Chapter 1 Key Terms

Front 1

Bandwidth -

Back 1

A piece of the spectrum occupied by some form of signal, whether it is television, voice, fax data, and so forth.

Front 2

BNC Connectors-

Back 2

a connector used for 10Base2 coaxial cable. Has to be locked into place by turning the locking ring 90 degrees.

Front 3

Bus topology-

Back 3

a network topology that uses a single bus cable that connects all of the computers in line. Bus topology networks must be terminated to prevent signal reflection.

Front 4

Category (CAT) Rating-

Back 4

a grade assigned to cable to help network installers get the right cable for the right network technology. Officially rated in megahertz (MHz), indicating the highest-frequency bandwidth the cable can handle.

Front 5

Cladding-

Back 5

the part of a fiber-optic cable that makes the light reflect down the fiber.

Front 6

Coaxial Cable-

Back 6

a type of cable that contains a central conductor wire surrounded by an insulating material, which in turn is surrounded by a braided metal shield. It is called coaxial because the center wire and the braided metal shield share a common axis or center line.

Front 7

Core-

Back 7

the central glass of the fiber-optic cable that carries the light signal.

Front 8

Crosstalk-

Back 8

electrical signal interference between two cables that are in close proximity of each other.

Front 9

Electromagnetic Interference (EMI)-

Back 9

interference from one device to another, resulting in poor performance in the device's capabilities. This is similar to having static on your TV while running a hair dryer.

Front 10

Fault tolerance-

Back 10

the capability of any system to continue functioning after some part of the system has failed. RAID is an example of a hardware device that provides fault tolerance for hard drives.

Front 11

Fiber-optic cable-

Back 11

a high-speed physical medium for transmitting data that uses light rather than electricity to transmit data and is made of high-purity glass fibers sealed within a flexible opaque tube. Much faster than conventional copper wire.

Front 12

Fully meshed topology-

Back 12

a mesh network where every node is directly connected to every other node.

Front 13

Hybrid topology-

Back 13

a mix or blend of two different topologies. A star-bus topology is a hybrid of the star and bus topologies.

Front 14

IEEE 1284-

Back 14

the IEEE standard for the now obsolete parallel communication.

Front 15

IEEE 1394-

Back 15

IEEE standard for FireWire communication.

Front 16

insulating jacket-

Back 16

the external plastic covering of a fiber-optic cable.

Front 17

logical topology-

Back 17

a network topology defined by signal paths as opposed to the physical layout of the cables.

Front 18

mesh topology-

Back 18

topology in which each computer has a direct or indirect connection to every other computer in a network. Any node on the network can forward traffic to other nodes. Popular in cellular and many wireless networks.

Front 19

modal distortion

Back 19

a light distortion problem unique to multimode fiber-optic cable.

Front 20

multimode fiber (mmf)

Back 20

type of fiber-optic cable that uses LEDs.

Front 21

network topology

Back 21

refers to the way that cables and other pieces of hardware connect to one another.

Front 22

Ohm rating

Back 22

electronic measurement of a cable's or an electronic component's impedance.

Front 23

partially meshed topology

Back 23

a mesh topology in which not all of the nodes are directly connected.

Front 24

physical topology

Back 24

the manner in which the physical components of a network are arranged.

Front 25

plenum

Back 25

usually a space between a building's false ceiling and the floor above it. Most of the wiring for networks is located above in this space. Plenum is also a fire rating for network cabling.

Front 26

point-to-multipoint topology

Back 26

topology in which one device communicates with more than one other device on a network.

Front 27

point-to-point topology

Back 27

a network of two single devices communicating with one another.

Front 28

polyvinyl chloride (PVC)

Back 28

a material used for the outside insulation and jacketing of most cables. Also a fire rating for a type of cable that has no significant fire protection.

Front 29

radio grade rating (RG)

Back 29

ratings developed by the U.S. military to provide a quick reference for the different types of coaxial cables.

Front 30

ring topology

Back 30

a network topology in which all of the computers on the network attach to a central ring of cable.

Front 31

riser

Back 31

fire rating that designates the proper cabling to use for vertical runs between floors of a building.

Front 32

RJ-11

Back 32

type of connector with four-wire UTP connections; usually found in telephone connections

Front 33

RJ-45

Back 33

type of connector with eight-wire UTP connections; usually found in network connections and used for 10/100/1000BaseT networking

Front 34

RS-232

Back 34

the recommended standard (RS) upon which all serial communication takes place on a PC.

Front 35

signaling topology

Back 35

another name for logical topology

Front 36

single-mode fiber

Back 36

fiber-optic cables that use lasers.

Front 37

star-bus topology

Back 37

a hybrid of the star and bus topologies that uses a physical star, where all nodes connect to a single wiring point such as a hub and a logical bus that maintains the Ethernet standards. One benefit of a star-bus topology is fault tolerance.

Front 38

star-ring topology

Back 38

a hybrid of the Token Ring topology and the physical star.

Front 39

star topology

Back 39

a network topology in which all of the computers in the network connect to a central wiring point.

Front 40

unshielded twisted pair (UTP)

Back 40

a popular cabling for telephone and networks composed of pairs of wires twisted around each other at specific intervals. The twists serve to reduce interference (also called crosstalk).

Front 41

10BaseFL

Back 41

fiber-optic implementation of Ethernet that runs at 10 megabits per second (Mbps) using baseband signaling.

Front 42

10BaseT

Back 42

an Ethernet LAN designed to run on UTP cabling. Runs at 10 Mbps and uses baseband signaling. Maximum length for the cabling from NIC to hub is 100 m.

Front 43

802.3 (Ethernet)

Back 43

name coined by Xerox for the first standard of network cabling and protocols. Ethernet is based on a bus topology. The IEEE 802.3 subcommittee defines the current Ethernet specifications.

