Back Bone- The major transmission path for a packet data network (PDN). It is the high-density connectivity portion of any communications network.
Bandwidth- The difference between the limiting frequencies of a continuous frequency band.
BNC- A bayonet-locking connector for miniature coax; BNC is an acronym for Bayonet-Neill-Concelman. It is used for RG-58 or RG-59 sizes of coax.
Bridge- Devices that connect LANs at the data-link layer of the Open Systems Interconnection (OSI) model. Major function is to forward and filter packets, depending upon their destination addresses. A device that connects different LANs so a node on one LAN can communicate with a node on another LAN.
Broadcast- 1. Transmission of a message intended for a general reception rather than for a specific station. 2. In LAN technology, a transmission method carrier sense multiple access/collision detect (CSMA/CD) used in bus topology networks that sends all messages to all stations even though the messages are addressed to specific locations.
Brouter- A device with the combined capabilities of a bridge with data handling functions of a router. Typically, a brouter will route one protocol, such as internet protocol (IP), and a bridge all other traffic. Generally it is used when there is a mix of homogenous LAN segments with two very different segments.
Bus- One or more conductors or optical fibers that serve as a common connection for a related group of devices.
Cable Conduit- A pipe or tube used to protect one or more cables going from one place to another.
Cable Tray- An open-top channel used to support and route cables.
Circuit Switched- The connection is similar to voice lines. The communication path is fixed for the duration of the connection. The sending computer would initiate a call via modem to the receiving computer, transfer the data, and then terminate the link. This is a dedicated circuit for the entire session.
Client-Server- In a communications network, the client is the requesting machine and the server is the supplying machine.
Closed System- A network which does not interoperate with networks of a different vendor. It is a vendor proprietary system.
Coax- "CO-AXial," a type of cable with a conductive coating (foil or braid) surrounding an insulated center conductor. It is used to carry high-frequency signals.
Collapsed Backbone- The back plane in a hub which contains the backbone bus for the input/output (I/O) modules of the hub.
Communications Closet- An enclosure where communication interconnect path panels and networking connection equipment are located.
Communicating Devices- A device used in the electronic connection of a network.
Communications Server- A computer that controls one or more modems or terminals, provides protocol conversion, or acts as a gateway to other networks.
Concatenate- The connection or linking of a series.
Connectionless - A service in which data is presented, complete with a destination address, and the network delivers it on a best effort basis, independent of other data being exchanged between the same pair of LAN users.
Connection-Oriented- A service in which a connection-setup procedure must be implemented before data can be exchanged between two LAN users. This often includes ensuring that data packets will be delivered in order, without loss or duplication. If a minimum level of service cannot be maintained, the connection is automatically terminated.
Database Server- The database operations are performed on a centralized server. Where databases are stored on the LAN.
Dc Resistance- The resistance of a circuit with no alternating current (ac) components. Resistance to an unchanging current, no reactance.
De Facto- The exercising of power as if legally constituted. Standardized by way of widespread use.
Dielectric- Any substance in which an electric field may be maintained with zero of near-zero power dissipation; a nonconductive material.
Directory- Directories represent the path established to store and retrieve the actual files off the storage media.
Distributed Processing- An arrangement that allows separate computers to share work on the same application program. In a distributed processing system, a program executes tasks on many processors spread around the network.
E -Mail, Electronic Mail- Electronic Mail refers to messages sent between subscribers electronically via a public or private data communications system. LAN users can send mail to a single recipient or broadcast it to multiple users on the system.
EIA/TIA- Electronics Industries Association/ Telecommunications Industry Association. USA trade organizations that issue standards and contribute to the American National Standards Institute.
Engineering Drawing- The floor plans of buildings drawn to scale and showing details of internal structures, such as walls and doorways.
Ethernet- A de facto standard, developed first by Xerox and then sponsored by Xerox, Intel, and DEC. An Ethernet LAN can use twisted-pair (TP), fiber optic, or coaxial cables. Ethernet is used to designate Institute of Electrical and Electronics Engineers (IEEE) 802.3 compliant networks.
Expansion Bus- The portion of the computer design for adding capabilities, such as printer controller, disk controller, or network interface card.
