B.ISDN Backbone backbone network
back channel backdoor route back end
backoff back pressure backward channel
backward learning Balanced balanced configuration
balun BAMP
bandwidth bandwidth reservation
Bang Path BARRNet Baseband
basic rate interface Baud BBLT
BBN BBS BCD
BCP
B channel BDOS BDSL
beacon
Bellcore Bellman-Ford routing algorithm BELnet
BER BERT best-effort delivery
BGP BIOS Big-Endian
binary binary file BIND
BinHex biphase coding Bipolar
bisync Bit BITBLT
bit error rate Bit Interleaving/Multiplexing BITFTP
BITNET bit-oriented protocol bit rate
black hole blind carbon copy BLMC
blocking block multiplex. chan. BMP
BNC connector BOC
BOF boot BOOTP
Boot PROM border gateway Bounce
boundary function BPDU BRI
bps Bridge bridge-group
bridge number Broadband Broadcast
broadcast address broadcast search Broadcast Storm
Brouter browser BSC
BSD BT BTNet
Btw
Buffer Bus bus and tag channel
bus topology bypass mode Byte
byte-oriented protocol byte reversal
B.ISDN Broadband ISDN.
Communication standards being developed by the CCITT to handle hight-bandwidth
applications such as video.
BISDN will use ATM technology over
SONET-based transmission circuits
to provide data rates of 155 Mbps to 622 Mbps and beyond. See also BRI,
ISDN, and PRI,
Asynchronous Transfer Mode.
Backbone The top level
in a hierarchical network. Stub and transit networks which connect to the
same backbone are guaranteed to be interconnected. See also: stub
network, transit network. Source:
[RFC 1983]
backbone network A network
acting as a primary conduit for traffic that is often both sourced from,
and destined for, other networks.
back channel A channel
used for sending data in the opposite direction as the primary channel.
Back channels are frequently used to send control informtion. Using back
channels, information can still be delivered even though the primary channel
may be malfunctioning. Also called backward channel or reverse
channel.
backdoor route Route
to a nonlocal network specified by an AGP that should be used by a border
router. Cisco routers allow specification of backdoor routes using a variation
of the network router subcommand.
back end A node or software
program that provides services to a front end. See also client and server.
backoff The (usually
random) retransmission delay enforced by contention media access control
protocols after a node that wanted to transmit sensed carrier on physical
medium.
back pressure Propagation
of network congestion information upstream through an internetwork.
backward learning Process
through which information is surmised by assuming symmetrical network conditions.
For example, assume node A receives a packet from node B through intermediate
host C. A backward learning routing algorithm will then assume that A can
optimally reach B through node C.
Balanced A transmission
line in wich voltages on the two conductors are equal in magnitude, but
opposite in polarity with respect to ground (with opposite polarities).
balanced configuration In
HDLC, a point-to-point network configuration with two combined stations.
balun Balanced, unbalanced.
Device used for matching impedance between a balanced and an unbalanced
line, usually twisted pir and coaxial cable.
BAMP (Build Ada Main Program).
Bandwidth Technically,
the difference, in Hertz (Hz), between the highest and lowest frequencies
of a transmission channel. However, as typically used, the amount of data
that can be sent through a given communications circuit. Source: [RFC
1983]
bandwidth reservation In
circuit-switched lines, a feature in which call bandwidth can be reserved
for high-bandwidth or high-priority calls.
Bang Path A series
of machine names used to direct electronic mail from one user to another,
typically by specifying an explicit UUCP path through which the mail is
to be routed. See also: Email Address,,
Mail Path, UNIX-to-UNIX
CoPy. Source: [RFC
1983]
BARRNet Bay Area Regional
Research Network. A network serving the San Francisco Bay Area. BARRNet's
backbone is composed of four University of California campuses (Davis,
Berkeley, Santa Cruz and San Francisco), Stanford University, Lawrence
Livermore national Lab, and Nasa Ames Research Center.