Front 44

bridge

Back 44

a device that connects two networks and passes traffic between them based only on the node address, so that traffic between nodes on one network does not appear on the other network. For example, an Ethernet bridge only looks at the MAC address Bridges filter and forward frames based on MAC addresses and operate at Layer 2 (Data Link Layer) of the OSI seven-layer model.

Front 45

bridge loop

Back 45

a negative situation in which bridging devices (usually switches) are installed in a loop configuration, causing frames to loop continuously.

Front 46

broadcast domain

Back 46

a network of computers that will hear each other's broadcasts. The older term "collision domain" is the same, but rarely used today.

Front 47

carrier sense multiple access with collision detection (CSMA/CD)

Back 47

access method that Ethernet systems use in LAN technologies, enabling frames of data to flow through the network and ultimately reach address locations. Known as a contention protocol, hosts on CSMA/CD networks send out data without checking to see if the wire is free first. If a collision occurs, then both hosts wait a random time period before re-transmitting the data.

Front 48

crimper

Back 48

also called a crimping tool, used to secure a crimp (an RJ-45 connector) onto the end of a cable.

Front 49

crossover cable

Back 49

a special UTP cable used to interconnect hubs/switches or to connect network cards without a hub/switch. Crossover cables reverse the sending and receving wire pairs from one end to the other.

Front 50

Ethernet

Back 50

name coined by Xerox for the first standard of network cabling and protocols. Ethernet is based on a bus topology.

Front 51

frame

Back 51

a defined series of binary data that is the basic container for a discrete amount of data moving across a network. Frames are created at Layer 2 of the OSI model.

Front 52

frame check sequence (FCS)

Back 52

a sequence of bits placed in a fram that is used to check the primary data for errors.

Front 53

full-duplex

Back 53

any device that can send and receive data at the same time.

Front 54

half-duplex

Back 54

any device that can only send or receive data at any given moment.

Front 55

hub

Back 55

an electronic device that sits at the center of a star topology network, providing a common point for the connection of network devices.

Front 56

MAC addresses

Back 56

unique 48-bit address assigned to each network card. The Data Link layer of the OSI model uses these for locating machines.

Front 57

media converter

Back 57

a device that lets you interconnect different types of Ethernet cable.

Front 58

multimode fiber (mmf)

Back 58

type of fiber-optic cable that uses LED.

Front 59

node

Back 59

NIC

Front 60

pad

Back 60

extra data added to an Ethernet frame to bring the data up to minimum required size of 64 bytes.

Front 61

port

Back 61

that portion of a computer through which a peripheral device may communicate. On a network hub, it is the connector that receives the wire link from a node.

Front 62

preamble

Back 62

a 64-bit series of alternating 1s and 0s, ending with 11, that begins every Ethernet frame. The preamble gives a receiving NIC time to realize a frame is coming and to know exactly where the frame starts.

Front 63

promiscuous mode

Back 63

a mode of operation for a NIC in which the NIC processes all frames that it sees on the cable.

Front 64

repeater

Back 64

a device that takes all of the frames it receives on one Ethernet segment and re-creates them on another Ethernet segment.

Front 65

sniffer

Back 65

diagnostic program that can order a NIC to run in promiscuous mode.

Front 66

Source Address Table (SAT)

Back 66

an electronic table of the MAC address of each computer connected to a switch

Front 67

Spanning Tree Protocol (STP)

Back 67

a protocol that enables switches to detect and repair bridge loops automatically.

Front 68

straight-through cable

Back 68

a cable that enables you to connect the uplink ports of two hubs together.

Front 69

switch

Back 69

a device that filters and forwards traffic based on some criteria. A bridge and a router are both examples of switches.

Front 70

TIA/EIA 568A

Back 70

one of two four-pair UTP crimping standards for 10/100/1000BaseT networks.

Front 71

TIA/EIA 568B

Back 71

one of two four-pair UTP crimping standards for 10/100/1000BaseT networks.

Front 72

uplink port

Back 72

port on a hub that enables you to connect two hubs together using a straight-through cable.

Front 73

10GBaseER/EW

Back 73

A 10 GbE standard using single-mode fiber with maximum cable length up to 40 km.

Front 74

10GBaseLR/LW

Back 74

a 10 GbE standard using multi-mode fiber with maximum cable length up to 10 km.

Front 75

10GBaseSR/10GBaseSW

Back 75

a 10 GbE standard using multi-mode fiber. maximum cable length up to 300 meters.

Front 76

10GBaseT

Back 76

a 10 GbE standard designed to run on CAT 6a UTP cabling. Maximum cable length of 100 m.

Front 77

10 Gigabit Ethernet (10 GbE)

Back 77

currently the fastest Ethernet designation available, with a number of fiber-optic and copper standards.

Front 78

100BaseFX

Back 78

an Ethernet LAN designed to run on fiber-optic cabling. Runs at 100 Mbps and uses baseband signaling.

Front 79

100BaseT

Back 79

an Ethernet LAN designed to run on UTP cabling. Runs at 100 Mbps, uses baseband signaling, and uses two pairs of wires on CAT 5 or better cabling.

Front 80

100BaseT4

Back 80

an Ethernet Lan designed to run on UTP cabling. Runs at 100 Mbps and uses four-pair CAT 3 or better cabling. Made obsolete by 100BaseT

Front 81

100BaseTX

Back 81

the technically accurate but little-used name for 100BaseT

Front 82

1000BaseCX

Back 82

a gigabit Ethernet standard using unique copper cabling, with a 25-m maximum cable distance.

Front 83

1000BaseLX

Back 83

a gigabit Ethernet standard using single-mode fiber cabling, witha 220- to 500-m maximum cable distance.