1000BaseTX: Ethernet specification for unshielded twisted pair cabling that is used to transmit data at 1 Gbps (gigabits per second) with a distance limitation of 220 meters per segment.
100BaseT: Ethernet specification for unshielded twisted pair cabling that is used to transmit data at 100 Mbps (megabits per second) with a distance limit of 100 meters per segment.
10Base2: Ethernet specification for thin coaxial cable, transmits signals at 10 Mbps (megabits per second) with a distance limit of 185 meters per segment.
10Base5: Ethernet specification for thick coaxial cable, transmits signals at 10 Mbps (megabits per second) with a distance limit of 500 meters per segment.
10BaseF: Ethernet specification for fiber optic cable, transmits signals at 10 Mbps (megabits per second) with a distance limit of 2000 meters per segment.
10BaseT: Ethernet specification for unshielded twisted pair cable (category 3, 4, or 5), transmits signals at 10 Mbps (megabits per second) with a distance limit of 100 meters per segment.
802.11: An IEEE specification for wireless networking in the 2.4GHz frequency range with a maximum 2Mbps data transfer rate.
802.11a: An IEEE specification for wireless networking in the 5GHz frequency range with a maximum 54Mbps data transfer rate. The 802.11a specification also includes QoS (Quality of Service) technology to protect voice and multimedia data. At this time no 802.11a products are available on the market.
802.11e: A proposed IEEE specification that will include QoS (Quality of Service) features, particularly the ability to recognize and prioritize different types of data, and security provisions. The specification draft has not yet been ratified by the IEEE.
Access Point: A device that acts as a gateway between a wired network and a wireless network. They act as a central point for wireless devices to connect to an Ethernet LAN.
Adapter: An electronic card installed into a computer or plugged in via USB or a CardBus which allows the PC to get onto a network.
AppleTalk: Apple Computer’s network protocol originally designed to run over LocalTalk networks, but can also run on Ethernet and Token Ring.
Backbone: A central part of a large network which connects two or more major subnetworks together. Acts as a major path for data transmission.
Bandwidth: The amount of data which can flow through a line at once. The capacity for a network to flow data.
Bidirectional: Describes the ability to support data flowing in two directions at once.
Bit: Binary digit in the binary numbering system. Its value can be 0 or 1. In an 8-bit character scheme, it takes 8 bits to make a byte (character) of data.
Bluetooth: A technology capable of linking two computers wirelessly. Has a range of about 30 feet. Also used for cell phones and PDAs.
BNC Connector (Bayone-Neill-Concelman): Standard connector used to connect 10Base2 coaxial cable.
Bridge: Devices that connect and pass packets between two network segments that use the same communications protocol.
Broadband: Refers to high speed internet technologies like DSL or cable which are capable of transmitting multiple data streams at once.
Cable: Transmission medium of copper wire or optical fiber wrapped in a protective cover.
CardBus: An expansion slot on notebook computers to adding add-on devices via a card-like slot. Requires Windows 98 or higher.
CAT3 Cable: Twisted pair of copper cables for transmitting data on 10 Mbps networks.
CAT5 Cable: Twisted pair of copper cables for transmitting data on 10/100 Ethernet.
CAT5e Cable: Twisted pair of copper cables for transmitting data on 10/100 Ethernet or at 1 Gbps.
CAT6 Cable: Twisted pair of copper cables for transmitting data on 10/100 Ethernet or at 1 Gbps.
Client/Server: A networking system in which one or more file servers (Server) provide services; such as network management, application and centralized data storage for workstations (Clients).
Coaxial Cable: Cable consisting of a single copper conductor in the center surrounded by a plastic layer for insulation and a braided metal outer shield.
Concentrator: A device that provides a central connection point for cables from workstations, servers, and peripherals. Most concentrators contain the ability to amplify the electrical signal they receive.
CSMA/CA: Carrier Sense Multiple Access Collision Avoidance is a network access method in which each device signals its intent to transmit before it actually does so. This prevents other devices from sending information, thus preventing collisions from occurring between signals from two or more devices. This is the access method used by LocalTalk.
CSMA/CD: Carrier Sense Multiple Access Collision Detection is a network access method in which devices that are ready to transmit data first check the channel for a carrier. If no carrier is sensed, a device can transmit. If two devices transmit at once, a collision occurs and each computer backs off and waits a random amount of time before attempting to retransmit. This is the access method used by Ethernet.
DIN: A plug and socket connector consisting of a circular pattern of pins in a metal sleeve. This type of connector is commonly seen on keyboards.
