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Glossary of Terms
The following list of data and telecommunication terms are defined in the glossary. Click on a term to go to the definition. If you encounter a term on our web site or product literature that you do not understand, please contact us at info@hvdata.net and tell us about it. We will attempt to answer your questions in a timely manner.
ADSL: Asymmetric Digital Subscriber Line is a technology, which facilitates the transmission of digital data over conventional telephone lines designed to carry analogue. ADSL uses existing telephone lines and splits the frequencies between data and voice.
ATM: Asynchronous Transfer Mode. ATM is a protocol that packs digital information into 53-byte cells (5-byte header and 48-byte payload) that are switched throughout a network over virtual circuits. ATM's ability to accommodate multiple types of media (voice, video, data) makes it a likely player for full service networks based on ADSL and VDSL
Backbone: That part of a network that is used as the main path for carrying traffic between network endpoints.
Bandwidth: Size or the capacity of a given transmission channel. In digital transmission, bandwidth is normally described in bits per second.
Bandwidth-on-Demand: A network service whereby a customer has on-demand access to any amount of bandwidth required at any given point in time.
Broadband: A type of transmission that has transmission capability greater than a standard voice-grade line. A coaxial cable, used in cable television, is a broadband channel, as are digital subscriber line (DSL) technology. Fiber optic technology is a broadband medium, which offers even greater capacity than coaxial or copper cable technology.
Burst Mode: A high-speed transmission mode in a communications or computer channel. Under certain conditions, the system sends a burst of data at higher speed for a limited amount of time.
Circuit Switched Network: A network that establishes a physical circuit temporarily on demand (as when a telephone or other connected device goes off hook) and keeps that circuit reserved for the user until it receives a disconnect signal.
CLEC: Competitive Local Exchange Carrier. Created by the Telecommunications Act of 1996 to formally open the local communication business to competition.
Coaxial Cable: An enclosed wire used for broadband cable communications systems.
DSL: Digital Subscriber Line (DSL). Digital telephone lines that can carry both voice and data signals, 10 to 30 times faster than current standard modems. DSL allows telephone and Internet connections to run simultaneously over one line.
DS-0: Individual 56Kbps Point-to-point digital channel.
DS-1: Digital channel operating at 1.544Mbps. [Back to Top]
DS-3: Digital channel operating at 44.736Mbps.
Ethernet: A network protocol that transfers data at 10/100Mbps/sec across a linear bus topology, over a single cable.
Frame Relay: A form of packet switching, that uses smaller packets and less error checking than traditional forms of packet switching (such as X.25). Now a new international standard for efficiently handling high-speed, bursty data over wide area networks.
Headend: The principle location for network electronics, where local access loops and connections are aggregated for the purpose of routing consolidated traffic through the main ring and to the national backbone network.
IT: Information Technology. A term that has come into broad use over the last decade, basically as a replacement for what used to be most often called data processing and management information systems. Refers to most anything in the computer, networking and telecom fields.
IP: Internet Protocol. The TCP (Transmission Control Protocol)/IP is a networking protocol that provides communication across interconnected networks, between computers with diverse hardware architectures and various operating systems. TCP and IP are only two protocols in the family of Internet protocols. Over time, however, "TCP/IP" has been used in industry to denote the family of common Internet protocols.
ISP: Internet Service Provider. An ISP is a telecommunications company that provides subscriber access to the Internet. These are the organizations from which you purchase Internet service.
LAN: Local Area Network. A LAN is a data communications network covering a small area, usually within the confines of a building or floors within a building. Common LAN protocols are Ethernet and Token Ring.
Intranet: A local network, (e.g. an office network) where there are internal web servers accessible to computers in the office, but not accessible from outside the company. Many Intranets are protected from exterior access by various security devices, like firewalls.
Node: A point on a network for the ingress and egress of communication traffic. The node is where the customer connects to the communications network provider.
OC-1: Optical Carrier 51.84Mbps (28DS1s or 1DS3).
OC-3: Optical Carrier 155.52 Mbps.
OC-12: SONET transmission rate of 622.08 Mbps.
