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Comptia > A+ 1001: wireless > Flashcards

A+ 1001: wireless Flashcards

1
Q

IEEE 802.11

A

Primary standard for wireless communication

Two modes:

  • infrastructure mode
  • adhoc mode

Based on ISM ( Unlicenced industrial, scientific, and medical radios bands)
- 2.4 GHz and 5 GHz band

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2
Q

WAP

A

Wireless Access Point

Bridges 802.11 and ethernet networks

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3
Q

Infrastructure mode

A

uses a wap and network card connection

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4
Q

Wireless Network Card

A

Manages Network activity on a device

connects to a SSID that is configured on a WAP

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5
Q

Where is the antenna for the wireless card in laptops and mobile devices

A

Usually, it is inside the monitor itself

For phones and tabs it is in the case itself

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6
Q

SSID

A

Service Set Identifier

WAPs are configured with SSID

The network/connection name that appears on devices when look for a connection

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7
Q

Adhoc mode

A

no WAP, only network cards connecting to one another

Used to connect computer together wirelessly

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8
Q

Antenna

A

3 Types

  1. Omni-directional: Radiates signal in all directions like a ball
  2. Dipole: Two omnidirectional antennas pointing in opposite direction: Radiates signal in a big flat donut like circle
  3. Patch: Looks flat. Radiates signal as the half-a ball
  4. Yagi: Highly directional. The radiation pattern looks like a football. Good for sending signals long distances
  5. Parabolic: Looks like a dish. Used for long-distance throws
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9
Q

802.11 extensions

A
  1. 11a : 54 Mbps 5Ghsz (wifi 1)
  2. 11b : 11 Mbps 2.4Ghsz (wifi 2)
  3. 11g: 54 Mbps 2.4Ghsz (wifi 3)
  4. 11n: 100Mbps 2.4/5Ghsz (MIMO) (wifi 4)
  5. 11ac (multi-user MIMO) (wifi 5)

b and g are backward compatible

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10
Q

What is a band?

A

A range of radio frequencies.

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11
Q

2.4 GHZ band range and channels

A

2.412 - 2.4884 Ghz

Japan 14 channels
Europe: 13 channels
US: 11 channels

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12
Q

5 GHz Band range and channels

A

5.150 - 5.875 GHz

Channels: (no odd numbers)
36, 40, 44,48,52,58,60,64

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13
Q

MIMO

A

multiple in/ multiple out

Allows a WAP to use multiple antennas to change it’s radiation signal pattern to zero in on a device

MIMO requires 802.11n

MU-MIMO can zoom in on multiple users at a time.

MU-MIMO requries 802.11ac

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14
Q

What should you do before plugging in a WAP or Router

A

Do an area survey to see wireless connections already in the same area and to see how congested the channels are

This is important when setting up 2.4 GHz channels as these are usually set manually

The 5GHz channels will configure itself

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15
Q

Maximum broadcast power that ISM allows

A

1 watt

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16
Q

Sight Survey

A

shows available channels in an ISM band

17
Q

What happens when we click on “remember this

A
17
Q

What happens when we click on “automatically connect to this network”

A

It creates a profile

profiles can be accessed in Settings > Netowrk & Internet > wifi > Mange known networks,

18
Q

Troubleshooting: Cannot connect to wifi network that you’ve connected to in the past

A
  1. Remove the profile by right-clicking on network and selecting “forget”
  2. Login again
19
Q

Troubleshooting: cannot connect to an SSID

A
  1. NIC is configured as DHCP client (APIPA)
  2. Passwords have changed
  3. SSID has changed
  4. Low RF Signal (turns on and off)
  5. NIC has static IP
20
Q

WMN

A

Wireless Mesh network

one base station, with SSID that connects to the network

With other stations (beacons/satelite) that connects to base station

Often used in small office or home offices

Has it’s own encryption

21
Q

RFID

A

Radio Frequency Identification

RFID tags are little radios that are activated and energised by reader

22
Q

NFC

A

Near Field Communication

It’s RFID

Used for Tap to Pay, or Tap to Print

23
Q

Bluetooth

A

Connects two devices together in a PAN (personal area network)

3 Classes

  1. 100mW 100M
  2. 2.5 mW 10m
    3 1 mW 1m
24
Q

Troubleshoot: Low RF Signal

A
  1. Too far from access point. Move closer to the router
  2. Antennas are not set up properly. Move antennas
  3. The access point’s signal is weak, boost Signal Strength
  4. SSID is not broadcasting (need to configure a profile)
25
Q

Troubleshoot: Limited Connectivity

A

Slow transfer speeds

  1. Radio signal interference (microwaves, radios etc), -> Remove interference
  2. Low RF signal
26
Q

Trouble Shooting: Intermittent connectivity

A

Connection interruptions

  1. Low RF signals, Modern routers will often restart
  2. Too many connections on network (increase the amount of waps, or configure QOS)
27
Q

Which is not a Wi-Fi capable device?

a. ) WAP
b. ) Switch
c. ) Smartphone
d. ) Tablet

A

b.) Switch

A switch is a hard-wired network device. WAPs, smartphones, and tablets are all Wi-Fi capable.

28
Q

Which 802.11 standard runs on 5GHz

a. ) 802.11a
b. ) 802.11b
c. ) 802.11c
d. ) 802.11g

A

a. ) 802.11a

802. 11a runs on 5GHz. 802.11b and 802.11g run on 2.4GHz. 802.11c is not a Wi-Fi standard.

29
Q

Which should you try first if your device can’t connect to a remembered public wireless network?

A

Delete the profile and try to connect again.

30
Q

Which is not true of wireless mesh networks?

a. ) Mesh networks have a single base station
b. ) Mesh networks are best for large enterprise networks
c. ) Mesh networks have one or more beacon/satellite stations
d. ) Mesh networks provide wide coverage in homes and small offices

A

b.)Mesh networks are best for large enterprise networks

Mesh networks don’t provide the customized configuration required for enterprise-sized networks. All of the other statements are true of wireless mesh networks.

31
Q

Which is not a wireless radio technology found in computers, tablets, or phones?

a. ) infrared
b. ) Bluetooth
c. ) RFID
d. ) NFC

A

a.) infrared

Infrared is a rarely-used wireless technology that communicates with infrared light, not radio waves. Bluetooth, RFID and NFC are all wireless radio technologies.

32
Q

Which is most likely to prevent a device from connecting to a previously-used Wi-Fi network?

a. ) The antenna/s are poorly orientated
b. ) The SSID has changed
c. ) Too many devices are accessing the WAP
d. ) The WAP is disconnected from the internet

A

b.) The SSID as changed

The most likely answer is that the SSID changed. Poor antenna orientation may reduce speed or range. Too many devices using the WAP are likely to cause low or intermittent connectivity. Even if a WAP is disconnected from the Internet, devices can still connect to it.

Comptia (24 decks)

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