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Glossary : B

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collapse/expand B channel
  • Bearer channel. ISDN channel that carries data at the rate of 64 kbps. Also see D channel.

collapse/expand Backbone
  • A network that aggregates traffic from smaller networks and transports traffic between networks. Typically, backbone network has larger capacity or higher transmission speed to move a huge amount of data from networks to networks. Fiber optic is the transmission medium of choice for most backbone networks. While SONET/SDH or DWDM are used to light the fiber.

collapse/expand Bandwidth
  • Bandwidth is the width of a frequency band (channel) denoted in Hz (Hertz). Bandwidth is often confused with data rate (or capacity / transmission speed) in bps (bit per second) because bandwidth is directly proportional with data rate. The larger the bandwidth the higher the data rate.
    Bandwidth utilization or spectral efficiency in bps/Hz is often mentioned when comparing the quality of different wireline or wireless communication systems. It is the number of bits that can be communicated within a channel bandwidth at any given time period.
    The relation between channel capacity (C) and channel bandwidth (BW) is clearly illustrated in the famous Shannon's law :
    C = BW*log2(1+SNR)
    SNR or S/N is the ratio of signal to noise.

collapse/expand Baseband
  • Baseband signal is signal (information) that is carried over a single communication channel. For example, voice signal in a telephone line is carried over a single channel therefore voice signal is a baseband signal. Ethernet is also a baseband transmission technology where signal (data) is carried in one channel.
    Contrast with broadband.

collapse/expand Baud rate
  • Refers to modem communication speed. It indicates the rate at which changes occur in signal over a given period of time. It is only equal with bit rate, IF each transmitted signal corresponds with one bit data. A.k.a. signaling speed or modulation rate.

collapse/expand Beacon
  • Packet that is sent by a computer or a device at a regular interval to inform other computers or devices of its presence in a wireless network.

collapse/expand BER
  • Bit Error Ratio. The ratio of the number of bits that are received incorrectly to the total number of bits that are transmitted.

collapse/expand BGP
  • Border Gateway Protocol. An interdomain routing protocol that interconnects autonomous systems on the Internet. BGP was designed to replace EGP.

collapse/expand Binary
  • A numeral system with 2 as its base. It is represented by two digits, namely 1 (one) and 0 (zero). For example 2 in decimal system is represented by 10 (read: "one O", NOT "ten") in binary system. Conversely, 111 in binary equals 1x22+1x21+1x20 or 7 in decimal system. Each digit position is equivalent with 2 raised to the power of its order from the rightmost position. The count starts at zero.
    Also see hexadecimal.

collapse/expand bit
  • Bit is a shorthand of binary digit. It refers to one digit in binary system, either 1 (one) or 0 (zero). Bit is the smallest information unit in computer or digital system. It represents two opposite conditions, such as true and false or on and off. In computer circuits, bit is translated to two different voltage levels.
    Also see binary.

collapse/expand bluebugging
  • A type of attack to a Bluetooth device that enables the hacker to make phone calls, send and receive messages, read and write phonebook contacts, tap phone conversations, and connect to the Internet.

collapse/expand bluejacking
  • A practice of sending an unsolicited message via Bluetooth to a nearby device. Bluejacking is possible during pairing because the name of the initiating device is displayed on the target device as part of the handshake process. The user defined name field can be up to 248 characters, so it can be used to send message.

collapse/expand bluesnarfing
  • A type of attack on Bluetooth device that is aimed to read, modify, or copy some personal information such as address book and calendar. Bluesnarfing abuses the OBEX (object exchange) protocol that is supported by Bluetooth.

collapse/expand Bluetooth
  • A wireless technology, using radio as its physical medium, that operates in the ISM band, using 79 1-MHz-channels (or 23 channels in some countries) between 2.402 and 2.480 GHz. With data rate of 721 kbps and range between 10 - 100 meters, Bluetooth is used as a cable replacement technology to connect computer or mobile phone with peripherals for data and image transfer, synchronization, and voice application. Bluetooth is also used to create Wireless Personal Area Network (PAN).
    Unlike IrDA (infrared) which requires devices to be in LOS (line-of-sight), Bluetooth radiation is omnidirectional and can pass through non-metal solid barriers like wall. This means more freedom for portable or mobile device user to move around while maintaining the wireless connection. However, to establish a Bluetooth connection for the first time, two Bluetooth devices have to discover and pair with each other. It takes few seconds normally, but may be longer if more Bluetooth devices are present within their range.
    The latest version of Bluetooth, that is Bluetooth 2.0 with EDR (Enhanced Data Rate), supports data rate of up to 3 Mbps. But most Bluetooth transceivers (adapters) today are of Bluetooth 1.1.
    Also see FHSS, 802.15.1 and PAN.

