tems to grow. ASCII (American Standard Code for Information Interchange) The main 7-bit code personal computers use to translate bits into meaningful language. Most computers now use extended ASCII, which supports 8-bit codes. Each group of 8 bits represents a character. Computers can "read" one another's binary bits when these bits are arranged in a standard, uniform "language." ASCII is the most commonly used computer code. ATM (Asynchronous Transfer Mode) A high-speed switching technique that uses fixed-size cells to transmit voice, data, and video. A cell is analogous to envelopes that each carry the same number of bits. Used mainly in older networks. backbone A segment of a network used to connect smaller segments of networks together. Backbones carry high concentrations of traffic between on and off ramps to networks. backhaul A term used mostly to describe the links between antennas at base stations and mobile central offices, and services in the cellular networks core. Traffic and signaling information is backhauled from where it enters the network to the mobile core, and vice versa. band refarming The reuse of portions of spectrum for more advanced mobile protocols. Many countries are refarming spectrum originally used only for older second- www.TechnicalPDF.com generation services to newer fourth-generation technologies. bandwidth The measure of the capacity of a communications channel. Analog telephone lines measure capacity in hertz (Hz), the difference in the highest and lowest frequency of the channel. Digital channels measure bandwidth in bits per second (bps). BGP (Border Gateway Protocol) A routing protocol with more than 90,000 addresses. Used by carriers to route packets on the Internet. BGP enables routers to determine the best routes to various destinations. bill and keep A carrier-to-carrier billing method that eliminates the requirement for carriers to bill each other access fees. It is used by billing companies only to bill carriers that carry less traffic than carriers with whom they exch