The ratio of (a) the total time a functional unit is capable of being used during a given interval to (b) the length of the interval. Note 1: An example of availability is 100/168 if the unit is capable of being used for 100 hours in a week. Note 2: Typical availability objectives are specified in decimal fractions, such as 0.9998.

The Internet backbone refers to the main "trunk" connections of the Internet. It is made up of a large collection of interconnected commercial, government, academic and other high-capacity data routes and core routers that carry data across the countries, continents and oceans of the world.

A redundant safety system that is used when the primary device malfunctions.

In computer networks, bandwidth is often used as a synonym for data transfer rate - the amount of data that can be carried from one point to another in a given time period (usually a second). This kind of bandwidth is usually expressed in bits (of data) per second (bps). Occasionally, it's expressed as bytes per second (Bps). A modem that works at 57,600 bps has twice the bandwidth of a modem that works at 28,800 bps. In general, a link with a high bandwidth is one that may be able to carry enough information to sustain the succession of images in a video presentation. It should be remembered that a real communications path usually consists of a succession of links, each with its own bandwidth. If one of these is much slower than the rest, it is said to be a bandwidth bottleneck.

The placement of in-service, customer telecommunications equipment at a carrier's central office (CO), point of presence (POP), or other network location.

In installing hardware and software, configuration is sometimes the methodical process of defining options that are provided.

An optical fiber cable is a cable containing one or more optical fibers. The optical fiber elements are typically individually coated with plastic layers and contained in a protective tube suitable for the environment where the cable will be deployed.

Network Load Balancing (commonly referred to as dual-WAN routing or multi homing) is the ability to balance traffic across two WAN links without using complex routing protocols like BGP (Border Gateway Protocol)

Multi Protocol Label Switching (MPLS) is a data-carrying mechanism that belongs to the family of packet-switched networks. MPLS operates at an OSI Model layer that is generally considered to lie between traditional definitions of Layer 2 (Data Link Layer) and Layer 3 (Network Layer), and thus is often referred to as a "Layer 2.5" protocol. It was designed to provide a unified data-carrying service for both circuit-based clients and packet-switching clients which provide a datagram service model. It can be used to carry many different kinds of traffic, including IP packets, as well as native ATM, SONET, and Ethernet frames.

Multihoming is a technique to increase the reliability of the Internet connection for an IP network.With the use of a routing protocol, in most cases BGP, the end-site announces this address space to its upstream links. When one of the links fails, the protocol notices this on both sides and traffic is not sent over the failing link any more. Usually this method is used to multihome a site and not for single hosts.

Multicast is the delivery of information to a group of destinations simultaneously using the most efficient strategy to deliver the messages over each link of the network only once, creating copies only when the links to the destinations split.

Redundant describes computer or network system components such as switches, and telecommunication links that are installed to back up primary resources in case they fail.

The information moved over a communication channel.

Technical term for data transmission in the direction from the subscriber to the Internet provider.

Uninterruptible power supply (UPS): A device that is inserted between a primary power source, such as a commercial utility, and the primary power input of equipment to be protected, e.g., a computer system, for the purpose of eliminating the effects of transient anomalies or temporary outages. Note 1: An UPS consists of an inverter, usually electronic, that is powered by a battery that is kept trickle-charged by rectified ac from the incoming power line fed by the utility. In the event of an interruption, the battery takes over without the loss of even a fraction of a cycle in the ac output of the UPS. The battery also provides protection against transients. The duration of the longest outage for which protection is ensured depends on the battery capacity, and to a certain degree, on the rate at which the battery is drained. Note 2: An UPS should not be confused with a standby generator, which may not provide protection from a momentary power interruption, or which may result in a momentary power interruption when it is switched into service, whether manually or automatically