Networking+ Chapter 5

Multiplexing

A form of transmission that allows multiple signals to travel simultaneously over one medium.

A switch works as ...

A multiport repeater, as the bits transmitted "start over" at each port on the switch.

EMI (electromagnetic interference)

A type of interference that may be caused by motors, power lines, televisions, copiers, fluorescent lights, or other sources of electrical activity.

What is the minimum category of UTP cable required in order to support Gigabit speeds, also referred as the preferred category?

Cat 5e

Which categories of twisted-pair cable can support Gigabit Ethernet?

Cat 5e and higher

FEXT (far and crosstalk)

Crosstalk measured at the far end of the cable from the signal source

Alien crosstalk

Crosstalk that occurs between two cables

NEXT (near and crosstalk)

Crosstalk that occurs between wire pairs near the source of a signal

Noise that can degrade or distort a signal on a network is measured with what unit?

Decibels

Phone companies make use of what type of multiplexing in order to allow for phone services and DSL services over the same line?​

FDM

Which type of multiplexing is defined by frequency?​

FDM

Attenuation is the brief delay that takes place between the instant when data leaves the source and when it arrives at the destination

False

Because digital signals do not depend on amplitude or frequency differences to communicate information, they are more vulnerable to EMI noise.​

False

Bit rate is the measurement of bytes transmitted per second for throughput or bandwidth

False

Ethernet twisted-pair cabling usually contains 16 wires

False

Fast Ethernet has a maximum speed of 1000 Mbps

False

Fiber-optic cable has high throughput, high resistance to noise, spans long distances, and has poor security True or False

False

In order to achieve 1000Base-T over CAT5e cable, 2 pairs of copper are needed. True or False

False

Latency is the loss of a signal's strength as it travels toward its destination

False

Optical loss is the degradation of the light signal after it travels a certain distance away from its source. True or False

False

Shapes and polishes for SMF ferrules are the UPC, APC, and NPC True or False

False

Singleplexing is a form of transmission that allows multiple signals to travel simultaneously over one medium

False

The difference between continuity testers and performance testers lies in their sophistication and price. True or False

False

WDM (wide division multiplexing) uses a wide beam to allow more light pulses to travel on each fiber strand

False

With Fast Ethernet, the T568B standard requires the brown pair to transmit

False

MMF contains a core of 50 or 62.5 millimeters in diameter

False- It is 50 or 62.5 microns

What does ethernet twisted-pair contain?

Four wire pairs

A high ratio can result in what?

Greater attenuation

Throughput

The measure of how much data is actually transmitted during a given period of time.

The twist ratio is...

The number of twists per meter or foot in a twisted pair cable.

Jitter

The variability of latency over time across a network.

Latency

Time it takes for a bit to travel from its sender to its receiver.

When does a speed and duplex mismatch occur?

When you specify a particular speed and duplex that's not supported by the neighboring device

What is a multiplexer?

a device that can combine many signals on a channel

What will a repeater regenerate?

a digital signal in its original form without the noise it might have previously accumulated.

Common types of crosstalk:

1. Alien crosstalk 2. NEXT (near and crosstalk) 3. FEXT (far and crosstalk)

Two common sources of noise?

1. EMI (electromagnetic interference 2. Crosstalk

Three factors that can degrade network performance?

1. Noise 2. Attenuation 3. Latency

Two important NIC settings

1. The direction in which signals travel over the media 2. The number of signals that can traverse the media at any given time

Methods of communication

1. full-duplex or duplex 2. half-duplex 3. simplex

What is the maximum supported throughput of a CAT6 cable?

10 Gbps

What is the maximum speed of fast ethernet?

100 Mbps

What is the maximum speed of Gigabit Ethernet?

1000 Mbps

The 1000Base-LX utilizes light with what wavelength?

1300 nanometers

Standard PoE devices ​must be provided with how much power in order to function?

15.4 watts

Both 10GBase-ER and 10GBase-EW have what maximum distance limitation on a segment of single mode fiber?

40 KM

Coaxial cable specifications: RG-6

75 ohms, 18 AWG conducting core, usually made of straight copper.

Coaxial cable specifications: RG-59

75 ohms, 20 or 22 AWG core, usually made of braided copper.

PoE+ devices are defined by what IEEE standard? 802.3af or 802.3t

802.3at

Half Duplex

A type of transmission in which signals may travel in both directions over a medium, but in only one direction at a time.

How is duplexing achieved?

By pairing two wires together inside the cable, where one wire transmits and the other receives.

Which is the most common for multimode fiber?​

MT-RJ

Which part of a toner and probe kit emits a tone when it detects electrical activity on a wire pair?

