A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Ma Bell - AT&T Reference, which gave birth to the Baby Bells / RBOC's.
Main Distribution Frame - Aka Distribution Frame. Termination point for all wire, coax, or fiber optic for a network, placed as close to central office or PBX as possible.
Main PBX - Small, local telephone office or device with the same functionality; directly connected to a tandem switch via an access trunk group.
Management Information System (MIS) - Aka IS (Information Systems). Company department, responsible for data and voice communications & processing.
Manual Tie Line - Private communication channel which requires the assistance of an attendant at both ends of the circuit in order to complete the call.
Mean Time To Repair (MTTR) - Average time required to restore a customer's service after a network failure.
Mega (M) - Mega is the prefix for million. Example - 20 megabytes = 20,000,000 bytes.
Megabits per Second (Mbps) - One million bits per second.
Megabytes (MB) - One million bytes.
Megahertz (Mhz) - One million hertz, equivalent to one million cycles per second.
Message Telephone System (MTS) - (1) Generic name for switched long distance service offered by all interexchange carriers. (2) Offering for which a charge is made in accordance with a measured amount of usage referred to as message units.
Metropolitan Area Network (MAN) - A computer network, incorporating the local telephone company facilities to communicate, connecting other LAN's or computers together (usually via T1 lines).
Microsoft Certified Systems Engineer (MCSE) - Microsoft-based training, done either by Microsoft or one of their trading partners, incorporating Microsoft networking products - especially enterprise networking and Microsoft database applications.
Microwave - Terrestrial microwave line between two radio transceivers using parabolic dish antennas pointed directly at each other - carrying bandwidths that include DS1, DS2, DS3, STS1, and OC1, with ranges up to 50 miles (depending on weather, antenna size, and power emitted).
Mini T1 - Aka Mini-T. A way to connect a T1 circuit from one side of a building to another, such as a T1 cross connect running between tow DSX panels within a central office.
Mobile Telephone Switching Office (MTSO) - Used by cellular carriers to route and receive customer calls. May be interconnected to the LEC or directly to an interexchange carrier's (IXC) network.
Modem (Modulate/Demodulate) - Equipment that transmits digital information over a telephone line (either standard POTS line or private 56K circuit). Modems modulate the digital information before transmission.
Multicast - A method of transmitting data to be received and used by multiple network devices, with user group addresses ranging from 224.0.0.0 to 239.255.255.255. Also known as Class-D IP Addresses.
Multicast Address - A single address, that transmits to be received and used by multiple network devices.
Multicast Address Resolution Server (MARS) - IP multicast supporting mechanism, serving a group of nodes/clusters that are configured with the ATM address of the MARS. Supports through multicast messages of overlaid point-to-multipoint connections or through multicast servers.
Multihop - Microwave links requiring two or more links to get to a destination - allows link to extend distance, as well as move the link path around buildings or mountains.
Multimode - Utilizing a larger core than single mode fiber optic, Multi mode accepts not only more light, but more frequencies of light - good for short distances such as LAN's. Single mode has a smaller core (5 to 15 microns vs. multi-mode's 50 to 100 microns) - but is better for longer distances and SONET applications.
Multiplex - Encoding of two or more digital signals or channels into one to save money. For example, an encoded T1 has 24 channels into 1 using frequency-division multiplexing; where it would take 24 lines needing 24 pairs of wire, multiplexing drops it down to 2 lines.
Multiplexer (MUX) - Hardware device that allows handling of multiple variable speed signals over a single, higher speed channel.
Native Protocol - Format of the LAN, transmitted over a WAN. If a LAN is Ethernet-based, and connects to a remote LAN on a frame-relay network, Ethernet is the native protocol (and the connection protocol is frame-relay).
Network - A group of devices that use a set of rules / protocols to communicate back and forth via copper wire, fiber optic, coax, radio or light.
Network Basic Input/Output System (NetBIOS) - Within a Novell NetWare protocol stack, a set of instructions that extend a PC's BIOS instructions to communicate beyond its own hardware and into the network.
Network Interface(NI) - Aka Standard Network Interface, Demarcation Point, or Lightning Protector - contains carbons to protect a phone line from overload, and acts as a separation point between the customer and the phone company's inside wire.
Network Interface Card (NIC) - A piece of hardware for a computer that provides the electronic and physical interface for the network of its type. Plugs into a motherboard via an ISA or PCI expansion socket/slot.
Network Layer - Layer in a communications protocol. For example, Network layers do the job of routing/switching data transmitted within the protocol.
Network Node Interface (NNI) - Used in ATM, provides 4096 virtual paths and 65,536 virtual connections within each path - equals up to 268,435,456 channels between two ATM networks, switches, or users - physically connected over a UNI.
Network Numbering Exchange (NNX or NXX) - Three digit central office (CO) identification code; N is a digit two through nine, and x is a digit zero through nine. Originally an NNX, now in the form of NXX due to an expansion by CO's where zero and one may appear as second digits
Network Operations Center (NOC) - Where large or public telephone networks are management, maintained, and monitored.
Network Ring Again - PBX feature that allows a caller, after encountering a busy signal, to be notified when the called line becomes free; provided the option of automatically reinstating the call.
Network Service Provider (NSP) - Companies that provide services such as ADSL, HDSL, ATM, Frame Relay, Internet Access, or other services. Usually use their own switching equipment, or they lease the equipment - and they normally utilize a local telco or CAP for the local loop. They link nodes via high capacity circuits. They also may have interconnection agreements with other telecom companies.
Network Termination Equipment (NTE) - Aka DCE or DTE (Data Communications Equipment, or Data Termination Equipment).
Network Trunks - Circuits connecting switching centers.
Node - Any device or entity, attached to a network, that possesses a Media-Access Control (MAC) address. In a WAN, a node is a switch or router serving as a control point in a network, incorporating routing protocols in order to route traffic and communicate network communications throughout the network. In Voice traffic - a device with switching capability or a central office.
Non-wireline carrier - (1) Result of FCC regulation licensing two carriers in areas designated metropolitan statistical area (MSA) and rural service area (RSA). (2) Independent company that is unaffiliated with a local telephone company that serves a MSA or RSA.
North America Number Plan (NANP) - See area code.
Numbering Plan Area (NPA) - (1) Geographic boundary within which no two telephone numbers have the same seven-digit number. "N" is any number between two and nine, "P" is always one or zero, and "A" is any number excluding zero. (2) Area code.
Number Portability - The ability to take your phone number with you, whether you move geographic location, or switch between communications service providers.