Tag Archives: CCNA Wireless

CCNA Wireless Chapter 3, 4 and 5 Exam Answers

1.Wavelength can be described as…
The distance between successive crests of a wave

2.What is the wavelength of AM radio waves?
400-500M

3.What is the wavelength of satellite waves?
1MM

4.As frequency increases, distance travelled
Decreases

5. 1mhz is 1 million cycles per second

6. 1ghz is 1 billion cycles per second

7. Gain provided by antennae helps to cancel out ___________ from cabling
Loss

8.The EIRP calculation is…
EIRP = transmitter O/P power – cable loss + antenna gain

9.Free path loss is a result of attenuation and not interference

10. As amplitude increases range increases

11.Reduction of amplitude is aka absorption

12.Absorption creates heat

13.The main issue presented by reflection is Multi path interference

14.What is multipath interference?
When two copies of the same signal arrive out of phase with eachother, and weaken or cancel eachother out

15.What is scattering
When a signal is reflected by objects which are reflective but have jagged edges

16.What is refraction
The changing or bending of a wave as it passes through something of a different density

17.Dryness refracts signals away from earth

18.Humidity refracts signals towards earth

19.RSSI is received signal strength indicator

20.A potential replacement for RSSI is receive channel power indicator

21.What is SNR?
Signal to noise ratio, how much stronger a received signal is than the underlying noise, it is measured in dB

22.What is link budget?
Value which accounts for gains/losses between tx and rx

23.What is the link budget equation?
Received power (dBm) = (tx power + gains – losses)

24.3 types of polarization for antennae are:
1) Vertical
2) Horizontal
3) Circular

25.In an electromagnetic field, the magnetic field is perpendicular  to the electric field

26.Cisco antennae all have vertical polarization

27.What is diversity?
The use of two antennae for each radio to increase the odds of a better signal

28.What has to be the same about each antennae in a diversity scenario?
Their orientation

29.Diversity is used to fight…
Multi path interference issues

30. 2 main types of antennae are
1) Directional
2) Omnidirectional

31. The h-plane of an antenna is aka
The azimuth

32.The e-plane shows how a signal would propagate vertically

33.The 2.2 dBi dipole antenna is aka the rubber ducky antenna

34.The loss incurred by a cable is usually referred to as the cable loss specification

35.3 types of antenna connectors are…
1) RP-TNC
2) N-connector
3) SMA (2 types)

36.2 subtypes of SMA connectors are
RP-SMA and SMA-RS

37.Attenuators reduce signal

38.Amplifiers add active gain to compensate for cable loss

39.Active gain means gain is added without focus change

40.What shunts lightning surges before they reach the wired LAN lightning arrestors

41.Do lightning arrestors protected against direct strikes?
no

42.What are used to send a signal in two different directions?
Splitters

43.The range of a WPAN would be..
<5-10m, or 20 feet

44.WPAN’s use the 2.4ghz spectrum

45.Bluetooth is an example of a WPAN

46.Bluetooth uses what for an emission method
FHSS

47.Generally, clients in a WLAN are _______ or less from the access point
100m

48.An example of a WMAN is WiMAX

49.WiMAX could possibly replace T1 AND T3 technologies

50.Is it ideal for a WMAN to use ISM frequencies?
no

51.Do WWAN’s have high data rates?
no

52.The most popular versions of WWAN’s are… (2)
1) GSM
2) CDMA

53.Two original versions of 802.11 topologies:
1) Ad-hoc, no central point
2) Infrastructure, has a central point

54.The coverage area of an AP is called the
BSA

55.The wired network is aka the…
Distribution system

56.2 or more BSA’s make an…
ESA

57.The process of clients moving AP’s called…
Roaming

58.An SSID is a combination of what two things
MAC address and network name

59.AP’s can have up to __ SSID’s
16

60.An AP offering more than one NW called a
MBSSID

61.What is an AWGB
Connects to upstream AP’s and allows wired ethernet clients to connect as non-standard clients

62.What is an UWGB
Allows single wired device to be bridged upstream to an AP as a standard device

63.Overlap needed for a wireless repeater is…
50%

64.Original AP in a repeated wireless network is called…
The root device

65.Outdoor wireless bridges operate at what layer of the OSI model
L2

66.What is used to determine the best path in a wireless mesh network?
AWPP protocol

