BROADBAND & WIRELESS GLOSSARY

» ADSL -- (Asymmetric Digital Subscriber Line)

A DSL line where the upload speed is different from the download speed. Usually the download speed is much greater.

» Backbone Network (BN)

A large network to which many networks within an organization are connected. It usually is a network that interconnects most of all networks on a single site.

» Bandwidth

The difference between the highest and lowest frequencies in a band. For example, a voice-grade cirucuit has a 4000 hertz bandwidth. In common sage, bandwidth refers to circuit capacity; when people say they need more bandwidth, they need a higher transmission speed

» Bit

1. An abbreviation of the term bianary digit.
2. A single pulse in a group of pulses.
3. A nuit of information capacity

» Channel

A path for transmission of electromagnetic signas. Or A data communication path. Each T-1 has 24 channels.

» Circuit

The path over which the voice, data, or image transmission travels. Circuit can be twisted-pair cables, coaxial cables, fiber optic cables, microwave transmissions, and so forth.

» DSL - SDSL - ADSL - VDSL

DSL - Digital Subscriber line. "Various technology protocols for high-speed data, voice and video transmission over ordinary twisted-pair copper POTS (Plain Old Telephone Service) telephone wires."
SDSL - symmetric DSL provides the same data transmission rate to and from the telephone network, often 1 Mbps in both direction.
ADSL - Asymmetric DSL provides lower upstream data rates , usually only 64 Kbps, combined with faster downsteam rate (i.e from the network), usually 1.544 Mbps.
VDSL - Very high-speed DSL provides much faster asymmertic rates, usually over very short distances (often 1.6 Mbps upstream and 51 Mbps downstream)

» Fractional T1

A portion of a T-1 circuit. A full T1 allows transmission at 1.544,000 bits per second (1.544 Mbps). A fractional T1 circuit allows transmission at lower speed of 384 Kbps, 512 Kbps, 768 Kbps.

» Frame Relay (Frame-relay)

Frame Relay is a type of packet switching technology that transmits data faster than the X.25 standard. The different that is unlike X.25 networks, frame relay does not perform error correction at each computer in the network. Instead, it simply discards any messages with errors. It is up to the application software at the source and destination to perform error correction and to control the lost messages.

In the context of computer networking, frame relay (also found written as "Frame-relay") consists of an efficient data transmission technique used to send digital information quickly and cheaply in a relay of frames to one or many destinations from one or many end-points. Network providers commonly implement frame relay for voice and data as an encapsulation technique, used between local area networks (LANs) over a wide area network (WAN). Each end-user gets a private line (or leased line) to a frame-relay node. The frame-relay network handles the transmission over a frequently-changing path transparent to all end-users.

» Internet Access Providers

Access providers offer connections to the internet via a modem. Some access providers charge a flat monthly fee for unlimited access (much like the telephone company), while others charge per hour of use (much like long distance comapny).

» ISP

Internet Service Provider (ISP). A company providing access to the internet.

» Leased Line

A leased communication circuit that goes from your site to some other location. It is a clear, unbroken communicatin path that is yours to use 24x7. Also called Private Line or Dedicated Line.

» Line

A circuit, channel, or link. It carries the data communication signals. An early telephone technology term that may imply a physical connection, such as with a copper wire.

» Link

An unbroken circuit path between two points. Sometimes called a line, channel, or circuit.

» Local Loop

The part of a communication circuit between the subscriber's equipment and the equipment in the local central office.

» MAN

A network that usually covers a city-wide area. Because MANs use local area network and fiber optic technologies, transmission speeds can very from 2 million to 100 million bits per second.

» Point-to-point

Denoting a circuit, channel, or line that has only two terminals.

» POP

Point of presence - The point to which the local phone company terminates subscribers' circuit for long distance leased lines. The closer your company location is from the POP of the local phone company the lower local loop charges for the T1, T3 or DS3, OC3, other circuits.

» WAN

A network spanning a large geographical area. its nodes can span city , state, or national boundaries. They typically use circuits provided by common carriers. Contrast with backbond network, LAN, MAN.