Look up definitions to commonly-used industry terms, phrases, and abbreviations.
The portion of fiber optic attenuation resulting from conversion of optical power to heat.
The open space between rows of racks. Best-practice dictates racks should be arranged with consistent orientation of front and back to create ‘cold’ and ‘hot’ aisles.
Alternating Current (AC)
The designation given to power that is delivered in the form of a sinusoidal wave form. AC won out over DC as the preferred method of delivering and using power in the industrial age due to the ease of voltage transformation using static devices (transformers).
A unit of electrical current.
Signals that are continually changing, as opposed to being digitally encoded.
Extra protection for a cable, improves resistance to cutting and crushing – most commonly steel wire.
A decrease in transmission power in an optical fiber – low attenuation means low transmission loss.
A device that reduces signal power in a fiber optic link by inducing loss.
The total amount of space that is currently being marketed as available for lease in a given time period. It includes any space that is available, regardless of whether the space is vacant, occupied, available for sublease, or available at a future date.
In computing, bandwidth is the maximum rate of data transfer across a given path. Bandwidth may be characterized as network bandwidth, data bandwidth, or digital bandwidth.
Loss in fiber caused by stress on the fiber bent around a restrictive radius.
Adapter where a loose tube containing 2 optical fibers can be split into 2 single fiber cables (see loose tube).
A computer optimized to use minimal physical space and power without compromising functionality. A standard data center rack can hold 42 1RU servers vs. 128 blade servers.
Blanking panels make data center cooling systems run more efficiently by blocking the transfer of hot and cold air in empty rack space. Blanking panels provide low-cost protection against overheating along with noticeable savings on energy costs. Most models are easy to install and fit standard cabinet openings.
Material surrounding fiber to protect it from physical damage
Device for holding IT equipment, also called a rack.
One or more fibers enclosed in protective coverings and strength members.
Capital Expenditure, the cost of purchasing capital equipment.
A data center facility that permits clients to contract with any telecommunication provider they choose.
Category 6 Cable
Commonly referred to as Cat-6, is a cable standard for Gigabit Ethernet and other network protocols that is backward compatible with the Category 5/5e and Category 3 cable standards. Cat-6 features more stringent specifications for crosstalk and system noise. The cable standard provides performance of up to 250 MHz and is suitable for 10BASE-T / 100BASE-TX and 1000BASE-T / 1000BASE-TX (Gigabit Ethernet). It is expected to suit the 10GBASE-T (10Gigabit Ethernet) standard, although with limitations on length if unshielded Cat 6 cable is used. Category 6 Cable can be identified by the printing on the side of the cable sheath.
Ceiling to Deck Height
The space between a suspended or false ceiling and the structural surface above used as a distribution system that provides a pathway for cables serving the work area outlets from above.
Outermost region of optical fiber, acts as a barrier to prevent transmitted light leaking away from core.
A general term for anything that involves delivering hosted services over the Internet. These services are broadly divided into three categories: Infrastructure-as-a-Service (IaaS), Platform-as-a-Service (PaaS) and Software-as-a-Service (SaaS).
Cloud Storage API
An application program interface that connects a locally-based application to a cloud-based storage system, so that a user can send data to it and access and work with data stored in it. To the application, the cloud storage system is just another target device, like tape or disk-based storage.
An aisle where rack fronts face into the aisle. Chilled airflow is directed into this aisle so that it can then enter the fronts of the racks in a highly efficient manner.
The practice of locating critical technology assets, like computers, routers and data storage systems, in an off-site data center which specializes in managing the critical power and cooling infrastructure required to support computer operations.
A quality assurance-based process used to uncover deficiencies in design or installation via field verification. A formal review and integration of all project expectations during planning, design, construction, and occupancy phases by inspection and functional performance testing, oversight, and record documentation.
The center of the optical fiber through which light is transmitted.
An optical device that splits or combines light from more than one fiber.
A facility used to house computer systems and associated components, such as telecommunications and storage systems. It generally includes redundant or backup power supplies, redundant data communications connections, environmental controls (e.g., air conditioning, fire suppression), and security devices. Also includes colocation, a subset of data centers.
Data Center Shell
A building that has been pre-qualified for power and telecom access, with or without any other improvements, and amenable to data center development and use. May become a single-tenant property or colocation.