CCNA Wireless Chapter 1 and Chapter 2 Exam Answers

1.With radio frequencies, the goal is…
to send as much data as possible
as far as possible
as fast as possible

2.The IEEE wireless standard is…
802.11

3.The FCC defines (4 things)
Unlicensed frequencies
Power @ which frequencies can be transmitted at
Transmission technologies which can be used
Locations WLAN dev’s can be deployed

4.The European equivalent of the FCC is called
ETSI: European Telecommunications Standards Institute

5.To achieve bandwidth from RF, an _____________ method is needed, for example ______________
emission method
example: spread spectrum

6.To place data on RF signals, a __________ method is required
modulation method

7.Modulation is…
The addition of data to a carrier signal

8.As data is placed on a signal, more ______________ aka _________________ is used
frequency spectrum or bandwidth

9.In wireless terminology, bandwidth refers to…
The width of the RF channel

10.Hertz can be described as…
Cycles /second

11.Extremely low frequency range = 3-30hz

12.Super low frequency range = 30-300hz

13.Ultra low frequency range = 300hz-3khz

14.Very low frequency range = 3khz-30khz

15.Low frequency range = 30khz-300khz

16.Medium frequency range = 300khz-3mhz

17.High frequency range = 3mhz-30mhz

18.Very high frequency range = 30mhz-300mhz

19.Ultra high frequency range = 300mhz-3ghz

20.Super high frequency range = 3ghz-30ghz

21.Extremely high frequency range = 30ghz-300ghz

22.The 900mhz band’s range is 902mhz-928mhz

23.The 2.4ghz band is used by which 3 wireless standards?
802.11b,g, and n

24.The 2.4ghz band’s range is
2.400ghz – 2.4835ghz

25.The 2.4ghz band has ____ channels
11

26.The 2.4ghz band’s channels are _____ wide
22mhz

27.Which channels in the 2.4ghz range do not overlap?
1, 6 and 11

28.The 2.4ghz band uses _______ modulation
DSSS: direct sequence spread spectrum modulation

29.What standards use the 5ghz band?
802.11a and n

30.The data rate range of 802.11a is
6-54mbps

31.In the 5ghz band, channels are _____ wide
20mhz

32.The 5ghz band has _______ channels
23

33.The 5ghz band uses _________ modulation
OFDM

34.The data rates available inside the 5ghz band are:
6,9,12,18,24,36,48 and 54mbps

35.Define modulation:
Varying in a signal or a tone called a carrier signal

36.Define encoding:
When data is added to that signal

37.A modulated waveform consists of 3 parts
1) amplitude; strength of signal
2) phase; the timing of signal between peaks
3) frequency; how often signal repeats /sec

38.In DSSS, the transmitted signal is spread
across the entire channel

39.Every data bit in DSSS is sent as a
chip stream

40.How many bits need to change in a chip stream before the bit is miscommunicated
5 or more

41.802.11 1 & 2 mbps use which encoding method?
barker code

42.802.11 5.5 and 11mbps use which encoding method?
cck: complimentary code keying

43.How many key words does cck have?
64

44.Each key word in cck communicates how many bits?
up to 6

45.802.11b uses DBPSK and DQPSK modulation, what are these?
These are methods of representing information by changing the phase of the signal

46.What is DBPSK?
Two phases are separated by 180 degrees, DBPSK modulates 1 bit per symbol

47.In DBPSK, a 180 degree phase shift = 1

48.In DBPSK, a zero degree phase shift = 0

49.Is OFDM considered a spread spectrum technology?
no

50.Channels in OFDM are divided into 20mhz, each subcarrier within these channels is 312.5hz wide

51.MIMO is used by
802.11n

52.As distance from AP increases, data rates
decrease

53.What is DRS?
Dynamic rate shifting
The data rate can be dynamically shifted without the connection being dropped

54.CSMA/CD uses a ___________ field to tell other transmitters how long it needs the channel for
duration field

55.The FCC is the federal communications commission

56.Cisco antennae use the __________ connector which stands for
RP-TNC (reverse polarity thread neil concelman connector)

57.What is the measurement for the power emitted by an antenna?
EIRP: effective isotropic radiated power

58.P2MP rules:
36dbm EIRP max
30dbm transmitter power
6db gain of antenna and cable combined
A 1:1 ratio of power to gain