them?^top

Media converters have extremely high reliability statistics. In fact, although some companies have viewed them as a temporary, migration solution, they have been so pleased with their performance that they made them permanent. Media converters are ideal for companies that have an existing copper infrastructure that want to upgrade the parts of their network that need increased bandwidth or higher speed transmission rates now, while at the same time leveraging existing electronics.

What are SFF connectors, and why should I consider them?^top

Small Form Factor (SFF) connectors were introduced several years ago by a number of different manufacturers. They are smaller than traditional fiber connectors, with a footprint similar in size to copper-based connectors. As a result, they hel increase port density, reduce the cost of hubs and switches, lower patch-panel and enclosure costs, and reduce jumper costs. They are easy to install, making fiber even faster to install.

Since fiber is made of glass, will it survive harsh conditions?^top

Optical fiber is not your typical kind of glass. Made of ultra-pure silica, it is an extremely strong material that has the ability to handle exposure to temperature and pressure extremes. In fact, tensile strength (resistance to pulling) of optical fiber exceeds 600,000 pounds per square inch -- making it stronger than copper or steel strands of the same diameter and easily surpassing the strength requirements of today's communications applications. When cabled, glass fiber is protected and further strengthened by aramid or fiberglass yarns, a fiberglass rod, and/or an outer jacket constructed of non-conductive materials.