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Network Glossary


10 Megabits per second; standard Ethernet operating speed. (Also called bandwidth.) Since 8 bits make up a byte this speed equates to 1.25 megabytes per second. 

100 Megabits per second; Fast Ethernet operating speed. (Also called bandwidth.) Since 8 bits make up a byte this speed equates to 12.5 megabytes per second. 

10BASE-T cable 
An Ethernet cable system using twisted-pair wiring with RJ-45 plugs (similar to phone plugs but with 8 contacts) at each end. Category 3 10BASE-T cable is used with 10Mbps Ethernet networks. 
The standard for the physical media of Fast Ethernet products. Products that conform to the 100BASE-TX standard run on cable that meets the specification known as Category 5. 

100BASE-T cable 
An Ethernet cable system using Category 5 twisted pair wiring with RJ-45 plugs at each end. Used with 100Mbps Fast Ethernet networks. 


activity light 
An LED that verifies that the hardware is working, communicating with the network and that data is being transmitted through the device. 

The network system used by Macintosh computers. AppleTalk is a set of network protocols that control network file access, data transmission and other functions. AppleTalk can be implemented on a variety of cable systems, including LocalTalk, Ethernet, and Token Ring. 

AppleTalk Phase 2 
AppleTalk Phase 2 protocols provide extensions to the Ethernet networking system that support multiple zones and more devices. 

AUI connector/port 
The Attachment Unit Interface (AUI) is a DB-15 connector that connects to a transceiver (usually a small box) on cable systems such as thick Ethernet, twisted-pair, or fiber-optic cable systems. Ethernet cards sometimes have these ports in addition to RJ45 and coax cable connectors. 

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Describes the rate at which a network can transfer data. Standard Ethernet operates at 10Mbps. Fast Ethernet operates at 100Mbps. 

BNC connector/port 
A high grade locking connector used with thin and thick Ethernet cabling. The BNC port connects to thin Ethernet cables using a BNC Y- or T-connector. 

Bridges are used to connect two or more networks together so that devices on the networks can communicate. Bridges only connect networks running the same protocol. 

A network transmission sent to all nodes on the network. 

bus topology 
A networking setup in which a single cable, such as thin Ethernet, is used to connect one computer to another like a daisy chain to carry data over a network. (See star topology.)

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cable segment 
A cable segment is a section of network cable separated by hubs, routers, and/or bridges to create a subnet. 

Connecting hubs together with cable. Sometimes requires a crossover cable or a special setting on the hub to change one port to a cascading function with the ability to connect to another hub instead of an NIC. 

Category 3 cabling 
A 10BASE-T unshielded twisted-pair cabling type commonly used in today's 10Mbps Ethernet networks. 

Category 5 cabling 
A higher grade of unshielded twisted-pair cabling required for networking applications such as 100Mbps Fast Ethernet. Most commonly pre-wired in buildings wired within the last five years. 
A computer connected to a shared resource server. 

A network computing system in which individual computers (clients), use a central computer (server) for such services as file storage, printing, and communications. (See peer-to-peer) 

coax cable 
Thin or thick coax cable used in Ethernet networking. This looks similar to cable TV coax but usually has BNC connectors on the ends. 

Two packets sent over the network simultaneously will collide and be rejected. Ethernet will automatically resend them at altered timing to ensure proper receipt. Many hubs include LEDs to indicate collisions. 

Central Processing Unit. The main processing component in a computer. On a network, also used to refer to one computer. 

crossover cable 
A cable in which the receive and transmit lines (input and output) are crossed. Crossover cables are needed to connect hubs together.

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data transmission speed 
The number of bits that are transmitted per second over a network cable. 

Direct Cable Connection. A simple networking setup under Windows 95/98, often using a cable between two computers' parallel ports. 

dedicated server 
A computer on a network that is assigned to function only as a resource server and cannot be used as a client. 

Networking equipment such as a hub, switch, bridge, router, etc. 

A software program that allows a computer to use and communicate with equipment or peripherals installed on the computer. For example, network interface cards (NICs) require drivers to allow the computer to communicate with the network through the NIC. 
Dial Up Networking. A way to connect to a network, including home networks, by dialing in over phone lines to a modem on a computer acting as a server.

