100VG-AnyLAN
100VG-AnyLAN is a 100-Mbps Ethernet technology standard that directly competes with 100BaseT Ethernet. The IEEE 802.12 committee is currently investigating this technology. The access method used by this standard is different than the CSMA/CD method used by 10-Mbps Ethernet and Fast Ethernet; however, the MAC frame format is the same. The new access method is called "demand priority."

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abend
Abend is short for "ABnormal END" and traditionally means a processing error that stops, or crashes, an OS.

adapter
An adapter is a term used to identify the computer card that fits into the computer bus. One type of adapter is a NIC. A NIC provides a connection (interface) to the networking media for sending information across a network.

Address Resolution Protocol (ARP)
Unit 3 and 9: ARP is the protocol used by IP (as in TCP/IP) for address resolution. Address resolution refers to the ability of a station to resolve another station's MAC (hardware) address given its IP address.
Unit 5: ARP is a protocol that allows a host to use a logical (network) address to obtain the hardware (NIC, MAC) address for a remote station.

American National Standards Institute (ANSI)
ANSI is a national voluntary organization that develops and publishes standards for data communications, programming languages, magnetic storage media, the OSI model, office systems, and encryption.

American Standard Code for Information Interchange (ASCII)
ASCII is one of the two most widely used codes to represent characters, such as keyboard characters (EBCDIC is the other). ASCII uses 7 bits for the 128 elements it represents. For example, the ASCII representation of the character "A" is decimal numeral 65, hexadecimal 41, or binary 100 0001. See EBCDIC.

AppleTalk Filing Protocol (APF)
AFP is the protocol used in Apple networks for retrieving and storing files across a network.

application programming interface (API)
In general, an API consists of computer processes used by applications to carry out lower level tasks performed by a computer's OS. In networking, an API provides applications with a consistent method of requesting services from a network. One of the most common APIs used in networking is NetBIOS.

ATM Forum
The ATM Forum is an international industry organization that promotes the use of ATM by facilitating a rapid convergence of interoperability specifications.

attempt counter
An attempt counter is a value that records the number of times an Ethernet NIC has attempted to transmit the same frame. The NIC discards a frame after 16 consecutive collisions occur for the same transmission attempt.

attempt limit
An attempt limit is the maximum number of times (16) that an Ethernet NIC will attempt to retransmit a frame after a collision.

availability
Availability refers to the amount (or percentage) of time a given network or component in a network (such as a host or server) is available to carry out its intended task.