Module 05 Flashcards
1
Q
A measure of the number of times an electrical signal changes state per second.
A
Frequency
2
Q
A measure of the amount of data that could theoretically be transmitted during a given period of time.
A
Bandwidth
3
Q
The amount of data that a medium transmits during a given period of time. Throughput is usually measured in Mbps (megabits per second, which is 1,000,000 bits) or Gbps (gigabits per second).
A
Throughput
4
Q
The process of altering an analog signal to carry data.
A
Modulation
5
Q
The process of converting data into a digital signal for transmission.
A
Encoding
6
Q
A measure of the degradation or distortion of a signal.
A
dB (decibel) loss
7
Q
The loss of a signal’s strength as it travels away from its source.
A
Attenuation
8
Q
A device used to regenerate a digital signal in its original form. Repeaters operate at the physical layer of the OSI model.
A
Repeater
9
Q
The delay between the transmission of a signal and its receipt.
A
Latency
10
Q
The length of time it takes for a packet to go from sender to receiver, then back from receiver to sender. RTT is usually measured in milliseconds.
A
RTT (round trip time)
11
Q
A transmission flaw caused by packets experiencing varying amounts of delay and arriving out of order. Also called PDV (packet delay variation).
A
Jitter
12
Q
A type of transmission in which signals may travel in both directions over a medium simultaneously; also called, simply, duplex.
A
Full-duplex
13
Q
A type of transmission in which signals may travel in both directions over a medium simultaneously.
A
Duplex
14
Q
A problem that occurs when neighboring devices are using different speed or duplex configurations and results in failed transmissions.
A
Speed and duplex mismatch
15
Q
A form of transmission that allows multiple signals to travel simultaneously over one medium.
A
Multiplexing
16
Q
A method of multiplexing that assigns a time slot in the flow of communications to every node on the network and, in that time slot, carries data from that node.
A
TDM (time division multiplexing)
17
Q
A type of multiplexing that assigns time slots to nodes (similar to TDM), but then adjusts these slots according to priority and need.
A
STDM (statistical time division multiplexing)
18
Q
A type of multiplexing that assigns a unique frequency band to each communications subchannel. Signals are modulated with different carrier frequencies and then multiplexed to simultaneously travel over a single channel.
A
FDM (frequency division multiplexing)
19
Q
A multiplexing technique in which each signal on a fiber-optic cable is assigned a different wavelength, which equates to its own subchannel.
A
WDM (wavelength division multiplexing)
20
Q
A type of WDM multiplexing that supports full-duplex light transmissions.
A
Bidirectional WDM
21
Q
A multiplexing technique used over single-mode or multimode fiber-optic cable in which each signal is assigned a different wavelength for its carrier wave.
A
DWDM (dense wavelength division multiplexing or dense WDM)
22
Q
A multiplexing technique used over single-mode or multimode fiber-optic cable in which each signal is assigned a different wavelength for its carrier wave.
A
CWDM (coarse wavelength division multiplexing or coarse WDM)
23
Q
A type of cable that consists of a central metal conducting core, surrounded by an insulator, shielding, and an outer cover. Today coaxial cable, called “coax” for short, is mostly used to connect cable Internet and cable TV systems.
A
Coaxial cable
24
Q
A measure of the opposition to a current’s flow through a cable, expressed in ohms.
A
Impedance
25
A type of coaxial cable with an impedance of 75 ohms and an 18 AWG core conductor. RG-6 is used for television, satellite, and broadband cable connections.
RG-6
26
A connector used to terminate coaxial cable that transmits television and cable broadband signals.
F-connector
27
A coaxial cable connector type that uses a turn-and-lock (or bayonet) style of coupling.
BNC connector
28
A type of copper cable that looks very similar to coaxial cable but has two or more cores, or conductors, inside the cable. Called twinax for short.
Twinaxial cable
29
A type of cable similar to telephone wiring that consists of color-coded pairs of insulated copper wires, each with a diameter of 0.4 to 0.8 mm. Every two wires are twisted around each other to form pairs, and all the pairs are encased in a plastic sheath.
