Glossary

bandwidth: The difference, in Hertz (Hz), between the highest and lowest transmission frequencies. Used as a measure of the throughput or information-carrying capacity of a transmission channel.
bus: A linear network topology in which multiple hosts are connected by a single cable and transmissions on the cable are heard by all attached machines.
Ethernet: A packet-switched network technology invented by Xerox PARC that transmits data at 10 megabits/second on a bus topology using CSMA/CD access. With minor differences, Ethernet conforms to the IEEE 802.3 standard.
CSMA/CD: Carrier Sense Multiple Access with Collision Detection. A contention access method in which devices wishing to transmit first listen to the transmission medium. When no carrier signal is sensed, the machine transmits. If two machines transmit simultaneously, a collison is detected and each of the machines retransmits after a random period of time.
fiber optic: A medium that transmits data by pulses of light. Characterized by high bandwidth, small physical volume and immunity from electromagnetic interference and radiation. More expensive than other media, but capable of higher data transmission rates.
firewall: A point of interconnection between two networks that filters or blocks the transmission of certain classes of traffic. May also provide relay services to compensate for the restricted access. Typically positioned between an organization and the outside world so as to prevent unwanted access to and/or from other networks.
GIF: Graphics Interchange Format
Internet address: A 32-bit address assigned to hosts using TCP/IP. Consists of four octets separated by periods and specifies the network, subnet (optional) and host. Also called an IP address .
IP address: A 32-bit address assigned to hosts using TCP/IP. Consists of four octets separated by periods and specifies the network, subnet (optional) and host. Also called an Internet address .
JPEG: JPEG (pronounce "jay-peg") is a standardized image compression mechanism. JPEG stands for Joint Photographic Experts Group, the original name of the committee that wrote the standard. JPEG, designed for compressing full-color or grayscale images of real-world scenes, works well on photgraphs, naturalistic artwork, etc. and not so well on lettering and simple cartoons. One can adjust the compression parameters and trade off file size against image quality. For more details on the JPEG compression m echanisn, see the FAQ on JPEG at http://www.cis.ohio-state.edu/hypertext/faq/usenet/jpeg-faq/faq.html
MPEG: MPEG stands for "Moving Pictures Experts Group". MPEG is a group of people that meet under ISO (the International Standards Organization) to generate standards for digital video (sequences of images in time) and audio compression. In particular, it d efines a bit stream for compressed video and audio optimized to fit into a bandwidth (data rate) of 1.5 Mbits/s. This rate is special because it is the data rate of (uncompressed) audio CD's and DAT's. For more information on the MPEG compression standard see the MPEG FAQ