Fax Server- A dedicated communication personal computer (PC) for providing the network with the ability to share incoming and outgoing facsimile transmissions.
Fiber Optics- A fiber optic cable consists of a strand of fiber material, usually glass, inside of a protective jacket. Signals are transmitted in the form of light pauses.
File Server- The file server is the central node that provides network services found in the network operating system. The server which provides bulk storage of user files.
Gateway- Often the gateway changes the format of the messages to conform to the applications program at the receiving end. This allows networks with totally incompatible protocols to communicate.
Hardware- Equipment (as opposed to a computer software) such as mechanical, electrical, magnetic or electronic devices.
High-Speed Router- A device that sorts packets of information on a network and forwards to the correct network. Routers can translate between a wide variety of cable and signaling schemes.
Hub- The hardware equipment used at the center of a star topology network or cabling system. The hub can be active or passive. An active hub serves as a repeater to other active LANs and will amplify as well as recondition the signal. A passive hub provides no amplification and contains no intelligence like the active hub.
Hybrid Cable- A cable containing more than one type of medium, typically, unshielded twisted-pair (UTP) and fiber optic.
Index of Refraction- The ratio of the velocity of light in free space to the velocity of light in a given material.
Information Drop- A wall or floor plate where users connect telephone or network equipment to the building's communications infrastructure.
Intelligent Hub- The hardware equipment used at the center of a star topology network or cabling system with inherent remote management capabilities.
Interconnection- The linking together of interoperable systems.
Internetwork- A set of interconnected, logically independent networks. The constituent networks are usually administrated separately and may be composed of different transmission media.
interoperable- The ability of software and hardware on multiple machines from multiple vendors to communicate meaningfully.
intranetwork- Within the boundaries of a local network.
Jabber Packet- An over length Ethernet packet (greater than 1518 bytes long).
Kevlar- A fibrous material of very high strength.
Local Bridge- The local bridge directly connects two LAN cable segments. Bridges use tables to decide whether to pass or hold data messages (similar to routers).
Login- The procedure which allows the user access to a server on a LAN.
Logoff - This procedure terminates connection with a particular server.
Mainframe Computer- A large-scale computer, normally supplied with peripherals and software from a single vendor, commonly a closed architecture. Also called host or central processing unit (CPU) or mainframe computer.
Media- This refers to the method of transmission, such as infrared (IR), microwave, or the type of cable (coaxial, UTP, or fiber optic).
Media Access Control (MAC)- Bottom sublayer of OSI data-link layer (layer2). It represents the physical station address or the hardware address of the network board. A MAC address is unique for every station. Bridges rely on MAC addresses for operation.
Message Switching- A routing technique using a message store-and-forward system. No dedicated path is established. Rather, each message contains a destination address and is passed from source to destination through intermediate nodes. At each node, the entire message is received, stored briefly, and then passed on to the destination node.
Micron - One- millionth of a meter.
Microprocessor- A computer-on-a-chip or the CPU. This component determines and controls the computer's processing characteristics, power, and types of software programs it can process.
Minicomputer- A small-scale of medium-scale computer, usually operated with interactive dumb terminals and often having an open architecture. Also called mini for short.
Modal Dispersion- Dispersion resulting from the different transit lengths of different propagating modes in a multimode optical fiber.
Modem- A contraction of the terms modulator and demodulator. It modulates computer signals from digital-to-analog, analog-to-digital, and digital- to-digital form, thus enabling data to travel over a telephone system.
Mouse- A hand-held computer input device that generates the coordinates of a position indicator which appears on a computer monitor, and operates by being moved.
M-port- A single-attach connection at a fiber distributed data interface (FDDI) concentrator.
Multimode Fiber- A fiber optic cable wide enough to allow light to reflect internally at several different angles. Multimode can use a mix of light frequencies.
Multiport Bridge- A bridging device that connects more than two adjacent networks. Multiport bridges with a high internal bandwidth can simultaneously support full-speed communication on all ports.
Network Operating System- A program that manages resources across an entire LAN, such as remote file systems that are accessible by the workstations, the loading and execution of shared application programs, and I/O to shared network devices.
Node - Any device connected to a network, such as a workstation or file server.