Domain Name System (DNS): A program which translates human-readable web addressed into the IP addresses by which the internet operates. Maintained by a collection of internet servers throughout the world.
Dumb Terminal: Refers to devices that are designed to communicate exclusively with a host (main frame) computer. It receives all screen layouts from the host computer and sends all keyboard entry to the host. It cannot function without the host computer.
Dynamic Host Control Protocol (DHCP): A utility that allows a server to assign IP addresses to network devices automatically on the fly.
E-mail: An electronic mail message sent from a host computer to a remote computer.
End User: Refers to the human executing applications on the workstation.
Ethernet: A network protocol invented by Xerox Corporation and developed jointly by Xerox, Intel and Digital Equipment Corporation. Ethernet networks use CSMA/CD and run over a variety of cable types at 10 Mbps (megabits per second).
Expansion Slot: Area in a computer that accepts additional input/output boards to increase the capability of the computer.
Fast Ethernet: A new Ethernet standard that supports 100 Mbps using category 5 twisted pair or fiber optic cable.
Fiber Distributed Data Interface (FDDI): A network protocol that is used primarily to interconnect two or more local area networks, often over large distances.
Fiber Optic Cable: A cable, consisting of a center glass core surrounded by layers of plastic, that transmits data using light rather than electricity. It has the ability to carry more information over much longer distances.
File Server: A computer connected to the network that contains primary files/applications and shares them as requested with the other computers on the network. If the file server is dedicated for that purpose only, it is connected to a client/server network. An example of a client/server network is Novell Netware. All the computers connected to a peer-to-peer network are capable of being the file server. Two examples of peer-to-peer networks are LANtastic and Windows for Workgroups.
Firewall: A system that secures a network by acting as a barrier between the network and outside networks. Prevents unauthorized network access from the outside.
Firewire: The IEEE 1394 standard for input/output technology for connecting high-speed multimedia peripherals to a computer.
Frame Relay: A network technology that transmits data in packets or envelopes in bursts at speeds of 56 Kbps.
Gateway: Hardware or software for connecting networks which use different technologies, such as connecting Ethernet to a power-line network.
Gigabit Ethernet: An Ethernet protocol that raises the transmission rates to 1 Gbps (gigabits per second). It is primarily used for a high speed backbone of a network.
Gigabyte (GB): One billion bytes of information. One thousand megabytes.
Hops Count: A measure between two points on a network of how many network adapter cards a transmission crosses. In short, how many jumps did the data cross through to get to it’s destination.
Hub: A hardware device that contains multiple independent but connected modules of network and internetwork equipment. Hubs can be active (where they repeat signals sent through them) or passive (where they do not repeat but merely split signals sent through them).
IEEE 802.11b: International standard networking technology for LAN wireless implementations that revised 802.11 to increase transmission speeds to 11Mbps.
IEEE 802.3: International standard networking technology for Ethernet implementations.
Infrared: Electromagnetic waves whose frequency range is above that of microwaves, but below that of the visible spectrum.
Internet: A global network of networks used to exchange information using the TCP/IP protocol. It allows for electronic mail and the accessing ad retrieval of information from remote sources.
Internet Protocol (IP) Address: A string of numbers assigned to each device on a network. It acts as a “street address” for the computer on the network so that other computers can locate it.
Internet Service Provider (ISP): A company which provides access to the internet, usually for a monthly fee.
Intranet: Network internal to an organization that uses Internet protocols.
IP Telephony: A technology that supports the transmission of voice, data and video over an IP-based network. Voice-Over IP (VOIP) is one technology in this area.
LAN (Local Area Network): A network connecting computers in a relatively small area such as a building.
Linear Bus: A network topology in which each node attaches directly to a common cable.
MAN (Metropolitan Area Network): A network connecting computers over a large geographical area, such as a city or school district.
Mapping: Assigning a PC to a shared drive or a printer port on a network.
MAU (Multistation Access Unit): A Token Ring wiring hub.
Megabits per second (Mbps): A measure of transmission speed over network cables. 1 million bits per second.
Modem (Modulator/Demodulator): Devices that convert digital and analog signals. Modems allow computer data (digital) to be transmitted over voice-grade telephone lines (analog).
Multiplexer: A device that allows multiple logical signals to be transmitted simultaneously across a single physical channel.
Network Interface Card (NIC): A board that provides network communication capabilities to and from a computer.
Network Modem: A modem connected to a Local Area Network (LAN) that is accessible from any workstation on the network.
