backup domain controller (BDC)
In a Windows NT Server domain, a computer running Windows NT Server that receives a copy of the domain's directory database, which contains all account and security policy information for the domain. The copy is synchronized periodically and automatically with the master copy on the primary domain controller (PDC). BDCs also authenticate user logons and can be promoted to function as PDCs as needed. Multiple BDCs can exist on a domain. See also domain controller; primary domain controller.
bandwidth
In communications, the difference between the highest and lowest frequencies in a given range. For example, a telephone line accommodates a bandwidth of 3000 Hertz (Hz), the difference between the lowest (300 Hz) and highest (3300 Hz) frequencies it can carry. In computer networks, greater bandwidth indicates faster data-transfer capability and is expressed in bits per second (bps).
Basic (clear-text) authentication
A method of authentication that encodes user name and password data transmissions. Basic authentication is called "clear text" because the base-64 encoding can be decoded by anyone with a freely available decoding utility. Note that encoding is not the same as encryption. See also challenge/response authentication; encryption.
BDC
See backup domain controller.
bits per second (bps)
The measure of speed at which data is transferred over a network.
blue screen
The screen displayed when Windows NT encounters a serious error.
bootstrap protocol (BOOTP)
A TCP/IP network protocol used to configure network computers. Defined by RFC 951 and RFC 1542. DHCP provides a superset of the functions provided by BOOTP. DHCP and BOOTP interoperation is defined by RFC 1534. See also Dynamic Host Configuration Protocol.
bps
See bits per second.
browser
See Web browser.
BSD UNIX
A version of UNIX developed by Berkeley Software Design Incorporated.
bulk data encryption
The encryption of all data sent over a network.