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Glossary of broadband terminology: M

M13: A piece of telecommunications equipment which multiplexes (combines )28 DS-1 signals into a single DS-3 signal, commonly used for concentrating traffic for economies of transmission. See also Multiplexer.
Main Distribution Frame: Central point where all local loops terminate in the CO.
MAN: Metropolitan Area Network
Typically used for large corporations, universities and councils spread over a wide district.
Management Information Base: A database of objects that can be monitored by a network management system. Both SNMP and RMON use standardized MIB formats that allow any SNMP and RMON tools to monitor any device defined byan MIB.
MDU: .
Mean Time Between Failure: MTBF ratings are measured in hours and indicate the sturdiness of hard disk drives and printers. Typical disk drives for personal computers have MTBF ratings of about 300,000 hours.This means that of all the drives tested, one failure occurred every 300,000 hours of testing. However, this is rather meaningless since most disk drives are tested only a few hours, so it would be unlikely for a failure to occur during this short testing period. A more useful gauge of a device's lifetime is how long a warranty the manufacturer offers.
Media Access Control: A method of controlling access to a transmission medium (e.g., Ethernet, Token Ring, and FDDI).
Megabits Per Second: A measure of bandwidth capacity or transmission speed. It stands for a million bits per second.
Metropolitan Area Ethernet: A MAE is a NAP where ISPs can connect with each other. The original MAE was set up by a company called MFS and is based in Washington, DC. Later, MFS built another one in Silicon Valley, dubbed MAE West. In addition to the MAEs from MFS, there are many other NAPs. Although MAE refers really only to the NAPs from MFS, the two terms are often used interchangeably.
Metropolitan Area Network: A data communication network typically covering the geographic area of a city; a communications network that is usually larger than a LAN but smaller than a WAN. See Campus Area Network, Local Area Network, and Wide Area Network.
Metropolitan Serving Area: A regional area served by a provider which is classified based on the metropolitan coverage area.
Minimum Point Of Entry: The closest practical point to where the carrier facilities cross the property line or the closest practical point to where the carrier cabling enters a multiunit building or buildings.
Mobile Telephone Switching Office: A generic name for the main cellular switching center which supports multiple base stations.
Modem: A term which is actually based on the function of the device itself -- a MOdulator/DEModulator. A modem converts analog waveforms into digital data and vice versa. In xDSL, the device that is at each end of the xDSL circuit is being generically referred to as a modem. See also Demodulation and Modulation.
Moderate Speed Digital Subscriber Line: A slower variant of HDSL, MDSL is widely used in pairgain systems to increase the effective capacity of a copper loop.
Modulation: The process whereby an electrical carrier wave is altered to facilitate the transmission of a signal.
Motion Picture Experts Group: This is an industry organization whose goalis to develop standards and specifications for the encoding, transmission,and unencoding of video information over various media and network technologies. See also MPEG1 and MPEG2.
Movies on Demand: See Video on Demand.
MPEG1: Compression scheme for full motion video. Compression algorithm introduced by MPEG in 1991, the common goal of MPEG is to compress 7.7 Meg down to about 150 Kbytes. MPEG1 is designed to provide a resolution of 352 by 240 pixels at 30 frames per second.
MPEG2: Video compression standard selected by MPEG. Designed to provide a resolution of 720 by 480 pixels at 30 frames per second. Likely to be the leading compression algorithm for a range of video applications including video on demand.
Multichannel Multipoint Distributed Service: Also known as wireless cable. MMDS is a pay television delivery system that delivers up to 33 channels of video programming via microwave transmission. MMDS systems consist of four parts (1) a head end, located a top a tall building, where broadcast and cable TV signals are received and converted to microwave radio signals for retransmission. They are sent using (2) an omnidirectional transmit antenna to subscribers who are equipped with (3)receiving antennas which convert the microwave frequencies to lower frequencies, and send them to (4) a TV or VCR. MMDS is line of sight transmission; the receiving antenna must have unobstructed view of the transmitting antenna. MMDS systems operate a band of radio spectrum that ranges from 2.5 billion cycles a second to 7 billion. That band can only be used for broadcast (one-way) communications.
Multiple System Operator: A company that operates more than one cable TV system.
Multiplexer: A MUX is a device that allows the transmission of multiple data streams over a common medium. Several communications paths or channels may be either permanently or dynamically established over the medium to accomplish this. See also Channel.