Twisted-pair
30
A type of Ethernet network that is capable of 100-Mbps throughput.
Fast Ethernet
31
A type of Ethernet network that is capable of 1000-Mbps, or 1-Gbps, throughput. Requires Cat 5e or higher cabling.
Gigabit Ethernet
32
The number of twists per meter or foot in a twisted-pair cable.
Twist ratio
33
A form of UTP that contains four wire pairs and supports up to 100-Mbps throughput and a 100-MHz signal rate. Required minimum standard for Fast Ethernet.
Cat 5 (Category 5)
34
A higher-grade version of Cat 5 wiring that supports a signaling rate of up to 350 MHz and a maximum throughput of 1 Gbps, making it the required minimum standard for Gigabit Ethernet.
Cat 5e (Enhanced Category 5)
35
A twisted-pair cable that contains four wire pairs, each wrapped in foil insulation. Additional foil insulation can cover the bundle of wire pairs, and a fire-resistant plastic sheath might cover the second foil layer. The foil insulation provides excellent resistance to crosstalk and enables Cat 6 to support a signaling rate of 250 MHz and throughput up to 10 Gbps.
Cat 6 (Category 6)
36
A higher-grade version of Cat 6 wiring that further reduces attenuation and crosstalk, and allows for potentially exceeding traditional network segment length limits.
Cat 6a (Augmented Category 6)
37
A twisted-pair cable that contains multiple wire pairs, each separately shielded then surrounded by another layer of shielding within the jacket, allowing throughput up to 100 Gbps at very short distances. Cat 7 is not included in the TIA/EIA standards.
Cat 7 (Category 7)
38
A higher-grade version of Cat 7 wiring that might support up to 100-Gbps throughput at short distances and up to 1000-MHz signal rate but has not been accepted as a TIA/EIA standard.
Cat 7a (Augmented Category 7)
39
A twisted-pair cable that relies on improved and extensive shielding and is optimized for short-distance backbone connections within the data center.
Cat 8 (Category 8)
40
Cabling designed to withstand high temperatures, offers a highly fire-retardant jacket, and burns with less smoke that is nontoxic.
Plenum-grade cable
41
Cabling coated with a fire-retardant jacket that is thicker than typical network cables to ease the cable’s insertion through risers in buildings or between floors.
Riser-rated cable
42
The standard connector used with shielded twisted-pair and unshielded twisted-pair cabling.
RJ-45 (registered jack 45)
43
The standard connector used with unshielded twisted-pair cabling (usually Cat 3) to connect analog telephones.
RJ-11 (registered jack 11)
44
A standard pinout for RJ-45 plugs required by the federal government on all federal contracts. Also called T568A.
TIA/EIA-568A
45
A standard pinout for RJ-45 plugs commonly used in homes and businesses. Also called T568B.
TIA/EIA-568B
46
The pin numbers and color-coded wire assignments used when terminating a cable or installing a jack, as determined by the TIA/EIA standard.
Pinouts
47
A twisted-pair patch cable in which the wire terminations in both connectors follow the same scheme.
Straight-through cable
48
A relatively short section (usually between 3 and 25 feet) of cabling with connectors on both ends.
Patch cable
49
A connector used with twisted-pair wiring on an Ethernet network.
MDI (medium dependent interface)
50
An alternative connector used with twisted-pair wiring on an Ethernet network that reverses the transmit and receive wires.
MDI-X (MDI crossover)
51
Ports on newer devices that automatically negotiate the transmit and receive wires between devices.
auto-MDI-X
52
A troubleshooting tool that plugs into a port (for example, an RJ-45 or fiber-optic port) and crosses the transmit line with the receive line, allowing outgoing signals to be redirected back into the computer for testing. Also called a loopback plug.
Loopback adapter
53
A twisted-pair patch cable in which the termination locations of the transmit and receive wires on one end of the cable are reversed as compared with the other end.
Crossover cable
54
A problem caused by mismatched pinout standards, resulting in near end crosstalk.
TX/RX reverse
55
A cable used to connect a computer to the console port of a router.
Rollover cables
56
A cable used to connect a computer to the console port of a router.