The provider operates and or rents server capacity to single customers. Server space is not shared by multiple customers. Typically the customer maintains full control over the server excluding maintenance.
Signals encoded into discrete bits.
Space that is being offered for lease directly from the landlord or owner of a building, as opposed to space being offered in a building by another tenant (or broker of a tenant) trying to sublet a space that has already been leased.
The temporal spreading of a pulse in an optical waveguide. May be caused by modal or chromatic effects.
A structure with terminations for connecting the cabling of a facility in such a manner that interconnection or cross-connections may be readily made.
A period of time, or a percentage of a time span, that a system is unavailable or offline. This is usually a result of the system failing to function because of an unplanned event or because of routine maintenance.
Radio waves and light are waves of energy associated with electric and magnetic fields and are forms of radiation occurring within the electromagnetic spectrum.
Emergency Power System
When regular power systems fail, a system that may include generators and other apparatus will provide backup power and lighting during an outage.
A precision tube which holds a fiber for alignment for interconnection or termination. A ferrule may be part of a connector or mechanical splice.
Number of times a signal occures in a given period, measured in Hertz or cycles per second.
An instrument that splices fibers by fusing or welding them, typically using an electrical arc.
Graded index profile describing how the refractive index of glass used in fiber optic alters gradually from core to cladding.
Green Data Center
Data centers being built with energy efficiency, environmental impact, and sustainability in mind.
Frequency equivalent to one cycle per second, named after the wireless pioneer Heinrich Hertz.
The service of running servers on behalf of another party, allowing those organizations to focus on managing their applications, instead of hardware and operating system administration. There are various levels of service and various kinds of hosting offered (e.g. dedicated, shared, virtual, etc.).
An aisle where rack backs face into the aisle. Heated exhaust air from the equipment in the racks enters this aisle and is then directed to the CRAC return vents.
Hot Aisle/Cold Aisle
An organized layout in which parallel aisles of equipment enclosures are arranged with rack fronts always facing rack fronts and rack rears always facing rack rears. This ensures separation between cooling air in the “cold” aisle entering the front of the racks and warm exhaust air leaving the back of the racks in the “hot” aisle. Separation of cooling air and exhaust air results in higher cooling system efficiencies and the ability to cool higher power densities in the computing environment.
Combining public and private clouds together, allowing for workloads to be processed on public cloud infrastructure, while others are run in private clouds.
An in-row cooling unit is designed to increase cooling efficiency by maximizing the dynamics of airflow inside a computer room. A unit is positioned between a server cabinet to provide cooling to the cold aisle and also handles return air from the hot aisle.
Form of light invisible to the human eye which travels down fiber.
Also known as cloud infrastructure services. Delivers computer infrastructure, typically a platform virtualization environment, as a service. Rather than purchasing servers, software, data center space, or network equipment, clients instead buy those resources as a fully outsourced service.
The loss caused by the insertion of a component such as a splice or connector in an optical fiber.
Internet Service Provider (ISP)
A company that provides access to the Internet.
A device that converts the battery DC output to AC.
Internet Protocol, a communications technology using the Internet for communications.
The protective outer coating of the cable.
A short single fiber cable with connectors on both ends used for interconnecting other cables or testing.
Pure light single wavelengths concentrated into a straight beam and used to transmit infrared along fiber – used for high data rate performance.
Light Emitting Diode. Transmits the infrared signal down the fiber.
Lights Out Server Room
A lights out server room functions as a center to house various servers. “Lights out” refers to the fact that lights are kept off within the room. Additionally, the room is kept locked and is devoid of IT personnel. Control of the servers is handled externally, either from another room in the complex or from a remote location. A lights out server room is considered to provide a high level of security.
A combination of transmitter, receiver, and the fiber optic cable connecting them capable of transmitting data. May be analog or digital.
Type of cable, more than one fiber in one cable tube.
A managed services provider manages and assumes responsibility for assets or objects on behalf of a customer.
The path taken by infrared light along fiber.
Moisture barrier built into cable to keep water out.
Buildings that house more than one tenant at a given time. Usually, multi-tenant buildings were designed and built to accommodate many different floor plans and designs for different tenant needs.