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Networking standards originally developed in 1973 by Xerox and formalized in 1980 by DEC, Intel, and Xerox which transmits data at 10Mbps using a specified protocol. The most popular Local Area Network (LAN) technology in use today. 

Ethernet address 
Each Ethernet network node has its own unique Ethernet address that is obtained automatically when an Ethernet adapter is added to the computer. This number identifies the node as a unique communication item and enables direct communications to and from that particular computer. 

The AppleTalk network system used with an Ethernet network.

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Fast Ethernet 
An Ethernet networking system which transmits data at 100Mbps; theoretically 10 times fast than Ethernet. 

fiber-optic cable 
Fiber-optic cables transmit digital signals as light pulses. Fiber optic cable connections are made through an AUI port using an external transceiver. 

file server 
A dedicated network computer used by client computers to store and access software and work files. 

full duplex 
Network connection type that provides for network nodes sending and receiving data at the same time, thus doubling the theoretical "speed limit" of connections. For example, normal fast Ethernet, at 100Mbps, runs at half duplex. With switched connections, which allow full duplex, the transmission speed is 200Mbps.

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A gateway is node that translates between two otherwise incompatible networks or network segments. Gateways perform code and protocol conversion to facilitate traffic between data highways of differing architecture, for example Ethernet and Token Ring.

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half duplex 
The normal connection type of network interface cards on Ethernet setups. Data can only be received or transmitted at one time (not both). 

Components of a computer system including monitors, hard drives, CD-ROMs, printers, modems, etc. 

A term used when counting components and wiring segments in an Ethernet network to determine whether Ethernet compliance has been met. 

The ability to add and/or remove PC cards without restarting the computer to use the cards. 

Also referred to as a "repeater" or "concentrator", its primary function is to receive and send signals along the network between the nodes connected to it. For home users, hubs usually have 4-8 "ports" (or RJ-45 jacks) that connect cables coming from individual computers on the network.

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A "worldwide" network of information which can be accessed by a modem and communication software through an Internet Service Provider. 

internet sharing software 
Software used on one computer in a network setup that allows other computers on the network to share the internet dial up on the first computer. Also known as proxy software. 

A large multi-segment network or "internet." Two or more networks connected by routers and bridges. Networks in an internetwork share information and services. 

Similar to the "Internet", this is a local, internal network, usually set up within a single company or organization. 

Stands for Internet Protocol. TCP/IP protocol for packet forwarding. (see also TCP/IP). Protocols are the computer "languages" used to transfer data across networks. 

Stands for Internet Packet eXchange. This is a popular protocol in PC networks and is often used for playing games across a local network. 

Stand for Industry Standard Architecture, but is most commonly used as the name of one type of slot in PCs. Some network cards, internal modems, video cards and other peripherals plug into these ISA slots. Increasingly, ISA slots (and associated peripherals) are being replaced by PCI slots, which provide faster data transfer and easier setup in computers. 

Integrated Services Digital Network. Digital switching and carrying data, voice, computer transmissions, music and video at speeds exceeding that of traditional analog telephone lines. Although ISDN once looked to be a major replacement for regular phone lines, it has already been replaced by cable modems and xDSL phone service.

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The 10BASE-T standard sets limits on how long a node may transmit before it has to stop to allow other nodes an opportunity to transmit. Transmissions longer than the standard limit usually indicate adapter problems.

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One thousand bits of data. 240 kilobits per second means 240,000 bits of information are being transmitted over a network per second (240 Kbps). Recall that 8 bits comprise a byte.

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Local Area Network. A network that is in one location and that allows users to share resources such as file storage and print services. 

Small indicator lights on electronics and networking devices that provide indication of status and other information about the device. 

Apple Computer's communication hardware and cable system that connects computers and other devices such as printers or file servers in an AppleTalk network. LocalTalk connectors are built in to every Macintosh computer and Apple printer. 

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Stands for Media Access Controller. The MAC determines how a data packet is sent across the network, including the source and destination of the packet. 