Baseband A transmission
medium through which digital signals are sent without complicated frequency
shifting. In general, only one communication channel is available at any
given time. Ethernet is an example of a baseband network. See also: Broadband,
Ethernet. [Source: NNSC]
Baud Unit of signalling
speed equivalent to the number of discrete conditions or events per second.
If each signal event represents only one bit condition, baud rate equals
bps (bit per second).
BBLT (Bus BLock Transfer).
BBN (Bolt, Beranek,
and Newman, Inc.). A Massachusetts company responsible for the development
and maintenence of the ARPANET (and
later, Internet) core gateway system.
BBS (Bulletin Board System).
A computer, and associated software, which typically provides electronic
messaging services, archives of files, and any other services or activities
of interest to the bulletin board system's operator. Although BBS's have
traditionally been the domain of hobbyists, an increasing number of BBS's
are connected directly to the Internet, and many BBS's are currently operated
by government, educational, and research institutions. See also: Electronic
Mail, Internet, Usenet.
Source:[NWNET]
BCD (Binary-Coded Decimal).
Coding decimal numbers in binary form so that they can be processed effectively
by a personal computer.
BCP (Best Current Practices) The
newest subseries of RFCs which are written to describe Best Current Practices
in the Internet. Rather than specifying a protocol, these documents specify
the best ways to use the protocols and the best ways to configure options
to ensure interoperability between various vendors' products. BCPs carry
the endorsement of the IESG. See also: Request
For Comments, Internet Engineering Steering
Group. Source: [RFC
1983].
B channel In ISDN,
a full-duplex, 64-Kbps channel employed to send user data.
BDOS (Basic Disk Operating
System).
BDSL Same as VDSL
beacon A signal from
an IBM Token ring device indicating
a serious problem with the ring, such as a broken cable. Beacon frames
contain the address of the assumed down station.
Bellcore An organization
that performs research and development on behalf of the RBOC.
Bellman-Ford routing algorithm
See distance vector routing
algorithm.
BELnet (BELgian
Research Network) The BELNET research network is becoming
the pre-eminent communications network and a gateway to the R&D world
for the Belgian researcher.
BER (Basic Encoding Rules).
Standard rules for encoding data units described in ASN.1. Sometimes incorrectly
lumped under the term ASN.1, which properly refers only to the abstract
syntax description language, not the encoding technique. See also: Abstract
Syntax Notation One. Source: NNSC
BERT (Bit Error Rate Test/Tester).
A device used to test the bit error rate of a communications circuit. The
device checks for errors by comparing a received data pattern with a known
transmitted data pattern to determine transmission line quality.
best-effort delivery A
characteristic of network systems that do not use a sophisticated acknowledgment
system to guarantee reliable delivery of information.
BGP (Border Gateway Protocol).
Is an exterior gateway protocol defined in RFCs 1267
and 1268.
It's design is based on experience gained with EGP, as defined in STD
18, RFC
904, and EGP usage in the NSFNET Backbone, as described in RFCs 1092
and 1093.
See also: Exterior Gateway Protocol.Source:
[RFC1392]
BIOS (Basic Input/Output
System)
Big-Endian A format
for storage or transmission of binary data in which the most significant
bit (or byte) comes first. The term comes from "Gulliver's Travels" by
Jonathan Swift. The Lilliputians, being very small, had correspondingly
small political problems. The Big-Endian and Little-Endian parties debated
over whether soft-boiled eggs should be opened at the big end or the little
end. See also: Little-Endian.Source:
[RFC1208]
binary A numbering
system, in which each digit (from right to left) represents an increasing
power of 2 . As the base b=2, there is need for b enumerators, which commonly
is zero and one.
binary file A file
that contains codes which are not part of the ASCII
character set. A binary file can contain any type of information that can
be represented by an 8 bit byte - a possible 256 values.