Optical fiber that carries more than one light signal.
A measure of redundancy where additional “spare” components are available in the event of a failure in one of the main critical components. N is the “Needed” components and +1 represents the spare component that is on hand for emergency use. N+1 safeguards against lost productivity if one component fails.
A redundancy model that ensures that every component has a backup so that the data center has no single point of failure.
A system of cables, hardware, and equipment used for communications.
A physical network connection bridging a telecommunications vendor with a customer’s computer environment inside a data center.
Operating Expense, the ongoing expenses related to operating the data center.
Boosts optical signal level without converting into electrical signal in the middle.
An optical waveguide comprised of a light carrying core and cladding which traps light in the core.
Optical Return Loss
Light reflected from the cleaved or polished end of a fiber caused by the difference of refractive indices of air and glass – typically 4% of the incident light. Expressed in dB relative to incident power.
A device that routes an optical signal from one or more input ports to one or more output ports.
Receiving end of fiber that converts light to electrical power.
A short length of fiber attached to a fiber optic component such as a laser or coupler.
A way to rent hardware, operating systems, storage, and network capacity over the Internet. The service delivery model allows the customer to rent virtualized servers and associated services for running existing applications or developing and testing new ones.
Plenum refers to the area where air circulates in systems running heating and air conditioning units. This space is commonly found between two ceilings or between a raised floor and the actual floor, and it often serves as a place where computer and telephone network cables are run.
Plastic coating applied to outer cladding of fiber as protection against contamination or damage.
Cloud infrastructure that is available to the general public and is owned by a large provider of cloud services.
Quad (4-Channel) Small Form-Factor Pluggable (QSFP)
A small form-factor pluggable is a compact, hot-pluggable network interface module used for both telecommunication and data communications applications.
Device for holding IT equipment (also called a cabinet).
A device containing a photodiode and signal conditioning circuitry that converts light to an electrical signal in fiber optic links.
The duplication of critical infrastructure support systems with the intention of backing up the primary systems and protecting against system down-time due to failure.
Refractive Index Profile
Optical density of an optical fiber alters across its diameter (bends signal like water).
Devices at regular intervals to detect weak signals and retransmit (sometimes called repeaters).
Reliability is classically defined as the probability that some item will perform satisfactorily for a specified period of time under a stated set of conditions.
The ability for the required infrastructure to be enlarged or handle increased capacity input without efficiency or reliability being compromised.
The change of direction of light after striking small particles that causes loss in optical fibers.
Outer finish of cable (usually PVC or Polythylene).
A cabinet designed to hold a network device that combines hardware and software to provide and manage shared services and resources on the network.
A location specifically designed to house a high concentration of information technology equipment.
In a control system, this is the value against which the variable that is being controlled is compared. Temperature and humidity set points are common in the cooling system for a data center.
Pure glass used to make fiber optic cable.
An optical fiber so construced that light travelling along the core can follow only one path (also called monomode).
Buildings that are occupied, or intended to be occupied, by a single tenant.
The connection between two fibers, typically intended to be permanent.
Step index profile; how refractive index glass used in optical fiber graduates, from highest to lowest density, the shift from one level of density to another causes the light to bounce as it travels.
Part of an optical fiber cable which removes any strain on the fibers.
Preparation of the end of a fiber to allow connection to another fiber or an active device, sometimes also called “connectorization”.
A type of cable in which the optical fibers are encapsulated in plastic material.
Interleaving digital signals to increase data rates.
Total Internal Reflection
Confinement of light into the core of a fiber by the reflection off the core-cladding boundary.
A device which includes an LED or laser source and signal conditioning electronics that is used to inject a signal into fiber.
Virtualization is a framework or methodology of dividing the resources of a computer into multiple execution environments, by applying one or more concepts or technologies such as hardware and software partitioning, time-sharing, partial or complete machine simulation, emulation, quality of service, and many others.
Visual Fault Locator/Indicator (VFL/VFI)
A device that couples visible light into the fiber to allow visual tracing and testing of continuity. Some are bright enough to allow finding breaks in fiber through the cable jacket.
A measurement of the length of any electromagnetic wave. The shorter the wavelength, the higher the frequency.
Using more than one wavelength of light in the same fiber to allow greater rates of information transmission.