OC-48: SONET transmission rate of 2488.32Mbps.
Packet Switched Network: A network that does not establish a dedicated path through the network for the duration of a session, rather it transmit data in units called packets in a connectionless manner. Data streams are broken into packets at the front end of a transmission, sent over the best available network connection, and then reassembled in their original order at the destination endpoint.
Path Diversity: Routing network cabling to ensure that any circuit in a protected ring configuration such as SONET will be safe from being disabled by a single circuit cut or equipment failure.
Portal: Entry point or window into the Internet.
POP: Point of Presence. A location where a local network provider connects to interexchange carriers for the purpose of handing communications traffic to each other.
Private Network: A network that is closed to outside access and is only available to the entities within a private group such a business.
Redundancy: A duplication of elements within a network for purposes of making the network more fail-safe from individual network component failures. Route Diversity: See path diversity.
Router: A device that connects multiple computer networks. Packet information is read and then forwarded to the appropriate end station. Routers can find the best route between any two networks, even if there are several different networks in between. Routers provide network management capabilities such as load balancing, partitioning of the network, use statistics, communication priority, and trouble shooting tools that allow network managers to detect and correct problems even in a complex network of networks.
Sheath Diversity: A method of network diversity that relies on conductors/fibers from within two distinctly different cable sheaths.
SONET: (Synchronous Optical Network) A fiber-optic transmission system for high-speed digital traffic employed by telephone companies and common carriers. SONET speeds range from 51 megabits to multiple gigabits per second. SONET is an intelligent system that provides advanced network management and a standard optical interface. It uses a self-healing ring architecture that is able to reroute traffic if a line goes down. SONET backbones are widely used to aggregate lower-speed T-1and T-3 lines.
Streaming: The ability to play back audio and video content as it is sent from one computer to another. Software programs that enable streaming audio and video can be used on private networks or on the Internet. They can deal with one-way transmission of audio, video, or both. Video and audio conferencing, by contrast, provide for real-time two-way transmission.
Subtended Ring: A SONET based fiber optic ring that shares a node with the network's primary fiber ring, in order to pass traffic to/from the nodes of the primary ring. Typically, a subtended ring is utilized to connect a distant clustered group (or community) to the main fiber network.
TCP: Transmission Control Protocol. The TCP/IP (Internet Protocol) is a networking protocol that provides communication across interconnected networks, between computers with diverse hardware architectures and various operating systems. TCP and IP are only two protocols in the family of Internet protocols. Over time, however, "TCP/IP" has been used in industry to denote the family of common Internet protocols.
Telecommunications Act of 1996: An act passed by the US Congress that reformed the telecommunications industry. The Act called for the incumbent telephone companies (ILECS) to open their markets to competition. Specifically creating competition in the local market place by CLECs, such as Hudson Valley DataNet, LLC.
TI: A digital transmission link with a capacity of 1.544 Mb/s. Typically channeled into 24 DSOS, each capable of carrying a single voice conversation or data stream. Uses two pairs of twisted pair wires.
VDSL: Video Digital Subscriber Line. VDSL is a technology, which facilitates the transmission of digital video over conventional telephone lines designed to carry analogue. VDSL uses existing telephone lines and splits the frequencies between video and voice. Videoconferencing: The use of digital video transmission systems to communicate between sites using video and voice. Digital video transmission systems typically consist of camera, codec (coder-decoder), network access equipment, network, and audio system.
Virtual Private Network: A private network that is configured within a public network. WAN: Wide Area Network. A WAN is a data network usually extending a LAN (Local Area Network) outside the building, possibly in remote cities. A WAN typically uses common-carrier lines. A LAN does not. WANs generally run over leased telephone lines, from an analog telephone line to a T1 (1.544Mbps) line. The connection between a LAN and a WAN is made via a router.
Wireless: Transmission via the airwaves. Various techniques are used to provide wireless communications, including cellular, microwave and satellite.
10/100 BaseT: Local area network protocols. 100 BaseT maintains backward compatibility with 10baseT networks running at 10Mbps.