|
backbone
A backbone is the portion of a network that carries the most significant traffic. It is also the part of the network that connects many smaller networks to form a larger network.
bandwidth
Bandwidth is a measure of the information-carrying capacity of a channel. In analog networks, bandwidth is the difference between the highest and lowest frequencies that can be transmitted across a communication link. Analog networks measure bandwidth in cycles per second (Hz). Digital networks measure bandwidth in Kbps, Mbps, and Gbps.
baseband
Baseband is a form of digital modulation in which one signal takes up the entire available bandwidth of the communication channel.
beta test
A beta test is the final stage of software testing in which volunteers use a new application or OS under real-world conditions.
binary
Binary refers to the base 2 numbering system used by computers to represent information. Binary numbers consist of only two values: 1 and 0. In a binary number, each position is two times greater than the position to its right.
bit
A bit, also referred to as a binary digit, is a single value that makes up a binary number. A bit can be either 1 or 0. See binary.
bits per second (bps)
The number of binary bits transmitted per second is measured in bps. For example, common modem speeds are 28,800 bps and 56,000 bps. Another way of writing 28,800 bps is 28.8 Kbps, because "kilo" means 1,000.
Bluetooth
"Bluetooth" is an open standard (IEEE 802.15.1, under development) for short-distance wireless personal area networking between handheld computers, peripheral devices, and other smart electronic appliances. It uses frequency hopping spread spectrum radio transmission in the 2.4-GHz range.
BNC connector
BNC connectors are small devices used to connect computers to a thin coaxial cable bus (10Base2) or terminate the ends of a bus. There are several different types of BNC connectors. A BNC barrel connector joins two Thinnet cables. A BNC terminator is used to terminate the end of a cable. It acts as a resistive load that absorbs the signal that reaches one end of the bus. (Two terminators are needed on each bus.) BNC adapters connect different types of cable, such as Thinnet to Thicknet.
bridge
A bridge is a device that operates at the Data Link Layer of the OSI model. It can connect several LANs or LAN segments of the same media access type, such as two Token Ring segments, or different LANs, such as Ethernet and Token Ring.
broadband
Broadband is a communication medium with enough bandwidth to carry multiple signals simultaneously. A broadband analog system assigns each signal to a different band of frequencies. A broadband digital system uses multiplexing to carry multiple signals.
broadcast domain
A broadcast domain is the area of a network that will receive broadcast packets. Routers and Layer 3 switches create network segments that are separate broadcast domains, because they do not forward broadcast packets from one segment to another.
broadcast frame
A broadcast frame is a frame addressed to all nodes on a network. The frame address is a special number that tells all nodes that receive the frame to process it.
broadcast storm
Due to differences between nodes and bridges in different parts of a network, a broadcast frame can sometimes be misinterpreted. This leads to another broadcast frame by the bridge that misinterpreted it. The second broadcast frame is again misinterpreted, and so on. The result is a "storm" of broadcast frames that can severely degrade network performance. Sometimes storms can persist and eventually bring down an entire network.
bus
An external bus connects a computer to its peripheral devices. An I/O bus connects the central processor of a PC with the video controller, disk controller, hard drives, memory, and other I/O devices. See serial bus and parallel bus.
byte
One byte is equal to eight bits. See bit.
|