M

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MAC (Medial Access Control) Address

This is a network interface card's hardware address; every NIC comes from the factory with a MAC address burned into it. A MAC address consists of a unique 48-bit address which is expressed in units of 4 bits (called nibbles) as a series of numerals in the range of zero through fifteen.

MAC Address Filtering

This term refers to the ability of a network manager to block all incoming packets from a specific source or sources. The MAC address is a unique series of numbers and letters assigned to every networking device. With MAC address filtering enabled, wireless network access is provided solely for wireless devices with specific MAC addresses. This makes it harder for a hacker to access a wireless network using a random MAC address.

MAC Protocol Data Unit (MPDU)

The unit of data in an IEEE 802 network that two peer MAC entities exchange across a physical layer.

MAC (Medium Access Control) Sublayer

One of two sublayers that make up the Data Link Layer of the OSI model. The MAC sublayer is responsible for moving data packets to and from one Network Interface Card to another across a shared channel.

See also OSI (Open System Interconnection) Model.

MAN

See Metropolitan Area Network (MAN).

Mbps (Megabits per Second)

A term that refers to one million bits per second; as such Mbps is a standard measure of data rate and transmission capacity. Also referred to as mbits/s.

Megahertz (MHz)

One million cycles per second. A common unit used in measurement of signal bandwidth—digital and analog.

See also Hertz (Hz).

Message Integrity Check (MIC)

A security method used to prevent bit-flip attacks on encrypted packets. During a bit-flip attack, an intruder intercepts an encrypted message, alters it slightly, retransmits it, and the receiver accepts the retransmitted message as legitimate. The client adapter's driver and firmware must support MIC functionality, and MIC must be enabled on the access point.

Metropolitan Area Network (MAN)

Two or more LANs linked together so resources between the LANs can be shared.

See also Local Area Network (LAN).

MIC

See Message Integrity Check (MIC).

Microprocessor

This term refers to a chipset that handles the logic operations (e.g. addition, subtraction and copying) in a computer. A set of instructions in the chip design tells the microprocessor what to do, but different applications can give instructions to the microprocessor as well. Chip speeds are measured in megahertz (MHz), so a 120 MHz chip is twice as fast as a 60 MHz chip. However, that doesn't mean a 120 MHz computer will run all tasks twice as fast as a 60 MHz computer, as speed is also influenced by other factors, such as the design of the software running on the machine, the operating system being used, and so forth.

See also Chip.

See also Megahertz (MHz).

Middleware

A term used to describe software products designed to serve as the "glue" between two otherwise separate applications so that data can pass between the two applications.

Mobile IP

An IETF communications protocol designed to allow users with mobile computing devices to move from one network to another while maintaining their permanent IP address. Mobile IP is an enhancement of the Internet Protocol (IP) that adds mechanisms for forwarding Internet traffic to mobile devices when they are connecting through other than their home network.

Mobile Identification Number (MIN)

This term refers to a wireless carrier's identifier (i.e. phone number) for a phone in its network. The MIN is meant to be changeable, since the phone could change hands or a customer could move to another city.

Mobile Switching Centre

See Mobile Switching Office (MSO).

Mobile Switching Office (MSO)

A switch that provides services and coordination between mobile users in a network and external networks. Also known as Mobile Telephone Switching Office (MTSO), and Mobile Switching Centre (Europe).

Mobile Telephone Switching Office (MTSO)

See Mobile Switching Office (MSO).

Modem

Short for MOdulator/DEModulator, a modem is a system that converts computer data into signals that can be transmitted over telephone. If the data is to be sent over a POTS (Plain Old Telephone Service) line (versus DSL or Cable), the sending modem converts digital data to analog for transmission and on the receiving side another modem converts the analog transmission back to digital data.

MPDU

See MAC Protocol Data Unit (MPDU).

MPEG (Moving Pictures Experts Group)

A standard for compressing sound and video files into an attractive format for downloading or streaming across the Internet. The MPEG-1 standard streams video and sound data at 150 Kbps, while MPEG-2 provides compressed video that can be shown at near-laserdisc clarity with a CD-quality stereo soundtrack. Digital satellite services and DVD use MPEG-2.

MP3

The term refers to a specific type of codec (an algorithm that encodes and decodes or compresses and decompresses various types of data) that compresses standard audio tracks into much smaller sizes without significantly compromising sound quality.

MSO

See Mobile Switching Office (MSO).

MTSO

See Mobile Telephone Switching Office (MTSO).

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