BIND (Berkeley Internet
Name Domain). Implementation of a DNS server developed and distributed
by the University of California at Berkeley. Many Internet hosts run BIND,
and it is the ancestor of many commercial BIND implementations. See also:
Domain Name System. Source: [RFC
1983]
BinHex (BINary HEXadecimal)
-- a method for converting non-text files (non-ASCII) into ASCII. This
is needed because Internet e-mail can only handle ASCII
text.
biphase coding Bipolar
coding scheme originally developed for use in Ethernet. Clocking information
is embedded into and recovered from the synchronous data stream without
the need for separate clocking leads. The biphase signal contains no DC
energy.
Bipolar A signalling
method (used in T1/E1)
wich represents a binary "1" by alternating positive and negative pulses,
and binary "0" by absence of pulses.
Bit A contraction of "Binary
Digit", the smallest unit of information in a binary system. A bit represents
either a one or zero ("1" or "0").
BITBLT (BIT BLock Transfer).
bit error rate Percentage
of transmitted bits received in error.
Bit Interleaving/Multiplexing
A process used in time division multiplexing where individual
bits from different lower speed channel sources are combined (one bit from
one channel at a time) into one continuous higher speed bit stream.
BITFTP (BITNET FTP). Is
a BITNET FTP Server, allows users
of, bitnet and associated networks to access FTP
sites on the Internet.Source: EARN Association
BITNET An academic computer
network that provides interactive electronic mail and file transfer services,
using a store-and-forward protocol, based on IBM Network Job Entry protocols.
Bitnet-II encapsulates the Bitnet protocol within IP packets and depends
on he Internet to route them. Source: [RFC
1983]
bit-oriented protocol Class
of link-layer communication protocols that can transmit frames without
regard for frame content. Compared with byte-oriented protocols, bit-oriented
protocols are more efficient and more reliable, and they provide full-duplex
operation.
bit rate The speed
at which bits are transmitted, usually, expressed in bits per second (bps).
black hole Routing
term for an area of the network where packets enter but do not emerge,
due to observe conditions or poor system configuration within a portion
of the network.
blind carbon copy A copy
of a message which all persons on the Bcc: list receive. Recipients cannot
see who else has received the message: hence the term "blind".
BLMC (Buried Logic MacroCell).
blocking In a switching
system, a condition in which no paths are available to complete a circuit.
The term is also used to describe a situation in which one activity cannot
begin until another has been completed.
block multiplexer channel An
IBM-style channel that implemets the FIPS-60
channel, a U.S. channel standard. This channel is also referred to as the
OEMI channel and the 370 block multiiplexer, or block mux, channel.
BMP (Microsoft Windows Bitmap).
Also: (Benchmark Plan)
BNC connector Standard
connector used to connect IEEE 802.3]10Base
2 coaxial cable to a transceiver.
BOC (Bell Operating Company) More
commonly referred to as RBOC for Regional Bell Operating Company. The local
telephone company in each of the seven U.S. regions. Source: [RFC1208]
BOF (Birds Of a Feather) A
Birds Of a Feather (flocking together) is an informal discussion group.
It is formed, often ad hoc, to consider a specific issue and, therefore,
has a narrow focus. See also: Working
Group. Source: [RFC
1983]
boot This term derives from
`bootstrap loader', a short program that was read in from cards or paper
tape, or toggled in from the front panel switches. This program was always
very short (great efforts were expended on making it short in order to
minimise the labour and chance of error involved in toggling it in), but
was just smart enough to read in a slightly more complex program (usually
from a card or paper tape reader), to which it handed control; this program
in turn was smart enough to read the application or operating system from
a magnetic tape drive or disk drive. Thus, in successive steps, the computer
`pulled itself up by its bootstraps' to a useful operating state.
BOOTP The Bootstrap Protocol,
described in RFC
1542, is used for booting diskless nodes. See also: Dynamic
Host Configuration Protocol, Reverse
Address Resolution Protocol. Source: [RFC
1983]
BootPROM Boot Programmable
Read-Only Memory. A chip mounted on a printed circuit board used to provide
executable boot instructions to a computer device.
border gateway A router
that communicates with routers in other autonomous systems (AS).
