Glossary Section "B" ( Definitions )
BABT British Approval Boards for Telecommunications
B8ZS stands for Binary 8 Zero Substitution. It is a technique that allows 64Kbps clear data per T-carrier channel. Because of the ones density requirement of a T-carrier system, a one must be inserted for every seven consecutive zeros. B8ZS circumvents this requirement by inserting two code violations on a physical link instead.
backbone The primary connectivity mechanism of a hierarchical distributed system. All systems which have connectivity to an intermediate system on the backbone are assured of connectivity to each other. This does not prevent systems from setting up private arrangements with each other to bypass the backbone for reasons of cost, performance, or security. See core gateway.
backhoe attenuation A line failure caused when someone digs up the line in error.
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. See bps.
baseband bridge A device connecting local networks at the OSI data link layer that filters and forwards frames according to MAC addresses using transmission of a digital or analog signals at its original frequency as an un-modulated signal.
Baud Rate The number of signal transitions per period.
BECN Backward Explicit Congestion Notification is a bit set in a Frame Relay network to notify a DTE device that congestion is occurring and that the sending device should be notified to initiate congestion procedures.
BCP The newest sub-series 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.
BCM Bit Compression Mux
bearer service As defined by CCITT standards, a type of telecommunication service that provides the capability for the transmission of information between user-to-network interfaces. Bearer services defined for ISDN are circuit mode and packet mode.
BER Basic Encoding Rules. Rules for encoding data units described in ASN.l. Sometimes incorrectly lumped under the term ASN.1, which properly refers only to the abstract syntax description language, not the encoding technique.
BGP Border Gateway Protocol. An inter-autonomous system routing protocol. This allows groups of routers to share routing information and is frequently used by ISPs. The "next generation" EGP. See EGP.
BIND Berkeley Internet Name Domain. Implementation of a DNS server originally 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. The current maintainer of BIND is Paul Vixie.
Bit Interleaving/Multiplexing A process used in time division multiplexing where individual bits from different lower speed channel sources are combined into one continuous higher speed bit stream, one bit from one channel at a time.
BITNET Because It's Time NETwork. An academic computer network based originally on IBM mainframe systems interconnected via leased 9600 bps lines. BITNET merged with CSNET, The Computer+Science Network (another academic computer network) to form CREN: The Corporation for Research and Educational Networking. See CSNET.
BLI Busy Line Interrupt
BLV Busy Line Verification
BLVI Busy Line Verification Interrupt
BOD Bandwidth On Demand
BONDING Bandwidth On Demand Interoperability Group
BPV Bi-Polar Violation. The occurrence of successive ones of the same polarity. Normally a transmission line induced error. B8ZS transmits intentional BVPs in certain patterns to meet the one's density requirements of a T1 circuit.
bridge A device that connects two or more physical networks and forwards packets between them. Bridges can usually be made to filter packets, that is, to Forward only certain traffic. Related devices are repeaters which simply forward electrical signals from one cable to another, and full-fledged routers which make routing decisions based on several criteria. In OSI terminology, a bridge operates at the Data Link Layer. See repeater, router, intermediate system.
broadband Characteristic of any network that multiplexes multiple, independent network carriers onto a single cable. This is usually done using frequency division multiplexing. Broadband technology allows several networks to coexist on one single cable; traffic from one network does not interfere with traffic from another since the "conversations" happen on different frequencies in the "ether," rather like the commercial radio system. See base-band.
Broadcast Storm A condition that can occur on broadcast type networks such as Ethernet. This can happen for a number of reasons ranging from hardware malfunction to configuration errors and bandwidth saturation.
BSC Bisychronous Communications
BSRF Basic System Reference Frequency - stratum 1 clock source
BSD Berkeley Software Distribution. Term used when describing different versions of the Berkeley UNIX software, as in "4.3BSD UNlX."
BTW By The Way. One of many short-hand phrases used in chat sessions and e-mail conversations. See IMHO.
Buffer A storage device, commonly used to compensate for differences in data rates or event timing when transmitting from one device to another.
Bus A transmission path or channel, typically an electrical connection with one or more conductors.
Byte A group of bits, generally 8.