Network Operating System (NOS): Operating system designed to pass information and communicate between more than one computer. Examples include AppleShare, Novell NetWare, and Windows NT Server.
Node: End point of a network connection. Nodes include any device attached to a network such as file servers, printers, or workstations.
Node Devices: Any computer or peripheral that is connected to the network.
Noise: Unneeded network signals that degrade the network signal.
Packet: A segment of data sent over a network. The structure of the packet is dictated by the protocol being used.
PCMCIA: An expansion slot found in many laptop computers.
Peer-to-Peer Network: A network in which resources and files are shared without a centralized management source.
Physical Topology: The physical layout of the network; how the cables are arranged; and how the computers are connected.
Point-to-Point: A direct link between two objects in a network.
Ports: A connection point for a cable.
Protocol: A formal description of a set of rules and conventions that govern how devices on a network exchange information.
Proxy server: A server which acts as the public face for a network, preventing direct communication between two or more networks but forwards allowable data to remote server and/or responds to data requests directly. In short, a server which acts as a go-between.
Repeater: A device used in a network to strengthen a signal as it is passed along the network cable.
RJ-11: A standard phone-cord connector.
RJ-45: Standard connectors used for unshielded twisted-pair cable used on Ethernet networks.
Router: A device that routes information between interconnected networks. It can select the best path to route a message, as well as translate information from one network to another. It is similar to a superintelligent bridge.
Segment: Refers to a section of cable on a network. In Ethernet networks, two types of segments are defined. A populated or trunk segment is a network cable that has one or more nodes attached to it. A link segment is a cable that connects a computer to an interconnecting device, such as a repeater or concentrator, or connects a interconnecting device to another interconnecting device.
Server: A computer that is set up to provide resources to other computers on a network.
Shielded Twisted Pair cable: A cable consisting of two or more copper wire pairs which are wrapped around each other and then covered in a casing to provide insulation. Used on networks.
Speed of Data Transfer: The rate at which information travels through a network, usually measured in megabits per second.
Star Topology: LAN topology in which each node on a network is connected directly to a central network hub or concentrator.
Star-Wired Ring: Network topology that connects network devices (such as computers and printers) in a complete circle.
Subnet: A network segment that is created to simplify addressing and is connected to a central network through a router, hub or gateway.
Switch: A type of hub that allows multiple devices to share the same bandwidth (like a hub) but intelligently routes data packets to only those devices for which it is intended.
TCP/IP: Transmission Control Protocol / Internet Protocol. The standard protocol used today on the internet.
Terminator: A device that provides electrical resistance at the end of a transmission line. Its function is to absorb signals on the line, thereby keeping them from bouncing back and being received again by the network.
Thicknet: A thick coaxial cable that is used with a 10Base5 Ethernet LAN.
Thinnet: A thin coaxial cable that is used with a 10Base2 Ethernet LAN.
Token: A special packet that contains data and acts as a messenger or carrier between each computer and device on a ring topology. Each computer must wait for the messenger to stop at its node before it can send data over the network.
Token Ring: A network protocol developed by IBM in which computers access the network through token-passing. Usually uses a star-wired ring topology.
Topology: There are two types of topology: physical and logical. The physical topology of a network refers to the configuration of cables, computers, and other peripherals. Logical topology is the method used to pass the information between workstations. Issues involving logical topologies are discussed on the Protocol chapter
Transceiver (Transmitter/Receiver): A Device that receives and sends signals over a medium. In networks, it is generally used to allow for the connection between two different types of cable connectors, such as AUI and RJ-45.
Tree Topology: LAN topology similar to linear bus topology, except that tree networks can contain branches with multiple nodes.
Twisted Pair: Network cabling that consists of four pairs of wires that are manufactured with the wires twisted to certain specifications. Available in shielded and unshielded versions.
Uplink Port: A connector on a hub, switch or router to allow connection of another hub, switch or router.
USB (Universal Serial Bus) Port: A hardware interface for low-speed peripherals such as the keyboard, mouse, joystick, scanner, printer, and telephony devices.
Virtual Private Network (VPN): A data network created by companies using secured protocols and user authorization. Used to allow remote access to company networks.
WAN (Wide Area Network): A network connecting computers within very large areas, such as states, countries, and the world.
WiFi: Wireless Fidelity.
Workgroup: A collection of workstations and servers on a LAN that are designated to communicate and exchange data with one another.
Workstation: A computer connected to a network at which users interact with software stored on the network.