This document was retrieved from anonymous FTP site yuma.acns.colostate.edu at Colorado State University (June 29, 1992) Appendix A. Glossary of Networking Terms When dealing with computer networks, or the people that care for them, all sorts of strange terms are used. To help you make sense of this "alphabet soup," we have compiled a condensed glossary of the more common networking terms, many adapted from Douglas Comer's book, Internetworking with TCP/IP, and customized for networking here at Colorado State University. UPPER-CASE words in the text are defined elsewhere in the glossary. ADDRESS: Network addresses are usually of two types: (1) the physical or hardware address of a network interface card; for ETHERNET this 48-bit address might be 0260.8C00.7666. The hardware address is used to forward PACKETS within a physical network. Fortunately, network users do not have to be concerned about hardware addresses since they are automatically handled by the networking software. (2) The logical or INTERNET address is used to facilitate moving data between physical networks. The 32-bit INTERNET address is made up of a network number, a subnetwork number, and a host number. Each host computer on the INTERNET, has a unique address. All INTERNET addresses at Colorado State have a network number of 129.82, a subnet number in the range of 1-254, and a host number in the range of 1-254. All INTERNET hosts have a numeric address and an English-style name. For example, the INTERNET address for UCC's CYBER 840 is 129.82.103.96; its INTERNET name is csugreen.UCC.ColoState.EDU. ADDRESS RESOLUTION: Conversion of an INTERNET ADDRESS to the corresponding physical address. On ETHERNET, resolution requires broadcasting on the local area network. ARPA (Advanced Projects Research Agency): Former name of DARPA, the government agency that funded ARPANET and later the DARPA INTERNET. ARPANET: A pioneering long haul network funded by ARPA. It served as the basis for early networking research as well as a central backbone during the development of the INTERNET. The ARPANET consists of individual PACKET switching computers interconnected by leased lines. BANDWIDTH: The capacity of the transmission MEDIUM stated in bits per second or as a frequency. The BANDWIDTH of the optical fiber used in CSUNET is in the gigabit or billion bits per second range. ETHERNET coaxial cable is in the megabit or million bits per second range. CSUNET: Colorado State's campus backbone high-speed data network consisting of cisco Systems' GATEWAYS interconnecting departmental ETHERNETS (subnets) over optical fiber. CSUNET is connected to the INTERNET with a single 56,000 bit per second leased line between Colorado State and UC-Boulder. DOMAIN NAME SERVER: A computer that converts INTERNET names, such as csugreen.UCC.ColoState.EDU or handel.CS.ColoState.EDU, to their corresponding INTERNET numbers, such as 129.82.103.96 or 129.82.102.16. At Colorado State, a UCC computer provides this service for the campus any time mail is sent or received. It also permits users to use TELNET to csugreen.UCC.ColoState.EDU. ETHERNET: An IEEE 802.3 standard using baseband contention access over coaxial cable and twisted-pair wires. This 10-million bit per second networking scheme was originally developed by Xerox Corporation. ETHERNET is widely used on campus because it can network a wide variety of computers; it is not proprietary; and components are widely available from many commercial sources. FDDI (Fiber Distributed Data Interface): An emerging standard for network technology based on fiber optics that has been established by the American National Standards Institute (ANSI). FDDI specifies a 100-million bit per second data rate. The access control mechanism uses token ring technology. Colorado State's fiber optic cable plant is FDDI compliant thereby providing us with a tenfold upgrade path when CSUNET nears saturation. FTP (File Transfer Protocol): The INTERNET standard high-level PROTOCOL for transferring files from one computer to another. GATEWAY: A special-purpose dedicated computer that attaches to two or more networks and routes PACKETS from one network to the other. In particular, an INTERNET GATEWAY routes IP DATAGRAMS among the networks it connects. Gateways route PACKETS to other GATEWAYS until they can be delivered to the final destination directly across one physical network. HEADER: The portion of a PACKET, preceding the actual data, containing source and destination ADDRESSES and error-checking fields. INTERNET: A concatenation of many individual TCP/IP campus, state, regional, and national networks (such as CSUNET, SUPERNET, WESTNET, NSFNET, ARPANET) into one single logical network all sharing a common addressing scheme. INTEROPERATE: The ability of multi-vendor computers to work together using a common set of PROTOCOLS. At Colorado State we use TCP/IP PROTOCOLS to get PCs, Macs, Suns, DEC VAXs, CDC CYBERs, and