Networking wiring such as 10BASE-T and 100BASE-T UTP cable, and coax cable. 

One million bits of data. (10 Megabits per second, or Mbps, means that 10 million bits of data are being transmitted over the network per second.) Don't confuse with megabyte, the usual measure of computer memory and storage space. Eight bits make up one byte. 

A communications product that sends computer transmission over a standard telephone line at pre-set speeds. 

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Another protocol for network data communications. Microsoft's LAN Manager and Windows NT protocols. Easy to set up, but not widely used for network game playing or internet sharing. 

The means by which computers and other networking devices are connected together so that print services, files, equipment, and software applications may be shared. 

network interface adapter 
Also called a network interface card, or NIC, it serves as the interface by sending and receiving data between the computer and the network cabling. Network interface adaptors may work either internally, such as a PCI, or ISA card, or more rarely, externally, such as a SCSI adapter which connects to a computer's SCSI port. 

Network Operating System 
NOS. A special application that allows computers and other devices on the network the ability to communicate and accept and receive information. Windows95, the Mac OS, and Windows NT are operating systems. 

Network Interface Cards, also called adapter cards. Serves as the interface between the computer and the network cable for sending and receiving data. 

Any device that communicates with the network. Nodes include computers, servers, printers, modems, hubs, and routers. A network segment consists of one or more nodes.

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Open Transport 
Macintosh networking protocol starting with Macintosh Operating System version 7.5.3. 

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A unit of transmitted information containing specific protocols and codes that allows precise sending and receiving of information from one networked node to another. 

PC Card 
Communication cards the size of a credit card that fit into the small PC Card slot of portable computers or other networking devices. Formerly called PCMCIA cards, these adapters offer Ethernet access, data/fax/modem capability and other services to portable computers. 

Peripheral Component Interconnect bus architecture. This is a type of slot on computer motherboards (the main board in the computer) into which network interface cards, video cards and other peripherals are inserted. Because of fast speed and easy setup, PCI slots have become the most common today. (see ISA) 

peer to peer 
A network computing system in which all computers are treated as equals on the network. Individual computers may share hard drives, CD-ROM drives, and other storage devices with the other computers on the network. This is different than a client/server setup in which most of the computers (clients) tend to share resources from one main computer (the server). 

Equipment such as disk drives, CD-ROM drives, modems, printers, fax machines, etc. that are connected to a computer. 

A process used to send data packets over a TCP/IP network to test whether the hardware and software is working properly. The ping program is available in the Windows operating system and is available in shareware forms for Macs. 

Plug and Play 
An identifying standard in the PC market that assures the user that the product is as simple or automatic to install as possible; both hardware and software installation. Because this often does not work as well as claimed, it is also commonly known and "plug and pray." 
Point-to-Point Tunneling Protocol (PPTP) 
PPTP is a network protocol that allows users to establish via an IP-network (usually over the Internet, but also possible via Intranets) a secure connection by encapsulating inside the IP-packet an encrypted private protocol, which can be NetBEUI, IPX or TCP/IP. Microsoft has implemented PPTP as VPN, or Virtual Private Networking. 

Processor Direct Slot (PDS) 
An adapter slot available on some Macintoshes that connects directly to the motherboard. In these computers, network interface cards connect to the PDS slot. 

Procedures or rules that control the way information is sent or received over the network. 

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Random Access Memory. The main memory in a PC. 

A network device that regenerates signals so they can extend the cable length. 

ring topology 
A basic networking topology where all nodes are connected in a circle, with no terminated ends on the cable. 

A standard telephone modular connector. 

RJ-45 jack 
The connector on the back of a computer or printer that accepts the RJ-45 plug; looks much like a modular telephone jack. 

RJ-45 plug 
The connector on the end of 10BASE-T or 100BASE-T twisted-pair cabling; looks much like a modular telephone plug. 

Read Only Memory. 

A complex network device used to connect two or more networks together. A router reads information sent along the network and determines its correct destination.

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Small Computer System Interface. This is a standard port for connecting peripherals on Macintosh computers. Also available for PCs. 

seed router 
A seed router supplies routing information (network numbers and ranges, zone names, etc.) to the network. 

