MISC 372 Ch.5

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Fiber that has a core diameter of 8 microns in

...

In this book, we use the terms "Ethernet" and "802.3" interchangeably

...

Light aggregation can increase trunk speed by a factor of

...

The ethernet length field gives the length of the

...

The longest transmission distances are possible with

...

The main benefit of parallel transmission over serial transmission is

...

What 802 Working Group creates Ethernet standards

...

Which light wavelength dominates in LANs

...

CAT 5e and CAT 6 wiring can carry Ethernet 100 meters up to

1 Gbps

What type of copper wiring is widely used in Ethernet?

4-pair UTP

How many wires are there in a UTP Ethernet cord

8

Which working group is likely to develop security standards to be used by multiple LAN/WAN technologies

802.1

ARP cache poisoning can be defeated using ________.

802.1AE

The ________ standard was created to prevent attackers from walking in and simply plugging a computer into a wall jack and therefore accessing the network

802.1X

In digital signaling there is (are) ___ state(s)

A small number of

Which UTP quality levels can send signals at 10Gbps

Both Category 6 and Category 6A

The Ethernet data field contains

Both a packet and the LLC subheader

Which UTP quality levels can send signals at 10Gbps for 100 meters

Category 6A

The official name for Ethernet addresses is the ___ addresses

EUI-48

UTP

Ethernet LANS typically use this wiring to connect users to the nearest switch, at two ends wires are placed within an RJ-45 connector

What organization creates Ethernet standards?

IEEE

multimode fiber

LANs use this, which is relatively thick core, light rays can enter over a wide range of angles, quality is measured by modal bandwidth in MHZ.km

Ethernet's hierarchical topology tends to create

Lower cost per frame handled

Ethernet addresses were formerly called

MAC

Ethernet has only a single standard at the ___ layer

MAC

Which of the following is used most heavily in LANs for fiber transmission links

Multimode fiber

Ethernet's hierarchical topology makes it ________

Neither expensive nor reliable. CHEAP

sadipscing elitr, sed diam

None of these

What is the maximum power for POE Plus in the standard?

Not "75 watts"

Which of the following is a benefit of using a central authentication server?

Not "consistency in authentication"

Strong security is needed to

Not "reduce total cost"

Link aggregation can increase trunk speed by a factor of ________.

Not "two" not "neither two nor three"

___ fiber is being sold today

OM4

4-pair UTP terminates in a(n) ___ connector

RJ-45

In LANs, ___ typically is for ___

UTP, access lines

Ethernet can offer ___ priority levels

Up to 8

Frequency, wavelength, and amplitude.

What are the three characteristics of light waves?

signal

a disturbance that propagates down a transmission medium to the receiver, which reads the signals

modal dispersion

a limiting factor for distance in multimode fiber

category (cat)

a measure of UTP quality

An Ethernet switch knows

a single port number for each EUI-48 address

local loop

access link between the customer premises and the nearest telephone company switch (called the end office switch)

noise spikes

always cause some errors and cause more errors as the SNR decreases and the Number of errors become unacceptable well before the signal reaches the noise floor

single-mode fiber

are used by carrier and limited by absorptive attenuation; carry signals much farther than multimode fiber

full‐duplex transmission

attenuationThe ability to transmit in both directions simultaneously for optical fiber cord

In 802.1X, the workgroup switch is the ________.

authenticator

Which of the following is relatively immune to small errors

binary signaling

head end

cable television operator has a central distribution point

DSL access multiplexer (DSLAM)

carrier needs to install this device to separate voice and data traffic, links voice to PSTN and link data to data network

access lines

connect hosts to the nearest switch; dominant for UTP

trunk lines

connect switches to other switches; mostly optical fiber

In optical fiber, light travels through the

core

What type of switch connects switches to other switches

core switches

two- way amplifiers

could carry data in both directions; allowed cable to compete in broadband service

longer propagation distances

create attenuation that results in lower SNR and therefore more noise errors

terminal crosstalk interference

crosstalk interference at the ends of the UTP cord, usually is much larger than the rest of crosstalk interference over the entire rest of the cord, therefore must not untwist UTP wires more than 1.25 cm when adding connectors to limit intereference, among 3 this one is the threat

The purpose of LLC subheader is to

designate the type of packet in the data field

Creating effective backup links in RSTP is

difficult and time consuming

What form of transmission is most resistant to transmission errors

digital

twisting each pair's wires

dramatically reduce interference, limiting to an acceptable level

If an Ethernet receiver detects an error in an arriving frame, it

drops the frame

Optical fiber cords use two strands

for full-duplex transmission

parallel transmission

for gigabit Ethernet, sending data simultaneously on two or more transmission lines in the same direction, speed is benefit.