Bounce The return of a
piece of mail because of an error in its delivery. Source: [ZEN].
boundary function A
capability of SNA subarea
nodes to provide protocol support for attached peripheral nodes. Typically
found in IBM 3745 devices.
BPDU (Bridge Protocol
Data Units). A spanning-tree protocol hello packet. See also PDU.
BPS (Bit Per Second). A measure
of data transmission rate in serial transmission. Also used to describe
hardware capabilities. (for example, a 9600 bps modem).
BRI (Basic Rate Interface).
The ISDN interface composed of two B
channels and one D channel
for circuit-switched communication of voice, data and video. See also BISDN
and ISDN.
Bridge A device which
forwards traffic between network segments based on datalink layer information.
These segments would have a common network layer address. See also: gateway,
router.
bridge-group Cisco
bridging subcommand that assigns network interfaces to a particular spanning-tree
group. Bridge-groups may be IEEE 802.1-or
DEC-compatible.
bridge number A number
that identifies each bridge in a source route-bridge LAN.
Parallel bridges must have a different bridge number.
Broadband A transmission
medium capable of supporting a wide range of frequencies. It can carry
multiple signals by dividing the total capacity of the medium into multiple,
independent bandwidth channels, where each channel operates only on a specific
range of frequencies. See also: baseband.
Source: [RFC
1983]
Broadcast A special
type of multicast packet which all nodes on the network are always willing
to receive. See also: multicast,
unicast. Source: [RFC
1983]
broadcast address An
address reserved for sending to all stations on a network simultaneously.
broadcast search Propagation
of a search request to all network nodes if the location of a resource
is unknown to the requester. See also directed search.
Broadcast Storm An
incorrect packet broadcast onto a network that causes multiple hosts to
respond all at once, typically with equally incorrect packets which causes
the storm to grow exponentially in severity. See also: Ethernet
meltdown. Source: [RFC
1983]
Brouter A device which
bridges some packets (i.e., forwards based on datalink layer information)
and routes other packets (i.e., forwards based on network layer information).
The bridge/route decision is based on configuration information. See also:
Bridge, router.
Source: [RFC
1983]
Browser A World Wide
Web client-that is, a software package
that permits you to look around the World
Wide Web (WWW). See also:URL.
BSC (Binary Synchronous Communication).
A character-oriented datalink protocol for half-duplex applications. Usually
referred to simply as bisync.
BSD (Berkeley Software Distribution).
Implementation of the UNIX operating system and its utilities developed
and distributed by the University of California at Berkeley. "BSD" is usually
preceded by the version number of the distribution, e.g., "4.3 BSD" is
version 4.3 of the Berkeley UNIX distribution. Many Internet hosts run
BSD software, and it is the ancestor of many commercial UNIX implementations.
Source: [NNSC].
BT (British Telecom). British
PTT.
BTNet
British Telecom Network Not to be confused with IBDNS, which
is also operated by BT.
btw An abbreviation for "by
the way".
Buffer A storage device.
Commonly used to compensate for differences in data rates or event timing
when transmitting from one device to another. Also used to remove jitter.
Bus A transmission path or
channel. A bus is typically an electrical connection with one or more conductors,
where all attached devices receive all transmission at the same time.
bus and tag channel The
original IBM channel developed in the 1960s incorporating copper multiwire
technology. Capable of operating at 4.5 Mbps with a distance limitation
of 125 meters. See also parallel
channel.
bus topology Linear
LAN architecture in which transmissions from network stations propagate
the length of the medium and are received by all other stations.
bypass mode Operating
mode on FDDI and Token
ring networks where an interface has deinserted from the ring.
Byte A group of bits as
needed to represent a single character in a given computer installation.
In today's computers, one expects 8 bits to be used for a single character
(8bit bytes); the unambigous way to name 8 bits is "octet".
byte-oriented protocol Class
of data-link communications protocols that use a specific character from
the user character set to delimit frames. These protocols ave largely been
replaced by bit-orienetd protocols.
byte reversal The process
of storing numeric data with the least-significant byte first. Used for
integers and addresses on devices with Intel microprocessors.