other computers to work together allowing users on one host computer to log onto another host or to send mail and files between different hosts. IP DATAGRAM: The basic unit of information passed across the INTERNET. An IP DATAGRAM is to the INTERNET as a hardware PACKET is to a physical network. It contains a source and destination ADDRESS along with data. Large messages are broken down into a sequence of IP DATAGRAMS. LAN (Local Area Network): Any physical network technology that operates at high speed over short distances (up to a few thousand meters). At Colorado State a typical LAN is confined to a department or building although some LANs span several buildings. CSUNET is used to interconnect one LAN to another. MEDIUM: The material used to support the transmission of data. This can be copper wire, coaxial cable, optical fiber, or electromagnetic wave as in microwave. MULTIPLEX: The division of a single transmission MEDIUM into multiple logical channels supporting many apparently simultaneous sessions. CSUNET multiplexes dozens of TELNET, FTP and SMTP sessions. NODE: A computer that is attached to a network; also called a host. NSFNET: The national backbone network, funded by the National Science Foundation and operated by the Merit Corporation, used to interconnect regional networks such as WESTNET to one another. PACKET: The unit of data sent across a packet switching network. The term is used loosely. While some INTERNET literature uses it to refer specifically to data sent across a physical network, other literature views the INTERNET as a packet switching network and describes IP DATAGRAMS as packets. PACX: A device that enables many terminal users to compete for a limited number of ports on various host computers such as the CYBER 840, the administrative IBM, and the computer that supports Morgan Library's on-line card catalog. By using the cisco Systems Terminal Server, PACX users gain access to CSUNET, and CSUNET users gain access to non-networked hosts such as the administrative IBM computer. PROTOCOLS: A formal description of message formats and the rules two computers must follow to exchange those messages. Protocols can describe low-level details of machine-to-machine interfaces (e.g., the order in which bits and bytes are sent across a wire) or high-level exchanges between allocation programs (e.g., the way in which two programs transfer a file across the INTERNET). SMTP (Simple Mail Transfer Protocol): The INTERNET standard PROTOCOL for transferring electronic mail messages from one computer to another. SMTP specifies how two mail systems interact and the format of control messages they exchange to transfer mail. SERVER: A computer that shares its resources, such as printers and files, with other computers on the network. An example of this is a Network Files System Server which shares its disk space with a WORKSTATION that does not have a disk drive of its own. SUPERNET: The State of Colorado TCP/IP-based network, funded by Colorado Advanced Research Institute, used initially to connect campus networks at Colorado School of Mines, Colorado State, UC-Boulder, UC-Denver, UC-Colorado Springs, and Denver University to the INTERNET. SUPERNET is continually growing as other educational, governmental, and commercial organizations connect their networks to it. TCP/IP (Transmission Control Protocol/INTERNET Protocol): A set of PROTOCOLS, resulting from ARPA efforts, used by the INTERNET to support services such as remote login (TELNET), file transfer (FTP) and mail (SMTP). CSUNET uses TCP/IP. TELNET: The INTERNET standard PROTOCOL for remote terminal connection service. TELNET allows a user at one site to interact with a remote timesharing system at another site as if the user's terminal was connected directly to the remote computer. TERMINAL SERVER: A small, specialized, networked computer that connects many terminals to a LAN through one network connection. Any user on the network can then TELNET to various network hosts. A terminal server can also connect many networks users to its asynchronous ports. At Colorado State, the Computer Center supports a terminal server that enables CSUNET users to connect via our PACX to hosts, such as the administrative computer, which are not connected to the campus network. The terminal server supports an inbound modem pool allowing dial-up access to CSUNET. WORKSTATION: A networked personal computing device with more power than a standard IBM PC or Macintosh. Typically, a workstation has an operating system such as UNIX that is capable of running several tasks at the same time. It has several megabytes of memory and a large high-resolution display. Examples are the DEC VAXstation, used in the College of Engineering, and the IBM RT-PC. WESTNET: One of the National Science Foundation funded regional TCP/IP networks that covers the states of Arizona, Colorado, New Mexico, Utah, and Wyoming. SUPERNET is part of WESTNET. Up