A segment consists of one or more nodes. Segments are connected to subnets by hubs and repeaters. 

serial port 
A standard port on the Macintosh for connecting external devices to the computer for either LocalTalk or high-speed serial communications. 

A computer that provides shared resources to network users. 

server-based network 
A network in which all client computers use a dedicated central server computer for network functions such as storage, security and other resources. 

shared data 
Files on the server that can be shared across the network. 

shared Ethernet 
Standard 10BASE-T Ethernet method of sending data to a hub which then rebroadcasts this data to every port on the network until it reaches its destination. 

shared resources 
Files, printers, peripherals and other services that can be shared across the network. 

star topology 
A networking setup used with 10BASE-T cabling and a hub where each node on the network is connected to the hub like points of a star. (See bus topology.) 

store and forward 
The most accurate data transferring technique that examines each packet of a transmission to verify accuracy, and ensuring bad or misaligned packets are eliminated, then sends it to its destination. When the network is busy, the packet is stored until the network is able to carry the traffic and packets are transmitted without error. 

A network segment connected by hubs or repeaters. Subnets can stand alone or can be connected to other subnetworks onto a larger network. 

switched Ethernet 
Unlike shared Ethernet, it provides a private connection between two nodes on a network, speeding up the rate at which data is sent along the network and eliminating collisions. Switched connections allow full duplex, which means network nodes can send and receive data at the same time. This doubles the theoretical "speed limit" of Ethernet and Fast Ethernet, maxing out in the latter at 200Mbps.

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Transmission Control Protocol/Internet Protocol. Standard networking protocol used in UNIX environments. Almost always used together, they are called TCP/IP. A networking protocol with the ability to connect different elements. 

A resistor at each end of an Ethernet coax, or thinnet, cable that absorbs energy to prevent reflected energy back along the cable (signal bounce). It is usually attached to an electrical ground at one end. 

thick Ethernet cable 
Also called "standard Ethernet," thick Ethernet refers to industry-standard Ethernet cable or any other cable that uses the IEEE 802.3 Media Access Unit (MAU) interface. Also called 10BASE-5. 

thin Ethernet cable 
Also called "cheaper net," or 10BASE-2, thin Ethernet refers to thin Ethernet cable or its equivalent (IEEE 802.3 10BASE2) that connects to the Ethernet cable system with a cylindrical BNC connector. Usually quarter-inch black coaxial cable, identified by type such as RG-58/U. 

A wiring configuration used for a network. Examples are rings, stars, bus, and so on. 

Derived from transmitter/receiver, a transceiver is a device that sends and receives signals, that can connect a computer to the network, such as a network interface card. 

twisted-pair cable 
A cable used for both network communications and telephone communications. Also known as UTP (unshielded twisted pair) and 10BASE-T/100BASE-T cable.

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Unshielded twisted pair. Also referred to as 10BASE-T or 100BASE-T network cable. 

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Virtual Private Network (VPN) 
VPN is Microsoft's implementation of Point-to-Point Tunneling Protocol (PPTP), a protocol that provides a secure connection via the Internet. Virtual Private Networks allow computers to use the public Internet backbone as a channel for private data communication. With encryption and encapsulation technology, a VPN creates a private passageway through the Internet. VPNs allow remote offices, company road warriors, and even businesses' customers to use the Internet, rather than pricey private lines, to reach company networks. 

Virtual Private Network Adapter 
VPN Adapter is the device setup in Microsoft networking (Windows 95/98 or Windows NT) that provides services for a Virtual Private Network. In most cases, it is a dial-up adapter (or modem) configured specifically for the VPN. 

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Wide Area Network. A sophisticated network that extends beyond a single building, and often extends across a city, state or farther. 

Nodes connected to a hub or switch to form a small communication grouping for the purposes of networking. 

World Wide Web. The Internet's multimedia service containing countless areas of information, documentation, entertainment, as well as business and personal home pages. 
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A logical grouping of devices in an internet that makes it easier for users to locate network services. Zones are defined during the router setup.

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