Chapter 7, Flashcards Preview

CWNA > Chapter 7, > Flashcards

Flashcards in Chapter 7, Deck (37):
1

What is a station?

The wireless client.

2

What are service sets?

Describes how radios may be used to communicate with each other.

3

What is a simplex transmission and provide an example?

A simplex communication, one device is capable of only transmitting, and the other device can only receive.

FM radio is a good example.

4

What is a thin access point?

With thin access points, the AP configuration and intelligence resides inside a WLAN controller

5

Managed wired switches maintain dynamic MAC address tables known as what?

CAM tables.

6

What is a CAM table?

Tables that can direct frames to ports based on the destination MAC address of a frame.

7

What does it mean when a station is associated?

Have layer 2 connection with an access point.

8

What is the MSDU?

The payload of a wireless 802.11 data frame is the layer 3–7 information.

9

Define what the 802.11-2012 integration service (IS) integration is? Why is it important?

This describes the delivery and transfer of MSDU's between the RF medium and the 802.3 wired network.

This is important Because the wired infrastructure is a different physical medium, an 802.11 data frame payload must be effectively transferred into an 802.3 Ethernet frame.

10

Give an example of an integration service using a VoWiFi phone.

A VoWiFi phone sends an 802.11 data frame to a standalone access point. The MSDU payload of the frame is a VoIP packet with a final destination of an IP PBX that resides at the 802.3 network core. The integration service removed the 802.11 header and trailer and then encases the MSDU VoIP payload inside an 802.3 frame. Reverse is done.

11

What is a distribution System Medium? Give an example.

A logical physical medium used to connect access points. The most common example is an 802.3 medium.

12

What is a distribution System Service? What does this service do in junction with the Integration Service?

System services built inside an access point are usually in the form of software. The DSS provide the switch like intelligence. These software services are used to manage client station associates, associations, and dissociations.

This works in tandem with the integration service because Distribution system services because it
also use the layer 2 addressing of the 802.11 MAC header to eventually forward the layer
3–7 information (MSDU) either to the integration service or to another wireless client station.

13

What is a wireless distribution system? Give 2 examples.

This is the same as a distribution system medium on 802.3 however this time its the wireless network.
An example would be a mesh network.
Another example would be a wireless repeater.

14

What are the 4 MAC addresses that are used in a frame when a wireless distributed network is used?

a frame sent within any type of WDS requires four MAC addresses: a source address, a destination address, a transmitter address, and a receiver address.

15

Do wireless repeaters and the AP have to be on the same channel?

Yes, because it effectively increases the cell.

16

What is an SSID?

It is a logical name used to identify an 802.11 wireless network. It is also used for AP's to identify each other.

17

How many characters can an SSID have? Is it case sensitive?

32 characters and yes it is case sensitive,

18

What is a basic service set?

Consist of one AP radio with one or more client
stations.

19

What is a BSSID?

The layer 2 identifier of each individual BSS. The radio's MAC address. Most often the BSSID is the
MAC address of the radio network interface.

20

Name 3 purposes for the BSSID

1. The BSSID address plays a role in directing 802.11 traffic within the basic service set.
2. This address is also used as a unique layer 2 identifier of the basic service set.
3. Furthermore, the BSSID address is needed during the roaming process.

21

What is a basic service area? How does RSSI come into play with this?

The physical area of coverage provided by an access point in a BSS.

Client stations can move throughout
the coverage area and maintain communications with the AP as long as the received signal strength between the radios remains above received signal strength indicator (RSSI) thresholds.

22

What is an extended service set?

An extended service set is two or more basic service sets connected by a distribution system medium. Usually an
extended service set is a collection of multiple access points and their associated client
stations, all united by a single DSM.

23

What is nomadic roaming?

When a client leaves a BSS that isn't overlapping with another BSS. The client loses connectivity, That small window of time that occurs between the client moving between BSS is called nomadic roaming.

24

What is colocation?

When a BSS overlaps heavily with another BSS on a different channel. This is designed to provide capacity.

25

What is an independent basic service set? Explain in detail.

The radios that make up an IBSS network consist solely of client stations (STAs), and no access point is deployed. All of the stations transmit frames to each other directly and do not route their frames from one client to another. All client station frame exchanges in an IBSS are peer to peer. All stations in an IBSS must contend for the half-duplex medium, and at any given time
only one STA can be transmitting.

26

What is a mesh basic service set?

Set of APs that provide mesh distribution.

27

What is a mesh point portal, or MPP?

one or more mesh APs that are typically connected to the wired infrastructure.

28

What are mesh points?

Mesh APs that are not connected to a wired infrastructure.

29

What is a hybrid wireless mesh protocol ?

Because routing on an AP mesh network is all layer 2 routing using radio MAC addresses, all mesh networks have to have at least one mesh AP connect to an 802.3 network. The mesh protocol is a routing protocol designed for mesh networks that allow mesh points to decide the best route for forwarded frames to take.

30

What does it mean when an AP is in root mode?

The main purpose of an AP is to serve as a portal to a distribution system. The normal default
setting of an AP is root mode, which allows the AP to transfer data back and forth between
the DS and the 802.11 wireless medium.

31

What are 2 other common terms that vendors use for root mode?

Access Mode and AP mode.

32

What does it mean when an AP is in bridge mode?

The AP radio is converted into a wireless bridge. This typically adds extra MAC-layer intelligence to the device and gives the AP the capability to learn and maintain tables about MAC addresses from the wired side of the network.

33

What does it mean when an AP is in workgroup bridge mode?

The AP radio is transformed into a workgroup bridge which provides wireless backhaul for connected 802.3 wired clients.

34

What does it mean when an AP is in repeater mode?

The AP radio performs as a repeater AP which extends the coverage area of a portal AP on the same channel.

35

What does it mean when an AP is in Mesh Mode?

The AP radio operates as a wireless backhaul radio for a mesh environment. Depending on the vendor, the backhaul radio may also allow for client access.

36

What does it mean when an AP is in scanner mode?

The AP radio is converted into a sensor radio, allowing the AP to integrate into a wireless intrusion detection system (WIDS) architecture. An AP in scanner mode is in a continuous listening state while hopping between multiple channels. Scanner mode is also often referred to as monitor mode.

37

What does it mean when an AP is in infrastructure mode?

When running in Infrastructure mode, the client station will allow communication via an access point. Infrastructure mode allows for a client station to participate in a basic service set or an extended service set. Clients that are configured in this mode may communicate, via the AP, with other wireless client stations within a BSS