Tag Archives: CCNA Wireless answers 2014

CCNA Wireless Chapter 12, 13 and 14 Exam Answers

Mobility is not synonymous with hot spot connectivity , rather it means a client can move between APs while keeping its IP address

The two types of client mobility are…
1) L2 mobility – client roams AP’s in same subnet
2) L3 mobility – client roams to AP in different subnet

What is a mobility group?
A group of WLC’s which share information with eachother

What is the maximum amount of WLC’s allowed in a mobility group?
24

What are the four requirements when creating mobility groups?
1) IP connectivity between WLC’s
2) Same workgroup name
3) Same virtual interface IP (ex. 1.1.1.1 in labs)
4) The MAC and IP of every other device in the group

What is a mobility domain?
The scope of communication between WLC’s in a WLAN

Mobility groups can be used to isolate roaming between different VLAN’s

Can clients roam between mobility domains?
No

What 4 things are required when a client is roaming between controllers?
1) Same mobility domain
2) Same revision of code
3) All AP’s need to have same SSID’s available
4) Again, virtual interface IP has to be the same

What is a simple way to describe intra-controller roaming?
New AP, same WLC

In intra-controller roaming, when is the client entry made in the database?
After the first AP association

What exactly is PKC?
Proactive key caching, it creates faster roaming times for 802.11i clients

What is a simple way to describe inter-controller roaming?
A client roams between two different WLC’s

What is the basic 4 step process of a client performing inter-controller roaming?
1) The client roams from WLC1 to WLC2
2) WLC2 makes a mobility announcement in order to find the WLC that has the client’s MAC (which is WLC1)
3) WLC1 responds to this announcement, handshakes and ack’s
4) This process moves the client DB entry to WLC2

How is L3 roaming accomplished?
Through a process called EoIP (ethernet over IP).
It is a tunnel created between controllers.
Original controller called “anchor”, the new controller is called the “foreign”

What are the two types of L3 roaming?
1) Symmetric
2) Asymmetric

The 3 primary components of WLC configuration are:
1) WLAN – the SSID and its corresponding parameters
2) Interface – virt. conn. to IP stack
3) Port – phys. connection to wired LAN

Two types of interface on a WLC are:
1) Static
2) Dynamic

Out of the two types of interfaces on a WLC, which one is created by the WLC and which one is created by an administrator?
Static: WLC
Dynamic: Administrator

Describe the management interface:
For in-band management
Used to communicate with other NW devs.
Also used by LAP in discovery phase

Describe the AP manager interface:
This is how the WLC communicates with LAP’s

Describe the virtual interface:
Used by WLC to terminate VPN’s from LAP’s, for DHCP relay connections, mobility management etc

What is special about the virtual interface?
It should not have a routable IP

Describe the service port:
For out-of-band management

What is special about the service port?
No trunking support

Describe the role of dynamic interfaces:
They link SSID’s to VLAN’s

What is the maximum amount of dynamic interfaces allowed on a WLC?
512

What 4 roles can an AP fulfill?
1) AP
2) Repeater
3) WG bridge
4) Scanner

3 things required for converting an autonomous AP to an LWAPP LAP are:
1) Upgrade tool
2) IPSU tool
3) LAP IOS image

What version does the LAP IOS image have to be?
12.3 (7) JA or above

What does the text file contain which is used to upgrade the IOS for LAP purposes?
1) IP of AP
2) Username/PW for telnet auth
3) Enable mode PW

What IP is used for TFTP servers pushing out autonomous AP IOS images?
It must be on the 10.0.0.0 /24 NW

CCNA Wireless Chapter 9 Exam Answers

In a wireless model, frames generally go from a lightweight AP to a WLC

A WLC is…
A WiLAN controller

Active scanning is…
When a client sends probes out

Passive scanning is..
When a client waits for beacons

What comes first, the auth request or the assoc request frame when a client attempts to connect to an AP?
The auth request comes first

Briefly count off the steps for wireless association to an AP
1) Client sends probe
2) AP sends probe response
3) Client sends auth request
4) AP sends auth response
5) Success message sent
6) Association request sent by client
7) Association response sent by AP
8) Client uses RSSI and SNR to determine what speed to send at

Management frames are sent at the …
Lowest possible rate

Data headers are sent at the…
Lowest possible rate

Actual data is sent at the…
Highest possible rate

If a wireless client is sending to a host on a different subnet and has never done so before, it will need to perform the ___ operation to find the ____ address of the __________ gateway
ARP, MAC, default

In an ARP frame sent from a client, the source address is the…the destination address is the…and the receiving address is the…
Host sending ARP
Broadcast because its an ARP broadcast
AP

What interframe space do ACK frames use?
SIFS – short interframe space

The LWAPP adds a ____________ _____________ frames travelling from the AP to the WLC
6 byte header

Who translates 802.11 frames into 802.3 frames in a centralized wireless setup?
The wireless LAN controller

The two main types of WLAN implementation methods are:
1) Distributed (autonomous AP’s)
2) Centralized (LAP + WLC)

WLC’s are responsible for… (5 things)
1) Security policies
2) Intrusion prevention
3) RF management
4) QoS
5) Mobility

LAP’s handle real-time MAC layer services while WLC’s handle non-real-time MAC layer services

Non real time MAC layer services handled by the WLC include:
1) Authentication
2) Association and reassociation (aka mobility)
3) Frame translation and bridging

Public networks broadcast their SSID in a beacon
But private networks wait for probe-requests

In a distributed setup, the address fields are setup as follows in the 802.11 frame:
Field 1: AP = receiving address
Field 2: Source address
Field 3: Destination address
Field 4: Unused

The Ethertype of LWAPP is…
0xBBBB

LWAPP can operate at ______ or ______
Layer 2 or layer 3

If LWAPP is operating at L2, do AP’s need IP’s?
No.

If LWAPP is operating at L3, do AP’s need IP’s?
Yes.

The trunking protocol is called…
802.1q

The trunking protocol adds a ____________ to 802.3 frames
4 byte header

The header added by 802.1q contains what 2 things
1) TPID
2) TCI

The TCI contains…
User priority, 1 bit canonical format, 12 bit VLAN ID

What are the reserved VLAN ID’s?
1 = default
1002 = FDDI
1003 = TR
1004 = FDDINET
1005 = TRNET

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