Fiber vs. Copper

Network system designers for projects that range from industrial manufacturing installations to data centers must consider a wide range of variables and anticipated demands when specifying data infrastructure highways.

Current technology provides two primary choices for design mediums.

Traditional twisted-pair copper wire and cabling

Fiber optic systems using both conventional and blown-cable design.

Industrial data centers are growing in size and complexity, and current estimates indicate 90% of active equipment will be replaced within five years. An efficient modular infrastructure, therefore, is required to adapt to fast-moving business requirements, increasing port and cable densities, and rapid deployment needs.

Infrastructure decisions made at the design stage often have a big impact on future expansions. Initial copper cable material and costs typically are 40-50% less than fiber solutions. As a result, they often are the design of choice whenever budgetary considerations are paramount. Growing demand for fiber, however, has resulted in more favorable pricing for new fiber optic system backbone installations.

Upfront costs must be weighed against long-term considerations of performance, future deployment costs to support business changes, space limitations, and modular flexibility for expanding bandwidth capabilities.

he Roads are Different

Twisted-pair copper wires are used to transmit electrical currents and drive data primarily through the proven media of Category 6 (CAT6) cabling. Cost of copper cabling per the IEEE 10 Gig Ethernet standard are currently projected at 40% of 10 Gig fiber networks for linkages of less than 100 meters. For many small- to mid-sized industrial projects, this can be an attractive approach. The copper cable industry is also pursuing CAT8 twisted-pair products to double the capacity of CAT6.

Drawbacks compared to fiber include greater power demands for high-speed data transmission via electrons rather than optical photons. Electrons moving at high-speed must overcome greater resistance and require more power to process signals. In addition, more expensive and complex environmental and cooling systems are needed to manage the heat byproduct of a copper-based data center.

Fiber optic cable consists of fiber strand bundles of optically pure glass tubes. These can be fabricated in a variety of configurations and transmission specifications. Typical fiber optic cables are built and rated for indoor or outdoor applications. They can be obtained in fiber ribbon counts up to 3,456 in a cable diameter less than 1.5 inches. Other common sizes include 12-, 24-, 48-, and 72-count bundles. These usually are encased in a polyethylene foam jacket.

Digital information is carried through fiber via photons in a precise pathway. As such, data can move at higher speeds and over greater distances versus copper. This is due to minimal signal loss during data transmission. As a result, fiber optic solutions often have a strong upside for designs encompassing a large geographic area.

Fiber is lighter than copper and has a smaller installation footprint. Large projects for corporate data centers or industrial feeds are typically carried out in both supported (cable trays, aerial hooks, and so on) as well as direct-feed configurations. For direct feed, specialty tubing can be used for buried or impact-resistant applications.

It’s All About the Bandwidth

From a manufacturing viewpoint, technology-driven advances have transformed the world into a grand scale “information system,” which some believe will trigger a new industrial revolution.

Physical objects now have embedded sensors and actuators that can be linked through wired and wireless networks via Internet protocols. Bandwidth demands will likely continue to grow as business and industrial enterprises move toward decentralized controls for production and supply chain logistics.

The past decade has seen strides in wireless technology for industrial networks. The reason is clear: With wireless communications, no direct cabling is required. However, growing bandwidth constraints with wireless (particularly video over wireless) have generated increasing demands for high-speed data highways.

In bandwidth performance, optical fiber has demonstrated a convincing upside versus copper cable due to the extremely high frequency ranges the optical glass is able to carry. With copper wire, signal strength diminishes at higher frequencies. CAT6 twisted-pair copper can be optimized for data rates of 500MHz over a distance of 100 meters. In comparison, multi-mode optical fiber would have a bandwidth in excess of 1000 MHz over the same distance.

In terms of Ethernet infrastructure standards, copper is a compatible choice up to 1.0 Gigabit applications. Optical fiber, however, has demonstrated transfer rates of 10 gigabits/second (Gbps). Movement toward 40-100 Gbps is a next threshold standard. A copper solution for a 10-Gigabit Ethernet is not a commercial reality at this time, making these applications only suitable for fiber.

A Case for Blown Optical Fiber?

Blown fiber technology originated with British Telecom in 1982 and provided a method to upgrade capacity or to change fiber type without prohibitive infrastructure costs.

In a ground-up blown fiber installation, “highways” of tube cable are installed in buried, riser, or plenum rated tubing constructions. The tube cables can then be populated with single- or multi-mode fibers in various configurations up to 48 fiber optic tubes per bundle. Precise geometric patterns manufactured into the fiber bundle jackets provide aerodynamic properties to the bundles. They then can be “blown” into the pathways via a customized nitrogen-driven air motor system.

Manual installations that previously required large crews and disruptions to existing operations can now be accomplished with a single pair of skilled workers trained in blowing techniques. Installation lengths of 4,000-6,000 feet are typical, with end-end completion times averaging 6-8 man-hours.

Blown optical fiber can be cost-effective in next-generation backbone upgrades within a given facility or in expansions to new locations. It can be blown in at a rate of 200 feet/minute. It also may be blown out at the same rate for additional or upgraded capacity.

Cost and complexity of future expansions are minimized without the labor-intensive steps of laying new conduit and disrupting operational areas. For the visionary designer, the up-front costs of installing a high-speed blown fiber network can more than pay for themselves by lowering the cost of future upgrades.

Copper or Fiber Infrastructure?

Arriving at the “perfect” solution for a cabling infrastructure is a difficult task that requires careful analysis of a large number of variables. These can include bandwidth demands, immunity to electrical interference, density of the connectivity space, flexibility/speed of reconfiguration, cost of electronics, device interface considerations, and budgetary constraints.

Copper’s initial low investment cost often makes it a viable alternative for compact and single-building data center needs where data transfer rates of less than 2 Gbps will meet current and future needs. Copper can be considered for relatively short data transmission distances within a defined building footprint where environmental challenges, temperature fluctuations, and electromagnetic interference have a minimum impact on signal integrity.

The initial higher costs of fiber-optic solutions can be offset with its much greater bandwidth properties and virtually error-free transmissions over large distances. Optical data center solutions provide generally simple and easy installations up to 75% faster than pulled copper cables. Fiber can also deliver considerable performance, time, and cost savings both for initial and for future infrastructure needs.

Original website: http://insights.globalspec.com/arti...