Open System- Interoperability solution in which a vendor makes products compliant with universally accepted standards. The development of the OSI model is a step towards standardization.
Operating System- Software used to control the basic operation of a computer. It allows user to access files, run programs, use printers, etc..
Packet Switch Connection- This connection provides a shared physical connection. A message is submitted to the network for delivery. This message is subdivided into specific size packets for transmission. This type of connection is not time sensitive. A virtual circuit which defines the logical connection is created.
Peer-to-Peer- A LAN that allows all LAN users to access data on other workstations.
Peripheral Device - Any equipment, distinct from the central processing unit, used to provide additional capabilities or process data for entry into or extraction from a computer.
Peripherals- See peripheral device.
Plenum- An open space, used for office air circulation, where cable can be run. Due to fire and noxious gas potentials, special safety cable must be used.
Plenum Rated Cable- A cable that has a special coating or sheath which minimizes the release of noxious gases when exposed to flames or heat.
Point-to-Point Link- Transmission of data between a single sender and receiver. A point-to point is a circuit connecting two station to each other only, with no intermediary node.
Print Server- The print sever software accepts jobs from application programs running on client stations. stores them on a hard disk, and sends them to a printer when the job's turn occurs in the queue. Typically, the print server is in the file server, however, it may be on any PC on the LAN.
Protocol- In communications, a set of rules and regulations that govern transmitting and receiving of data. The means used to control the orderly exchange of information between stations on a data-link or on a data communications network system. Also called line discipline.
Random Access Memory- RAM, the working memory of the computer in which application programs and data can be stores and used by the CPU.
Read Only Memory- ROM, an integrated circuit used for storing frequently used computer instructions and data. ROM is permanent memory because data is not erased when the power is turned off.
Relay Slack- A structure with standard mounting rails of 19.5 inches wide. It is used to mount electronic equipment.
Remote Access- The connection between a computer or terminal to any network service, over either a LAN, dial-up modem, or other communication technique.
Remote Bridge- Remote bridges operate in pairs, connecting the LAN cable segments using an intermediary inter-LAN link such as a leased telephone line.
Repeater- A device used to extend transmission ranges/distances by restoring signals to their original size or shape. Repeaters function at the physical layer of the OSI mode.
RG-58 A/U- Coaxial cable assembly used as "Ethernet" thinnet 50 ohm cable.
Ring- A network in which every node has exactly two branches connected to it. The nodes are connected in series.
RJ-45- A modular connector with eight contacts, typically used in network connections of UTP cabling.
Router- Devices that function at the network layer of the OSI model and are protocol specific. Routers direct packets generated between networks, thereby reducing network traffic.
Routing Table - Routing tables are used to determine the best path to send packets. Routers examine the source and destination addresses in the packet to determine where the packet came from and where it needs to be delivered. Cost and distance are also used in routing determination.
RS-232-C/D- A physical interface protocol (EIA RS-232-C/D), the mechanical interface is the 25-pin ISO 2110 connector. It is used for the interface between data terminal equipment and data communication equipment.
RS-449- A physical interface protocol, EIA RS-449 was developed to attain improved performance over EIA RS-232-C. It enables longer cable distance, higher maximum data rates, and additional interface functions, for example, maintenance loopback testing. The interface was designed to be interoperable with RS-232 equipment. It uses a general purpose 37-pin connector (ISO 4902) for the basic interface and a separate 9-pin connector if a "secondary channel" operation is in use.
Server - A high-speed computer in a LAN used to store programs or data files shared by the LAN users on the network or perform network management of the LAN. There are different types of servers (such as file, database, print, fax, and communications), each performing a specific activity for the LAN.
Single-Mode Fiber- A small core diameter fiber which allows a single mode of light; light only travels along the axis of the finer. It can be used over greater distances than MultiMate fiber.
Software- A computer program or set of stored instructions and procedures held in some storage medium, such as read/write memory (RAM) that can be recalled or loaded in the computer for execution.
Spread Spectrum- Techniques that utilize signal frequency hopping at a rapid rate or that spread a transmitted signal across a range (band) of carrier frequencies.