collapse/expand Bluetooth device
  • Computer, peripheral, or any electronic device that has Bluetooth transceiver. Bluetooth device can transmit and receive signal using Bluetooth radio wave.

collapse/expand Bluetooth SIG
  • Bluetooth Special Interest Group. An industry association that develops and promotes Bluetooth standard. Founded in February 1998 by five founding members, i.e. Ericsson, Nokia, Intel, IBM, Toshiba. Now it has hundred members coming from diverse industries having interest in adding Bluetooth into their products.

collapse/expand BNC
  • Bayonet Neill-Concelman. BNC connector is a cylindrical connector about 1 centimeter wide that is used to terminate a coaxial cable.
    Also see coaxial cable.

collapse/expand BNEP
  • Bluetooth Network Encapsulation Protocol. A protocol that is used to exchange Ethernet packets between Bluetooth devices in a Personal Area Network (PAN). BNEP is part of PAN profile.
    Also see PAN.

collapse/expand BPON
  • Broadband PON. A PON (Passive Optical Network) specification that was defined by the FSAN (Full Service Access Network) group of service providers in 2001. As an improvement of APON, BPON has overlay wavelength (WDM) to carry RF video. BPON also uses ATM encapsulation to carry traffic. Currently BPON is the most widely deployed PON architecture.
    Also see PON.

collapse/expand bps
  • Bit per second. Refers to the number of bits that are transmitted in a period of one second. bps is data rate (transmission speed) unit.

collapse/expand BPSK
  • Binary PSK (Phase Shift Keying). A form of PSK where each bit is transmitted individually.
    Also see PSK and QPSK.

collapse/expand BRI
  • Basic Rate Interface. An ISDN circuit that contains two Bearer channels and one Delta channel (or often designated as 2B+D) and has data rate of 128 kbps if the D channel is only used for signaling and control.
    Also see ISDN, B channel, and D channel. Compare with PRI.

collapse/expand Bridge
  • A network component that divides a network into segments and connects networks that have different Layer 2 protocols if the higher layer protocol is the same or can be translated. Bridge works at Layer 2 of the OSI model, it forwards packets based on physical (MAC) address.
    In corporate networks, bridge is commonly used to segment departments so as to prevent intra-department traffic to travel to other departments.

collapse/expand Broadband
  • Broadband signal is signal (information) that is carried over multiple communication channels.
    In consumer term, broadband refers to high speed and always-on Internet connection such as using DSL or cable modem.
    Also see baseband.

collapse/expand Broadcast
  • The transmission of data (packet) from a transmitter (server) to all receivers (workstations).
    Compare with unicast and multicast.

collapse/expand Brouter
  • A network component that combines the functions of bridge and router.

collapse/expand Browser
  • A software program that interprets information written in mark up languages such as HTML, XML, XHTML, and WML into a format/style that can be viewed on the screen of a computer or other devices.
    You read this Web page on your favorite browser.

collapse/expand BSS
  • Basic Service Set. Refers to a wireless LAN access point or each client in a wireless LAN if the wireless LAN works in infrastructure mode.

collapse/expand BSSID
  • Basic Service Set ID. SSID of a wireless LAN access point in infrastructure mode.

collapse/expand Bus Topology
  • Bus Topology is a network topology where each node is connected to a single cable trunk. The term "bus" refers to the cable trunk. The trunk needs a terminator at each end to prevent signal reflection. 10Base2 and 10Base5 networks implement bus topology.
    In bus topology, signal (data packet) is broadcast to all nodes. Each node (computer) examines the packet as it travels along the bus. If the packet's destination address matches a computer address, the packet is processed by the computer, otherwise it continues its travel along the bus.
    Since the node in a bus topology is passive (only listens for signals), failure in one node doesn't affect the other nodes. But failure in the trunk will stop the network.
    See picture.

collapse/expand byte
  • A data unit that contains 8 (eight) bits. Sometimes, called an octet. An alphabet character (i.e. A, B, C, ...) is a one byte information.