802 Layer 2

Question 1

____ allows multiple users access to the same medium

____ uses collision avoidance to minimize data loss in transmissions

Answer 1

Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA)

Question 2

• each user is assigned a code to identify its data

Answer 2

CDMA Code Division Multiple Access

Question 3

• each user gets a specific time slot to send data

Answer 3

TDMA - Time Division Multiple Access

Question 4

used in ethernet connections between devices

Answer 4

CSMA/CD - Carrier Sense Multiple Access with Collision Detection

Question 5

used in 802.11 wireless LANs

Answer 5

CSMA/CA - Carrier Sense Multiple Access with Collision Avoidance

Question 6

Listening to ensure the channel is idle, it will send its data, then wait for a response from the destination device with an acknowledgment If the acknowledgment is NOT received it will send the data again.

Answer 6

Collision Avoidance (CA) protocol

Question 7

sending a REQUEST-TO-SEND message, an access point will respond with a CLEAR-TO-SEND message

Answer 7

RTS/CTS

Question 8

Device scans (passive OR active) for SSID to use

APs transmit beacon frames

Answer 8

Step 1 : Discovery

Question 9

response from the AP/router with a success or failure message.

request is sent from the mobile device that contains the station ID

Answer 9

Open system

Question 10

requests “shared key”

AP sends challenge phrase

Station encrypts challenge phrase

AP decrypts and verifies original text

Answer 10

Shared Key Authentication : Wired Equivalent Privacy (WEP)

Question 11

There are three frame types:

Answer 11

Management

Control Frames

Data

Question 12

constantly broadcasted signal from a WAP announcing itself to clients, and broadcasts its parameters (SSID, Supported data rate, RF channel number used, etc)

Answer 12

Beacon

Question 13

Used by clients to obtain information from an AP. This can be directed to a SSID or to any AP available (null probe request), happens constantly with clients

Answer 13

Probe Request

Question 14

Used by AP to send info about its parameters (same info found in Beacon)

Answer 14

Probe Response

Question 15

used in the process to gain access to a network

Answer 15

Authentication

Question 16

once authenticated, a client can request association to an SSID

Answer 16

Association Request

Question 17

sent by an AP to accept or deny association

Answer 17

Association Response

Question 18

actual data being sent

Answer 18

Data

Question 19

used to prioritize data ie-streaming data

Answer 19

QoS Data

Question 20

used by client to inform an AP of a change in clients status/power save mode

Answer 20

Null Data

Question 21

Wireless capability gives us the ability to convert 1s and 0s into radio waves, and convert radio waves back into 1s and 0s. (T/F)

Answer 21

True

Question 22

CSMA/CA is a protocol that operates in which layer of the OSI model?

Answer 22

Layer 2- Data Link Layer

Question 23

Which technologies, which allow multiple users to send data across a shared medium, do not use Collision Detection or Collision Avoidance?

Answer 23

CDMA

TDMA

Question 24

Wireless networks often use a Collision Avoidance (CA) protocol. Where a device will wait a random amount of time, before attempting to send data again, if it recognizes the medium as being busy.

Answer 24

True

Question 25

What does RTS/CTS stand for?

Answer 25

REQUEST TO SEND/CLEAR TO SEND

Question 26

When a device first turns on, it must attempt to connect to a what?

Answer 26

Access Point

Question 27

Open System and Shared Key are two link-level types of authentication defined by IEEE 802.11 standards. (T/F)

Answer 27

True

Question 28

Open System Authentication consists of two communications:

Answer 28

Authentication Request/Authentication Response

Question 29

During the Shared Key Authentication Phase, the Access Point sends the challenge phrase back in encrypted text. (T/F)

Answer 29

False

Question 30

During the Shared Key Authentication Phase, the Station sends back to the AP the challenge phrase in clear text.

Answer 30

False

Question 31

WPA/WPA2 complies with the wireless security standard and strongly increases the level of data protection and access control (authentication) for a wireless network. (T/F)

Answer 31

True

Question 32

Association only occurs on wireless infrastructure networks, not in peer-peer mode.

Answer 32

True

Question 33

A station can associate with multiple AP/routers at one time.

Answer 33

False