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8237 Hub Installation and Planning Guide

address resolution protocol (ARP). A protocol that
dynamically maps between Internet addresses,
baseband adapter addresses, X.25 addresses, and
token-ring adapter addresses on a local area network.

agent. See Simple Network Management Protocol
(SNMP) agent.

ANSI. American National Standards
Institute.application. A collection of software
components used to perform specific types of user-
oriented work on a computer.ASCII. American National
Standard Code for Information Interchange. The
standard code, using a coded character set consisting
of 2-bit coded characters (8 bits including parity check),
that is used for information interchange among data
processing systems, data communication systems, and
associated equipment. The ASCII set consists of
control characters and graphic characters. (A)

Note: IBM has defined an extension to ASCII code
(characters 123-255).

attach. To make a device a part of a network
logically.attaching device. Any device that is
physically connected to a network and can
communicate over the network.AUI. Attachment unit
interface.

authentication. (1) In computer security, verification of
the identity of a user or the user’s eligibility to access
an object. (2) In computer security, verification that a
message has not been altered or corrupted. (3) In
computer security, a process used to verify the user of
an information system or protected resources. (4) A
process that checks the integrity of an entity.

authentication entity. In the Simple Network
Management Protocol (SNMP), the network
management agent responsible for verifying that an
entity is a member of the community it claims to be in.
This entity is also responsible for encoding and
decoding SNMP messages according to the
authentication algorithm of a given community.

authentication failure. In the Simple Network
Management Protocol (SNMP), a trap that may be
generated by an authentication entity when a
requesting client is not a member of the SNMP
community.

auto-partition. In Ethernet repeaters, to shut off traffic
in and out of a port when the port detects excessive an
excessive frequency or duration of collisions. Auto-
partitioned ports continue to transmit and receive, and
when they are successful in either in a specified
amount of time, they reconnect to the network
automatically.

back pressure. A method of preventing network
packets being transmitted onto a network segment by
sending a jamming signal.

bandwidth. (1) The difference, expressed in hertz,
between the highest and the lowest frequencies of a
range of frequencies. For example, analog
transmission by recognizable voice telephone requires
a bandwidth of about 3000 hertz (3 kHz). (2) The
bandwidth of an optical link designates the information-
carrying capacity of the link and is related to the
maximum bit rate that a fiber link can support.

baud. (1) A unit of signaling speed equal to the
number of discrete conditions or signal events per
second; for example, one baud equals one-half dot
cycle per second in Morse code, one bit per second in
a train of binary signals, and one 3-bit value per second
in a train of signals each of which can assume one of
eight different states. (A) (2) In asynchronous
transmission, the unit of modulation rate corresponding
to one unit interval per second; that is, if the duration of
the unit interval is 20 milliseconds, the modulation rate
is 50 baud. (A)

BBS. Bulletin Board System.

binary. (1) Pertaining to a system of numbers to the
base two; the binary digits are 0 and 1. (A) (2)
Pertaining to a selection, choice, or condition that has
two possible different values or states. (I) (A)

bit. Either of the binary digits: 0 or 1.

bit-time. (1) The time required to transmit 1 bit on the
network. For example, the IBM PC Network bit-time
equals 500 nanoseconds (ns) and the Fast Ethernet
bit-time equals 10 ns. (2) The reciprocal of the line data
rate (or network data transfer rate).

BNC. A connector used with some coaxial cables.

BootP. Bootstrap Protocol.

Bootstrap Protocol (BootP). A protocol in the TCP/IP
suite that permits a station to transmit a request for an
IP address to a server and permits the server to assign
a station an IP address based on the station’s media
access control (MAC) address. Together with the
Trivial File Transfer Protocol (TFTP), BootP can also
be used to send files.

bps. Bits per second.

bridge. (1) An attaching device that connects two LAN
segments to allow the transfer of information from one
LAN segment to the other. A bridge may connect the
LAN segments directly by network adapters and
software in a single device, or may connect network
adapters in two separate devices through software and
use of a telecommunications link between the two
adapters. (2) A functional unit that connects two LANs
that use the same logical link control (LLC) procedures