Console cables
57
A pliers-shaped tool that makes a clean cut through a cable.
Wire cutter
58
Heavy-duty scissors that make a clean cut through a cable.
Snips
59
A tool used to pull off the protective covering of a cable without damaging the wires inside.
Cable stripper
60
A tool used to push the pins of a connector into the wires of a cable so they pierce the wire’s insulation.
Cable crimper
61
A method of delivering up to 15.4 watts to devices using Ethernet connection cables.
PoE (Power over Ethernet)
62
A method of delivering more current (up to 25.5 watts) than PoE does to devices using Ethernet connection cables.
PoE+
63
Various standards used to rate the performance expectations of a cable, NIC, or other device.
Ethernet standards
64
A physical layer standard for networks that specifies 10-Mbps transmission over twisted-pair cable.
10BASE-T
65
A physical layer standard for networks that specifies 100-Mbps transmission over twisted-pair cable. Also called 100BASE-TX.
100BASE-T
66
A physical layer standard for networks that specifies 100-Mbps transmission over twisted-pair cable. Also called 100BASE-T.
100BASE-TX
67
A physical layer standard for achieving 1 Gbps over twisted-pair cable.
1000BASE-T
68
A physical layer standard for achieving 10-Gbps data transmission over twisted-pair cable.
10GBASE-T
69
A physical layer standard for achieving 40-Gbps data transmission over twisted-pair cable.
40GBASE-T
70
A cool-burning, long-lasting technology that creates light by the release of photons as electrons move through a semiconductor material.
LED (light-emitting diode)
71
The glass or plastic shield around the core of a fiber-optic cable. Cladding reflects light back to the core in patterns that vary depending on the transmission mode.
Cladding
72
The degradation of a light signal on a fiber-optic network as it travels away from its source.
Optical loss
73
A type of fiber-optic cable with a narrow core of 8 to 10 microns in diameter that carries light pulses along a single path from one end of the cable to the other end.
SMF (single mode fiber)
74
A type of fiber-optic cable containing a core that is usually 50 or 62.5 microns in diameter, over which many pulses of light generated by a laser or LED (light-emitting diode) travel at different angles.
MMF (multimode fiber)
75
A device on a rack where fiber cables converge, connect with each other, and connect with fiber-optic terminal equipment from the ISP.
FDP (fiber distribution panel)
76
A tool used to melt the tips of two fibers together so light can pass cleanly through the joint.
Fusion splicer
77
The extended tip of a fiber-optic cable connector that encircles the fiber strand to keep it properly aligned and ensure that it makes contact with the receptacle in a jack or other connector.
Ferrule
78
The return of a light signal back into a fiber-optic cable that is transmitting the signal. Back reflection is measured as optical loss in dB (decibels).
Back reflection
79
A type of ferrule in which the tip has been highly polished, thereby increasing the efficiency of the connection.
UPC (ultra-physical contact)
80
The latest advancement in ferrule technology that uses the principles of reflection to its advantage by placing the end faces of the highly polished ferrules at an angle to each other, thus reducing the effect of back reflection.
APC (angled physical contact)
81
The most common 1.25-mm ferrule connector, which is used with single-mode, fiber-optic cable.
LC (local connector)
82
A connector with a 2.5-mm ferrule that is used with single-mode, fiber-optic cable.
SC (subscriber connector or standard connector)
83
A connector with a 2.5-mm ferrule that is used with single-mode, fiber-optic cable.
ST (straight tip)
84
The most common type of connector used with multimode fiber-optic cable.
MT-RJ (mechanical transfer-registered jack)
85
A device that enables networks or segments running on different media to interconnect and exchange signals.
Media converter
86
A modular interface that can be inserted in a switch to connect its motherboard with an external, fiber-optic cable.
Transceivers
87
A component that can be installed or removed without disrupting operations.
Hot-swappable
88
A standard hot-swappable network interface used to link a connectivity device’s backplane with fiber-optic or copper cabling.
SFP (small form-factor pluggable)
89
A type of SFP that can send and receive data at rates of up to 10 Gbps.
