Media Access Control. The lower portion of the datalink layer. As defined by the IEEE, the lower of the two
sublayers of the OSI reference model data link layer. The MAC sub-layer is concerned with media access
issues, such as whether token passing or contention is used
The hardware address of a device connected to a shared media.
A mail gateway that forwards electronic mail between two or more networks while ensuring that the
messages it forwards meet certain administrative criteria. A mail bridge is simply a specialized form of mail
gateway that enforces an administrative policy with regard to what mail it forwards.
Part of an electronic mail delivery system which allows a message to be delivered to a list of addressees.
Mail exploders are used to implement mailing lists. Users send messages to a single address (e.g.,
email@example.com) and the mail exploder takes care of delivery to the individual mailboxes in
A machine that connects two or more electronic mail systems (especially dissimilar mail systems on two
different networks) and transfers messages between them. Sometimes the mapping and translation can be
quite complex, and generally it requires a store-and-forward scheme whereby the message is received from
one system completely before it is transmitted to the next system after suitable translations.
A program which handles mailing list maintenance such as adding and removing addresses from mailing
Metropolitan Area Network. A data network intended to serve an area approximating that of a large city.
Term applied to packets that turn up unexpectedly on the wrong network because of bogus routing entries.
Also used as a name for a packet which has an altogether bogus (non-registered or ill-formed) Internet
Media Attachment Unit. This is the device that connects the AUI port on a host system to the rest of the
Multicast Backbone. A collection of Internet routers that support IP multicasting. The MBONE is used as a
"broadcast (actually multi-cast) channel" on which various public and private audio and video programs are
Mil ions Bits of information transmitted Per Second.
The Layer 3 information that is passed between the CPE and SPCS for signalling.
(MD-2, MD-4, MD-5) Message digests are algorithmic operations, generally performed on text, which
produce a unique signature for that text. MD-2, described in RFC 1319; MD-4, described in RFC 1320; and
MD-5, described in RFC 1321 all produce a 128-bit signature. They differ in their operating speed and
resistance to crypto-analytic attack. Generally, one must be traded off for the other. See PGP, DES, RSA.
Message Handling System. The system of message user agents, message transfer agents, message
stores, and access units which together provide OSI electronic mail. MHS is specified in the CCITT X.400
Management Information Base. A collection of objects that can be accessed via a network management
protocol. (Most people today think it means "Men in Black")
Mid-level networks (a.k.a. regionals) make up the second level of the Internet hierarchy. They are the transit
networks which connect the stub networks to the backbone networks.
MILitary NETwork. Originally part of the ARPANET, MILNET was partitioned in 1984 to make it possible for
military installations to have reliable network service, while the ARPANET continued to be used for
Multi-purpose Internet Mail Extensions. The standard for multimedia mail contents in the Internet suite of
Modem stands for Modulator/Demodulator. A modem transmits computer data over the telephone network.
On the sending sided it converts digital data to analog for transmission over an analog line (such as the
telephone network). On the receiving side it converts the analog transmission back to digital data.
MOSPF Multicast Open Shortest-Path first.
Moving Picture Experts Group. Commonly refers to the international standard for digital video and audio
Multiprotocol Over ATM. An ATM Forum specification that defines how ATM traffic is routed from one virtual
LAN to another. MPOA is key to making LAN emulation, Classical IP over ATM, and proprietary virtual LAN
schemes inter-operate in a multi-protocol environment.
MRRU Maximum Receivable Reconstructable Unit
Message Transfer Agent. An OSI application process used to store and forward messages in the X.400
Message Handling System. Equivalent to Internet mail agent.
Maximum Transmission Unit. The largest possible unit of data that can be sent on a given physical medium.
Example: The MW of Ethernet is 1500 bytes.
A special form of broadcast where copies of the packet are delivered to only a subset of all possible
A computer connected to more than one physical datalink. The data links may or may not be attached to
An optical fiber which allows several rays of light to pass. It is less expensive than single mode fiber but it
This equipment al ows multiple signals to be transmitted over the same physical media. There are Time
Division Multiplexers and Frequency Division Multiplexers.
A communications line having multiple cable access points.
Mail Exchange Record A DNS resource record type indicating which host can handle mail for a particular
9. Symposium für Neonatologie und pädiatrische Intensivmedizin Sachsen-Anhalt A b s t r a c t s __________________________________________________________________________ Neonatale Krampfanfälle G. Jorch __________________________________________________________________________________________Zerebrale Anfälle bei Neugeborenen (Frühgeborenen und Reifgeborenen) zeigenalterstypis
Information About Tinnitus: General Information and Prevalence Kimberly Langer-Roedel, M.S.--F.A.A.A. Clinical Audiology Consultant The EAR Foundation of Arizona Tinnitus can be defined as ringing in the ears, or other head noises that occur independentfrom an external noise source (Yost, 1994). Studies conducted by the National Center forHealth Statistics estimate that 32% of the ge