Broadband Technologies

Broadband Dictionary

Analog: Continuous and variable electrical waves that represent an infinite number of values. Opposite of analog is digital.

ATM: Asynchronous Transfer Mode. A method for the dynamic allocation of bandwidth using a fixed size packet (called a cell). ATM is also known as "fast packet".

Backbone: The primary connectivity mechanism of a hierarchical distributed system. All systems which have connectivity to an intermediate system on the backbone are assured of connectivity to each other. This does not prevent systems from setting up private arrangements with each other to bypass the backbone for reasons of cost, performance, or security.

Bandwidth: Bandwidth refers to how fast data flows through the path that it travels to your computer; it's usually measured in kilobits, megabits or gigabits per second.

Broadband: Broadband comes from the words "broad bandwidth" and is used to describe a high-capacity, two-way link between an end user and access network suppliers capable of supporting full-motion, interactive video applications.

Cable modem: Refers to the type of broadband connection that brings information to homes and businesses over ordinary television cable lines.

Downstream speed: Refers to the speed at which data flows from the information server to your computer.

DSL: Stands for digital subscriber line; it refers to the type of broadband connection that brings information to homes and businesses over ordinary copper telephone lines.

Ethernet: A computer network cabling system designed by Xerox in the late 1970s. Originally transmission rates were 3 Megabits per second (Mb/s) over thick coaxial cable. Media today include fiber, twisted-pair (copper), and several coaxial cable types. Rates are upto 10 Gigabits
per second or 10,000 Mb/s.

Fast Ethernet: A version of Ethernet that operates at 100 Mbps. Fast Ethernet is in the form of an Ethernet hub with an internal bus that runs at 100 Mbps.

Gigabit: One thousand million bits. The number of bits that be transmitted in one second.

Gigabit Ethernet: A variant of Ethernet that operates over multimode fiber optic cable, single mode fiber optic cable, or unshielded twisted pair, at 1000 Mbps.

Hub: A common connection point for devices in a network that takes an incoming signal and repeats it on all other ports. Hubs operate at the physical layer.

Kbps: Stands for Kilobits per second, or thousands of bits per second. For example, most analog modems transmit at 56 Kbps or 28.8 Kbps.

LAN: Local Area Network. A data network intended to serve an area of only a few square kilometres or less. Because the network is known to cover only a small area, optimizations can be made in the network signal protocols that permit data rates up to 1000Mb/s.

MAN: Metropolitan Area Network. A data network designed for a town or city. In terms of geographic breadth, MANs are larger than local-area networks (LANs), but smaller than wide-area networks (WANs). MANs are usually characterized by very high-speed connections using fiber optical cable or other digital media.

Mbps: Stands for Megabits per second, or millions of bits per second. This is a measurement of how much data can be transmitted through a connection. For example, 6.0 Mbps is 200 times faster than a 28.8 Kbps analog modem.

Network: A computer network is a data communications system which interconnects computer systems at various different sites. A network may be composed of any combination of LANs, or WANs.

Packet: The unit of data sent across a network. "Packet" a generic term used to describe unit of data at all levels of the protocol stack, but it is most correctly used to describe application data units.

Protocol: A formal description of message formats and the rules two computers must follow to exchange those messages. Protocols can describe low-level details of machine-to-machine interfaces (e.g., the order in which bits and bytes are sent across a wire) or high-level exchanges between allocation programs (e.g., the way in which two programs transfer a file across the
Internet).

Router: A system responsible for making decisions about which of several paths network (or Internet) traffic will follow. To do this it uses a routing protocol to gain information about the network, and algorithms to choose the best route based on several criteria known as "routing
metrics.

Satellite: Refers to the type of broadband connection where information is sent from and arrives at a computer through satellite dishes.

Switching hub: A switching hub remembers what devices are connected to each port and only sends data to the required port. Each port has the full bandwidth and is not required to share it unlike ordinary hubs.

Switch: Controls the traffic flow of frames across a network by providing a dedicated connection. Switches operate at the data link layer.

Twisted pair: A wiring scheme that uses standard pairs of copper wires. Twisted pair might be used for normal telephone connections, serial data links, or twisted pair Ethernet.

Upstream speed: Refers to the speed at which data flows from your computer to the information server.

Wireless: Refers to the type of broadband connection where information is sent from and arrives at a computer through transmission towers.

Updated: 2005-01-28

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