Star- A radial (starlike) configuration of communication-network nodes such that there is a direct path between each node and a central node that serves as a central distribution node.
Star Coupler - A fiber optic coupler in which power at any input port is distributed to all output ports.
System Memory - The part of a computer where programs and information are stores while they are being used.
T1- T-carrier designation for a channel rate of 1.544 megabits per second (Mbps).
T3- T-carrier designation for a channel rate of 44.736 megabits per second (Mbps).
Tap- In cable-based LANs, a connection to the main transmission medium.
10Base2- A network conforming to the IEEE 802.3 local area network standard. The network is capable of carrying information at rates up to 10 Mbps over distances up to 185 meters (approximately 1600 feet) using RG-8 coaxial cable.
10BaseF- The standard defined for Ethernet communication over fiber optic cable.
10BaseT- A network conforming to the IEEE 802.3 local area network standard. The network is capable of carrying information at rates up to 10 Mbps over distances of 100 meters (approximately 325 feet) using twisted-pair cable.
Terminals- Any device capable of sending or receiving data over a data communications channel.
Terminate and TSR- is a unique application program that will stay in the computer's memory even Stay Resident though it is not currently the program being used. It is also called memory resident. Many TSR programs can be instantly entered from another program by the use of a hot key.
Thicknet- A type of Coaxial cable used for a 10Base5 network. See 10Base 5.
Thinnet- A type of Coaxial cable used for a 10Base2 network. See 10Base 2.
Timesharing- A method of computer operation that allows several interactive terminals to use a computer and its facilities; although the terminals are actually served in sequence, the high-speed of the computer makes it appear as if all terminals were being served simultaneously.
Token- That part of a packet used for network access on Token Ring LANs; the station that "owns" the token is the station that controls the transmission medium.
Token-Passing- An access method in which a special message (token) circulates among the network nodes, giving a node permission to transmit.
Token-Ring - The token-ring is described as a ring topology because the data is passed from station to station until it returns to the starting point. The token-ring usually has a physical star topology.
Topology- The architecture of a network, or the way circuits are connected to link the network nodes together.
Transceiver- A single device that combines the functions of a transmitter and a receiver.
Trustee - The user is assigned rights to perform operations, such as read, write, create, and erase files in a directory. The user entrusted with these rights is called a trustee and the actual rights assigned are called trustee assignments.
V .35- International Telecommunication Union- Telecommunication Standardization Section (ITU-TSS) (formerly International Consultative Committee for Telephone and Telegraph (CCITT)) standard for connection and signaling.
Watt- A unit of power, defined as the electrical work required to drive a current of 1 ampere across a potential of 1 volt.
Workstation- A computer used to run programs and provide communication to the LAN.
X .25- An ITU-TSS protocol for packet switching networks.
ac- Alternating current.
ACSE- Association Control Service Element
AMDR- Automatic message detail recording
AMMUS- Air Force Minicomputer Multi-User System
ANSI- American National Standards Institute
ASN.1- anstract syntax notation one
ATM - Asynchronous transfer mode
AU- Attachment unit interface
AWG - American Wire Gauge
AWSCEM- Army Wide Small Computer Equipment Maintenance
BDF- Building distribution frame
BER- Bit error rate
BNC- Bayonet connector
BOM- Bill of materials
BPA -Blanket Purchase Agreement
bps- Bits per second
BRI- Basic rate interface
CAPR- Information capability request
CCL- Certified Components List
CDDI- Copper distributed data interface
CD ROM- Compact disk read-only memory
CLNS- Connectionless-Mode Network Service
CONS- Connection-Mode Network Service
CNLP- Connectionless network layer protocol
CPU- Central processing unit
CSMA/CD- Carrier Sense Multiple Access/Collision Detection
CSU- Channel service unit