XFP (10 Gigabit small form-factor pluggable)
90
A type of SFP that can send and receive data at rates of up to 16 Gbps.
SFP+
91
A fiber-optic transceiver that complies with the 802.3ba standard, squeezing four channels in a single transceiver and supporting data rates up to 40 Gbps (4 × 10 Gbps).
QSFP (quad small form-factor pluggable)
92
Generally the same technology as QSFP while supporting data rates over 40 Gbps.
QSFP+
93
A fiber-optic transceiver intended for 100-Gbps network connections.
CFP (centum form-factor pluggable)
94
A physical layer standard for networks that specifies 100-Mbps transmission over fiber-optic cable using baseband transmission. The SX represents its reliance on short wavelengths of 850 nanometers.
100BASE-SX
95
A physical layer standard for networks that specifies 100-Mbps transmission over fiber-optic cable using baseband transmission. The FX represents its support of Fast Ethernet speeds.
100BASE-FX
96
A physical layer standard for networks that specifies 1-Gbps transmission over fiber-optic cable using baseband transmission. The SX represents its reliance on short wavelengths of 850 nanometers.
1000BASE-SX
97
A physical layer standard for networks that specifies 1-Gbps transmission over fiber-optic cable using baseband transmission. The LX represents its reliance on long wavelengths of 1300 nanometers.
1000BASE-LX
98
`A physical layer standard for networks that specifies 10-Gbps transmission over fiber-optic cable using baseband transmission. The SR represents its support of short-range transmissions.
10GBASE-SR
99
A physical layer standard for networks that specifies 10-Gbps transmission over fiber-optic cable using baseband transmission. The LR represents its support of long-range transmissions.
10GBASE-LR
100
A measure of the highest frequency of signal a multimode fiber-optic cable can support over a specific distance. Modal bandwidth is measured in MHz-km.
Modal bandwidth
101
The calculation of power a transceiver must use to overcome all anticipated losses along the length of a fiber-optic connection.
Optical link budget
102
A small electronic device that issues a signal on a wire pair. When used in conjunction with a tone locator, it can help locate the termination of a wire pair. Also called a toner.
Tone generator (or toner)
103
A small electronic device that emits a tone when it detects electrical activity on a wire pair. When used in conjunction with a tone generator, it can help locate the termination of a wire pair. Also called a probe.
Tone locator (or probe)
104
A simple instrument that can measure multiple characteristics of an electric circuit, including its resistance, voltage, and impedance.
Multimeter
105
An unwanted connection, such as when exposed wires touch each other.
Short circuit
106
A circuit in which necessary connections are missing, such as occurs when a wire breaks.
Open circuit
107
The ability of a cable to carry a signal to its destination.
Continuity
108
An instrument that tests whether voltage (or light, in the case of fiber-optic cable) issued at one end of a cable can be detected at the opposite end of the cable. Also called cable checker or cable tester.
Continuity testers
109
A device that tests cables for one or more of the following conditions: continuity, segment length, distance to a fault, attenuation along a cable, near-end crosstalk, and termination resistance and impedance.
Cable tester
110
A test that indicates if each pin on one end of a cable is paired with the appropriate pin on the other end
Wire map test
111
A troubleshooting tool that tests cables for continuity, but can also measure crosstalk, attenuation, and impedance; identify the location of faults; and store or print cable testing results. Also called line tester, certifier, or network tester.
Cable performer tester
112
A high-end instrument for testing the qualities of a cable.
TDR (time domain reflectometer)
113
A performance testing device for use with fiber-optic networks, which can accurately measure the length of the fiber, locations of faults, and many other characteristics.
OTDRs (optical time domain reflectometers)
114
A device that measures the amount of light power transmitted on a fiber-optic line. Also called a fiber light meter.
OPM (optical power meter)
115
A device that measures the amount of light power transmitted on a fiber-optic line. Also called an OPM (optical power meter).
Fiber light meter
116
A cable used to connect a computer to the console port of a router.
Console cable
117
A modular interface that can be inserted in a switch to connect its motherboard with an external, fiber-optic cable.
Transceiver