Probe

Select the answer that is not a fundamental property of analog signals or select, "All choices are a fundamental property of analog signals." Amplitude Frequency Wavelength Pulse Length Phase

Pulse Length

Telephone connections follow what registered jack standard?

RJ 11

What is the most common way to measure latency?

RTT (round trip time)

​What term below is used to describe the outer-most layer of protective covering of a coaxial cable?

Sheath

You have been awarded a contract for wiring a new federal building. What twisted-pair wiring standard must you use? a. TIA/EIA 568F b. TIA/EIA rollover c. TIA/EIA 568A d. TIA/EIA 568B

TIA/EIA 568A

Bandwidth

The amount of data that could theoretically be transmitted during a given period of time

Why is SMF (Single Mode Fiber) more efficient over long distances than MMF (Multimode Fiber?

The core of SMF is much narrower than that of MMF, and reflects very little.

What can affect latency?

The length of the cable

RTT (round trip time)

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.

1000Base-SX is used for short runs, connecting a data center with a data closest

True

A Cat 6a standard can support a throughput of 10,000 Mbps for 100 meters

True

A continuity tester should not be used on a live network segment.

True

A transceiver is a modular interface that can be inserted into a switch interface to upgrade the interface, the switch must allow for changes and upgrades to its interface at any time

True

APC (Angle Polished Connector) ferrules create less back reflection than do UPC (Ultra Polished Connector) ferrules because the end faces are placed at an angle to each other, so the reflection is sent back in a different direction than the source of the signal.

True

Fiber-optic cable is the most expensive transmission medium.

True

Gigabit ethernet uses all 4 fours wire pairs for sending and receiving. True or false?

True

Jitter is caused by packets arriving out of order due to varying latency, also called PDV (packet delay variation), it causes streaming video to pause or jump around

True

Latency is measured by calculating a packet's RTT, or 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. True or False

True

Optical loss grows with every connection point in the fiber network.

True

PoE standard type of devices are the PSE and the PD

True

SMF accommodates the highest bandwidths and longest distances because it reflects very little so the light does not disperse as the signal travels along the fiber

True

TDM divides the channel into multiple intervals of time slots, times slots are reserved for designated nodes

True

The IEEE 802.3af standard specifies a method for supplying electrical power over twisted-pair ethernet connections

True

The difference between continuity testers and performance testers lies in their sophistication and price.

True

The distance a cable can carry light depends on the light's wavelength and whether it is single mode or multimode cable True or False

True

The longest SMF distance standard is 40,000 meters for 10GBase-ER True or False

True

To create a patch cable terminate the RJ-45 plugs at both ends of the cable using the same T568 standard at both ends

True

Two sources of pulsing lights used for fiber-optics are lasers and LEDs True or False

True

UTP is more popular than STP because it is cheaper and easier to install

True

Using Fast Ethernet, of the four wire pairs, one wire pair sends data and another wire pair receives data and the other two wire pairs are not used

True

Which cabling consists of one or more insulated wire pairs encased in a plastic sheath but not surrounded by a shielding made of a metallic substance?

UTP (Unshielded twisted pair)

F-connectors

attach to coaxial cable so that the pin in the center of the connector is the conducting core of the cable

What type of cross-talk occurs between wire pairs near the source of a signal? ​

near end cross talk

Crosstalk

occurs when the signals of one wire affect the signals on an adjacent wire or cable

What multiplexing technology lowers cost by spacing frequency bands wider apart to allow for cheaper transceiver equipment?

coarse wavelength division multiplexing

A repeater is used to

compensate for attenuation

Multiplexing is used by networks to?

increase the amount of data that can be transmitted in a given timespan over a given bandwidth

BNC connector

is crimped, compressed, or twisted onto a coaxial cable

You've been handed a fiber with a 1.25-mm ferrule that requires a connector. What is the most commonly used connector for this ferrule size?

local connector (LC)

Attenuation

loss of a signal's strength as it travels away from its source

full-duplex or duplex

signals are free to travel in both directions over a medium simultaneously

simplex

signals may travel in only one direction, and is sometimes called one way, or unidirectional, communication

Signals that can travel in only one direction on a medium are referred to as what type of signal?

simplex

Utilizing time slots that are adjusted according to priority and need is an example of what type of multiplexing on copper lines?

statistical time division multiplexing

Bit rate

the bit per second

The more twists per foot in a pair of wires... a. the faster the transmission is sent or received b. the greater the delay c. the more resistant the pair will be to crosstalk or noise.

the more resistant the pair will be to crosstalk or noise.