CUITN- Common Users Installation Transport Network
DAC- Discretionary access control
DARPA- Defense Advanced Research Projects Agency
DCE- Data communications equipment
DCID- Director Central Intelligence Directive
DDS- Digital data service
DEC- Digital Equipment Corporation
DIAM- Defense Intelligence Agency Manual
DISN- Defense Information Systems network
DoD- Department of Defense
DOIM- Director of Information Management
DOS- Disk operating System
DS1- Digital signal 1
DSN- Defense Switched Network
DSU- Digital service unit
DTE- Data terminal equipment
ECMA - European Computer Manufacturer's Association
EIA- Electronics Industries Association
EIP- Engineering installation plan
EISA- Extended industry-standard architecture
EMI- Electromagnetic interference
ESD- Electrostatic discharge
FCC- Federal Communication Commission
FDDI- Fiber distributed data interface
FIPS- Federal Information Processing Standard
FO- Fiber optics
FOIRL- Fiber optic Inter-Repeater Link
FTAM- File Transfer, Access, and Management
Gbps- Gigabits per second
GHz - Gigahertz
GNMP- Government Network Management Profile
GOSIP- Government open Systems Interconnection Profile
GUI - Graphical user interface
HDLC- High-Level Data-Link Control
HP- Hewlett Packard
HVAC- Heating, ventilation and Air Conditioning
IA - Implementation Agreement
IBM- International Business Machines Corporation
IDF- Intermediate distribution frame
IEC- International Electrotechnical Commission
IEEE- Institute of Electrical and Electronics engineers
IITS - Installation Information Transfer System
INIC- Intelligent network interface card
IP- Internetwork Protocol
IPX- Internetwork protocol exchange
IRQ- Interrupt request
ISDN- Integrated Services Digital Network
ISM- Industrial, scientific, and medical
ISO- International Standards Organization
ITU-TSS- International Telecommunication Union- Telecommunication Standardization Sector
kbps- Kilobits per second
khz km- Kilohertz kilometer
LAN- Local Area Network
LED- Light Emitting Diode
LLC- Logical link control
MAC- Mandatory access control
MAU- Medium attachment unit
Mbps- Megabits per second
MHS- Message handling system
MOTIS- Message-Oriented Text Interchange System
MS-DOS- Microsoft disk operating system
MTBF- Mean time between failures
NCC- National Control Center
NACSIM- National Communications Security Information Memorandum
NCSC- National Computer Security Center
NDIS- Network Driver Interface Specification
NEC- National Electric Code
NetBIOS- Network Basic Input/Output System
NFPA- National Fire Protection Agency
NIC- network interface card
NIST- National Institute of Standards and Technology
NMS- Network management system
NOS- Network operating system
NRZ- Non-return to zero
NSA- National Security Agency
OC- Optical carrier
ODI- Open-Data-Link Interface
OIW- Open Systems Implementer's Workshop
OLS- Optical Loss Set
OS- Operating System
OSE- Open systems environment
OSI - Open Systems Interconnection
OTDR- Open Time Domain Reflectometer
PAD- Packet assembler/disassembler
P/AR- Peak-to-average Ratio
PC- Personal Computer
PDN - Packet data network
PDS- Premises distribution system
PHY- Physical layer protocol
PLP - Packet Level Protocol
PMD -Physical Medium Dependent
PRI - Primary Rate Interface
PVC - Polyvinyl Chloride
RAM- Random Access Memory
RFI- Radio Frequency Interference
RISC- Reduced instruction set computer
ROM- Read-only memory
ROSE- Remote Operations Service Element
SIDPERS- Standard Installation/Division Personnel System
SMB- Server Message Block
SMC- Small Multiuser Computer
SMF- Single Mode Fiber
SMDS- Switched multimegabit data service
SMT- Station Management
SNMP- Simple Network Management Protocol
SONET- Synchronous optical network
SSRC II- Standard Software Requirements Contract II
ST- Snap Twist
STP- Shielded twisted-pair
TCP- Transmission Control Protocol
telco - Telephone company
TIA- Telephone Industry Association
TMDE- test, measurement, and diagnostic equipment
TP - Twisted-pair
TP4- Transmission protocol-4
TPDDI- Twisted-pair distributed data interface
TSB- Technical Systems Bulletin EIA/TIA
TSR- Terminate and Stay Resident
UHF- Ultra high frequency
UL- Underwriter's Laboratories
USAISEC- U.S. Army Information Systems Engineering Command
UPS- Uninterruptible Power
UTP- Supply unshielded twisted-pair
WAN- Wide Area Network
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