The ability to transmit in two direction simultaneously is

full-duplex communication

Optical fiber's main advantage of UTP is

greater distance span

Switches in an Ethernet LAN are organized in a ___ topology

hierarchical

tempor

hierarchical

hertz (Hz)

how frequency is measured, one of these is =one cycle per second

nanometers (nm)

how wavelengths are measured, one billionth of a meter

signal to noise ratio (SNR)

if a signal is far larger than the noise floor then we have a high? , that means a a few random noise spikes will be large enough to cause errors

serial transmission

if one pair of wires is used to send a transmission, this is ? because the transmitted bits must follow one another in series, for slower Ethernet that run at 10 to 100 mbps

Ethernet is inexpensive thanks to

its hierarchical topology

optical fiber transmission

laser light is reported in wavelengths

frequency

light waves which is the number of times the wave goes through a complete cycle per second

UTP propagation distance

limit to 100 meters at all speeds up to 1 Gbps, the signal still will be comfortably larger than noise floor when it arrives at receiver so there will be few noise errors

2- pair data-grade UTP

local loop uses this technology; data grade meaning carriyny data instead of voice

Ethernet becomes the dominant of LAN technology primarily because of its

low cost, compared with competing technologies

When the light energies of two pulses arrive at overlapping times, this is

modal dispersion

noise spikes

much higher or lower than the noise floor

Modal dispersion limits transmission distance in

multimode fiber

crosstalk interference

mutual interference among wire pairs in a UTP cord or between wire pairs in a cord

perfect internal reflection

no light escapes into the cladding or beyond

optical fiber

normally used to carry signals farther, not faster

A local area network operates

on a customer premises

At what layer is the 100BASE-TX standard

physical

Ethernet standards are specified at the ___ layer

physical and data link

Ethernet usually has a 100 meter distance limit for

physical links

provisioning

providing service

UTP categories rate the ___ of UTP cabling

quality

noise

random electromagnetic energy;receiver actually gets the total of the signal plus the noise, UNWANTED, WITHIN PROPAGATION MEDIUM

Managed Ethernet switches ________

reduce hardware costs

asymmetric DSL (ADSL)

residential service with much higher download to the home speeds than upload speeds.

transceiver

sender/receiver

attenuated

signal has weakened; received signal differs from the transmitted, too much= receiver will not recognize it

distorted

signal's shape has been changed

Physical layer standards govern

signaling

amplitude

strength of the wave, measured as power

cladding

surrounding the core is a thicker glass cylinder, 125 microns in diameter,reflects the signal back into the core with perfect internal reflection so that no light escapes from the core.

Using priority in Ethernet requires the use of ___ fields

tag

Untwisting wire pairs no more than 1.25cm at the ends reduces

terminal crosstalk interference

drop cable

the access line to individual homes is a thin coaxial cable and the resident connects it to their TV

propagation effects

the changes in the signal during propagation; if this is too large, the receiver will not be able to interpret the signal correctly

wavelength

the distance between comparable parts on two successive cycles-peak to peak, trough to trough. In optical fiber transmission, laser light is reported as this?

noise floor

the mean of the noise energy

fiber to home (FTTH)

to provide extremely high speeds to homes by running carrier-grade fiber from the end office switch to residential households

core

to send signals by injecting light into a very thin glass rod and are 8.3, 50, or 62.5 microns

splitter

to use DSL service effectively, user must plug a ? into each telephone jack

propagates

travelling of a signal down a transmission medium

In LANs, optical fiber typically is used in

trunk lines

In binary signaling the is (are) ___ state(s)

two

electromagnetic interference (EMI) or inteference

unwanted external electromagnetic energy coming from electrical motors, fluorescent lights, and even other nearby UTP cords. will also add to the signal energy and make signal unreadable

Which of the following can increase reliability considerable in an Ethernet LAN

using the Rapid Spanning Tree Protocol

The distance between two corresponding points in adjacent cycles is the

wavelength

digital subscriber line (DSL)

whenever data is transmitted over 1-pair voice-grade UTP. The subscriber line is the line already running to the residential premise

Under the standard, Ethernet switches can provide enough power over UTP for ________

wireless access points

What type of switch connects users to the network

workgroup switches


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