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10 Glossary of terms
analog - A continuously varying signal or wave. Telephone transmission and/or switching that is not digital.
ADSL - Asymmetric Digital Subscriber Line - A group of DSL technologies that are asymmetric, thereby reserving more downstream bandwidth (coming to the user from the Internet) than upstream bandwidth (going from the user to the Internet). This type of
DSL is advantageous for residential users that do not need the same bandwidth speed in both directions. Also see DSL
ATM - ATM Asynchronous Transfer Mode - A method of data transportation whereby fixed-length cells are sent over a switched network. Because of its uniform handling of services, one network can meet the needs of many broadband users, for the receipt of voice, video, and data.
bandwidth - A measure of the width or capacity of a communications channel. Greater bandwidth allows communication of more information in a given period of time.
Bandwidth is generally described either in terms of analog signals in units of Hertz (Hz), which describes the maximum number of cycles per second, or in terms of digital signals in units of bits per second (bps).
bit - The basic unit in data communications, represented as either a one or a zero.
When discussing digital data, a small "b" refers to bits, and a capital "B" refers to bytes.
bit rate - the number of bits of data transmitted over a phone line per second broadband - Broadband is the largest size bandwidth category, meaning that there are the most channels of data moving over a single communication medium, thus information such as data, voice, and video can be received and sent most quickly.
dedicated connection - A communication link that operates constantly.
dial-up connection - A data communication link that is established when the communication equipment (e.g. a modem) dials a phone number and negotiates a connection with the equipment on the other end of the link.
DSL - Digital Subscriber Line - A generic name for a family of digital lines being provided by CLECs and local phone companies to provide Internet access to their local subscribers.
DSLAM - Digital Subscriber Line Access Multiplexer - A device found in telephone company central offices that takes a number of DSL subscriber lines and concentrates them onto a single ATM line.
DMT - Discrete Multi-Tone Modulation - A method of transmitting data on copper phone wires that divides the available frequency range into 256 sub-channels or tones, and which is used for some types of DSL.
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IP - Internet Protocol - The standard signaling method used for all communication over the Internet.
ISP - Internet Service Provider - An organization offering and providing Internet access to the public using computer servers connected directly to the Internet.
IP Address - A numeric identifier for your computer. Just as the post office delivers mail to your home address, servers know to deliver data to your computer based on your IP address. IP addresses can be dynamic, meaning that your computer "borrows" the IP address for the necessary timeframe, or they can be fixed, meaning that the number solely belongs to your computer.
MAC Address - Media Access Control address - a hardware address that has been embedded into the network interface card (NIC) by its vendor to uniquely identify each node, or point of connection, of a network.
Megabit - One million bits
Megabyte - 1,000,000 bytes, or 1,000 kilobytes. See byte .
modem (MOdulator-DEModulator) - A device that converts digital data into analog signals and vice-versa for transmission over a telephone or cable line.
NAT - Network Address Translation - Network Address Translation (NAT) enables a local area network (LAN) to use one set of IP addresses for internal traffic and a second set of IP addresses for external traffic. This feature is used by the HomePortal so an end user can have an internal computer network in their home, with all its computers using internal IP addresses, using only one routable IP address, which accesses the outside (Internet).
POTS - Plain Old Telephone Service - An acronym identifying the traditional function of a telephone network to allow voice communication between two people across a distance. In most contexts, POTS is synonymous with the public switched telephone network (PSTN).
PPP - Point-to-Point Protocol - Point-to-Point Protocol is a protocol which allows a computer to access the Internet using a dial-up phone line and a high-speed modem.
This can be accomplished over Ethernet (PPPoE), or over Asynchronous Transfer
Mode (ATM; PPPoA).
POTS splitter - A device that uses filters to separate voice from data signals when they are to be carried on the same phone line, required for several types of DSL service.
PPPoA - Point to Point Protocol over ATM. See Point to Point Protocol
PPPoE - Point to Point Protocol over Ethernet. See Point to Point Protocol
Request for Comment (RFC) 1483 - RFC1483 was developed to allow the successful transmission of multiple protocols over ATM networks. This RFC is broken down into two methods of implementation; VC based multiplexing and LLC encapsulation. The breakdown on both are mentioned below.
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