Glossary of Cable/Internet Terms

Best-Effort
A data delivery protocol that has no allowances for identifying or recovering lost or corrupted data packets.

Cable Modem Termination System (CMTS)
A major DOCSIS network element located in the headend or distribution hub, which manages the configuration of cable modems and modem data transmission and reception, as well as the interface to external networks such as the Internet and public switched telephone network (PSTN).

Channel Bonding
A logical process that distributes data packets across multiple independent RF channels during transport, then combines the data packets into one higher speed data stream at reception.

Data Over Cable Service Interface Specification (DOCSIS)
Standards and specifications that define protocols for the delivery of high-speed Internet service over hybrid fiber/coax (HFC) networks.

Digital Television (DTV)
The generic term for television systems employing digital, rather than analog technology. All high definition television (HDTV) is digital, but not all DTV is high definition. DTV transmission offers the advantages of compression for efficiency of bandwidth utilization, improved error performance for improved picture and sound quality, and more effective network management and control.

Digital Video Broadcast (DVB)
An industry-led consortium of over 200 broadcasters, manufacturers, network operators, software developers, regulatory bodies across 35 countries. DVB standards development for digital TV standards was started in 1991.

Ethernet
Standardized as IEEE 802.3, Ethernet is the most widespread local area network (LAN) technology in use operating at data rates from 10 megabits per second (Mbps) to 10 gigabits per second (Gbps).

Fiber-to-the-Home (FTTH)
Network topology where fiber-optic cable extends from the network’s point of origin, such as the headend, hub site, or central office (CO), to the customer premises.

Forward Error Correction (FEC)
A process by which additional data is coded with information data that enables the receiver to detect and correct some classes of errors that occur during transport.

High-Speed Data (HSD)
Broadband cable term used to reference a connection to the Internet supplied by the broadband cable operator, connection speed can vary from 1 Mbps to over 10,000 Mbps (10 gigabits per second) and higher.

Hybrid Fiber/Coax (HFC)
A broadband cable network architecture that uses both fiber-optic and coaxial cable.

Institute of Electrical and Electronics Engineers (IEEE)
The world’s largest technical professional association composed of engineers, scientists, and allied professionals dedicated to advancing innovation and technological excellence for the benefit of humanity via publications, conferences, technology standards, and professional and educational activities.

Integrated Services Digital Network (ISDN)
An early form of high-speed data service over dedicated phone lines but provides end-to-end digital connectivity, and it distinguishes itself from other services by guaranteeing bandwidth and allowing users to simultaneously utilize voice and data applications.

International Organization for Standardization (ISO)
A group of national standards organizations from many countries including the American National Standards Institute (ANSI) that develop voluntary, consensus-based, market relevant International Standards.

International Telecommunication Union (ITU)
The leading publisher of telecommunications technology, regulatory, and standards information.

Internet Engineering Task Force (IETF)
An international organization with a stated mission to produce high quality, relevant technical and engineering documents that influence the way people design, use, and manage the Internet.

Internet Protocol (IP)
A unique binary number that is assigned to Internet protocol (IP) network connected devices to precisely identify the device on the network or Internet.

Internet Protocol Version 4 (IPv4)
The legacy IP address scheme in which a unique 32-bit address is assigned to each device connected to an IP-based network.

Internet Protocol Version 6 (IPv6)
A standardized IP address scheme in which a unique 128-bit address is assigned to each device connected to an IP-based network.

Internet Service Provider (ISP)
A company that provides Internet access and related services, such as website building and virtual hosting, to individuals and companies.

Logical link control (LLC)
The part of the Data Link Layer in a network that brings various topologies together in a common format.

Low-Density Parity-Check (LDPC)
A forward error correction coding scheme that requires complex algorithms for decoding.

Management Information Base (MIB)
A simple network management protocol (SNMP) data structure used for storing and retrieving information to and from network elements.

Maximum Downstream Throughput (bits per second [bps]
The number of binary bits transmitted per second is measured in bps. For example, common modem speeds are 28,800 bps and 56,000 bps. Another way of writing 28,800 bps is 28.8 Kbps, because “kilo” means 1,000.

Media Access Control (MAC) Layer
A sublayer that operates between the Physical Layer (Layer 1) and the Data Link Layer (Layer 2) specified in the Open Source Interconnect (OSI) protocol stack to control access of the devices connected to the shared network.

Multimedia terminal adapter (MTA)
A standalone device that contains the interface to a telephone device, a modem interface, analog-to-digital coding and digital-to-analog decoding, and all signaling and encapsulation functions required to enable IP telephony service.

Noise Funneling
Noise arising from many sources traveling upstream into the headend from diverse paths.

Open Systems Interconnection (OSI) reference model
An architectural model for how digital information should be transmitted between any two points in a data communications network.

Orthogonal Frequency Division Multiplexing (OFDM)
A transport technique in which a number of closely spaced subcarriers are modulated with a digital signal at a low symbol rate. The subcarriers are then multiplexed so their phase is 90 degrees (orthogonal) to one another onto a single channel before transport.

Operations Support System (OSS)
Processes that provide back-office management for day-to-day functioning of the data network. These administrative processes are controlled by software on servers located at the headend or a hub.

Proactive Network Maintenance (PNM)
A CableLabs developed technology that enables broadband cable operators to identify and measure HFC network impairment using DOCSIS modem pre-equalization data.

Public Switched Telephone Network (PTSN)
The entire interconnection of all phone companies comprised of long distance, wireless, local, and international services.

Quadrature Amplitude Modulation (QAM)
A modulation technique for transporting digital information using a combination of amplitude modulation (AM) and phase modulation (PM).

Quadrature Phase Shift Keying (QPSK)
A digital modulation technique that combines two binary phase shift keying (BPSK) signals 90º out-of-phase.

Quality of service (QoS)
A guarantee of consistent, predictable data delivery service provided through a set of measurements or parameters that satisfy customer application requirements.

Reed-Solomon (RS)
A type of forward error correction code that adds parity bit data to the data stream.

Synchronous Code Division Multiple Access (S-CDMA)
A coded network access technique in which the data is coded and spread across the spectrum using an algorithm that places the data in an orthogonal pattern that enables the receiver to identify and decode data that is received simultaneously.

T-1
Data service used to transmit data or voice. A telephone carrier designation that is equal to 24 separate voice channels where 24 conversations can occur over the same circuit at the same time providing a data rate of 1.544 megabits per second (Mbps). For data services, 1.54 Mbps is possible both upstream and downstream.

Time Division Multiple Access (A-TDMA)
A time division multiple access (TDM) protocol with enhancements that include improved forward error correction (FEC) and ingress cancelation.

Tree-and-Branch
Legacy architecture of a coaxial cable network in which signals from the headend travel through a single trunk cable from which the signal is split and distributed into different areas: Resembling how a tree has a trunk with progressively smaller branches and limbs.

Time Division Multiple Access (TDMA)
A subset of time division multiplexing (TDM) in which multiple clients are granted admission to a common transport medium in order to transmit their signals at an allocated time on the same frequency or channel.

Voice over Internet protocol (VoIP)
The process of delivering telephone calls over the Internet rather than through the traditional switched-circuit telephone system.

Wi-Fi
The registered name for devices and networks that utilize the IEEE 802.11 wireless local area network (LAN) standard to exchange data and connect to the Internet.