Tag Archives: CCNA Wireless answers

CCNA Wireless Chapter 18 and 19 Exam Answers

What is a WCS
Wireless control system

What is a WCS used for
To configure and monitor one or more controllers and their associated access points

The WCS has the same (5 things) as a WLC
1) Config
2) Perf. monitoring
3) Security
4) Fault management
5) Acc. options

WCS can provide a __________ view of multiple controllers and managed access points

What protocol does WCS manage devices with?

What operating systems can WCS run on?
Windows and Linux

What are the 3 versions of WCS?
1) Cisco WCS base
2) Cisco WCS location
3) Cisco WCS plus

What are some functions the Cisco WCS base fulfills?
Rogue AP detection
Ad-hoc detection
Containment functions for rogue devices
Map-based organization of AP RF coverage areas

The Cisco WCS location appliance performs computation based on _______ information from _______ WLC’s
RSSI info, from WLC’s

The WCS location compares what two things to map out a topology?
1) Real-time client RSSI
2) RF building characteristics

WCS + location appliance can display historical location data for up to ____________ clients

The only actual difference between the WCS location and the WCS plus is…
High availability

What Windows OS is compatible with WCS?
Server 2003 SP2 32bit

What Linux server OS is compatible with WCS?
RHEL server 5.x 32bit

Are any 64 bit Linux or Windows OS’s compatible with WCS?

The network summary page:
Shows the number of controllers, number of AP’s which controllers handle, total clients on those AP’s, out of service radios etc.

The controller summary page:
Shows specific information on a certain controller

The client page:
Shows information on clients connected to AP’s

The maps page:
Displays a topology of the network with colour codes for RSSI

RF fingerprinting is…
The calculation of the location of tracked devices

How does RF fingerprinting work?
Resolves location coordinates by determining how RF signals are received at every grid point within a building

What predicts the RF signals?

The location appliance is Linux and Java based/

The interface for the location appliance is defined in SOAP/XML

What is SOAP?
Simple object access protocol

SNMP operates between location appliances and the network

The 4 main applications for the location appliance are:
1) The location appliance can track 1500 mobile devices for 30 days
2) Work-flow automation and people tracking
3) WLAN security and NW control
4) RF capacity management/visibility

What two things are important to know when upgrading a WLC?
1) Software version
2) Hardware platform

Where would you find the software version in the GUI?

Where would you find the software version in the CLI?
show sysinfo

To find hardware platform on the GUI:

To find hardware platform on CLI:
show inventory

What are 3 ways to upgrade a WLC?
1) web interface
2) CLI
3) WCS

What protocols are required when accessing the web interface?
https, http, IP

What two files do all upgrade methods require?
1) Image archive
2) Boot loader

What series of WLC does not need both file types?
The 2100 series WLC

What does the image archive contain?
1) RTO – real time OS
2) Shell scripts/java apps to run GUI/CLI
3) AP firmware code

What is the naming format for the image archive?

What does the boot loader contain?
boot strap coding

What is the naming format for the boot loader?

On versions 4.1 or earlier, what was not required because it was included in the image archive?
The boot loader

Can the 2100 series WLC have its bootloader updated?

Both the 2 files for upgrading are encrypted and compressed with

A ________ server is used to put the software onto the controller

The TFTP server must be able to handle files larger than _____

To upgrade with the web interface what is the chain of clicks
commands > download file to controller window

The 5 parameters to enter when upgrading the software are:
1) TFTP server IP
2) File path
3) Maximum retries
4) Timeout
5) File name

What chain of commands is required to upgrade via the controller?
1) transfer download datatype code
2) transfer download mode tftp
3) transfer download serverip
4) transfer download path
5) transfer download filename
6) transfer download start
7) reset system

When the WLC is upgraded, the software on _____________ ______ is also upgraded
associated AP’s

How many AP’s can be upgraded at a time from the controller?

Configuration files from upgrade are stored in _________ and are executed when the controller ________
NVRAM, reboots

Configuration files on a WLC are in ____ format

XML files have a ______________________ attached to them
file integrity check

What happens if the integrity of the XML config file has been compromised?
it is not loaded

What performs this integrity or CRC check?
The controller

What happens to config files being uploaded to TFTP servers on software versions 5.2 and higher?
They are converted from XML files to plaintext

The two steps to uploading config files are:
1) Set upload parameters
2) Initiate the upload

What is the CLI process for this
1) Transfer upload mode tftp
2) Transfer upload datatype config
3) Transfer upload serverip
4) Transfer upload filename

Encrypting config files prior to transmission:
1) Transfer encrypt enable
2) Transfer encrypt set-key
3) Transfer upload

Are incremental config downloads supported?

To download config files what chain of commands is used?
1) Transfer download mode {tftp | ftp}
2) Transfer download datatype config
3) Transfer download serverip
4) Transfer download path
5) Transfer download filename

If encryption was enabled during upload what chain of commands is necessary?
1) Transfer encrypt enable
2) Transfer encrypt secret key
3) Transfer download start
4) Reset system

CCNA Wireless Chapter 17 Exam Answers

The 4 main threats to wireless NW’s are:
1) Ad-hoc NW formation
2) Rogue AP’s
3) Client missassociations
4) Directed wireless network attacks

What exactly is client missassociation?
An SSID profile is saved and active scanning is in operation, resulting in a client connecting to a network without knowing

What are 4 examples of directed wireless network attacks?
1) DoS
2) Recon probes
3) Authent. penetration
4) MITM attacks

How are directed wireless network attacks most often mitigated?
By authenticating and encrypting management frames.

What is this process of mitigation called exactly?
MFP: management frame protection

Management frames are usually sent unauthenticated and unencrypted

What does MFP do to management frames?
It digitally signs them

The two MFP modes are:
1) Infrastructure
2) Client

In infrastructure MFP,
A hash is generated for every management frame and placed before the FCS

Client MFP is only available with…
CCX 5+ “Cisco compatible extensions”

What does Client MFP/CCX do to management frames
It uses 802.11i to encrypt mgmt frames between the client and the AP

What does Client MFP/CCX defend most effectively against?
MITM and DoS attacks

In Client MFP/CCX, a key is generated for each AP

Why can’t mobile devices associate with MFP LAN’s?
They don’t have the processing power required for the extra encryption/authentication techniques

2 older security methods are:
1) SSID —> wrong SSID? no association
2) MAC authentication

What is open authentication?
It means no authentication key is required

What is the 4 step process to open authentication?
1) Probe
2) Probe response
3) Auth
4) Auth response

In WEP authentication, a ____ key is used to encrypt traffic
WEP key

In WEP, the header is not encrypted is not encrypted, but the the data is is

What encryption type does WEP use?

What are the 3 different sizes for WEP keys?
40 bits
104 bits
128 bits

In WEP, every key is combined with an….
Initialization vector

What is the basic process of WEP association?
1) Auth request
2) Challenge text packet
3) Challenge text encrypted by supplicant
4) If AP able to decrypt properly supplicant has the right key

EAP is defined under which two RFC’s?
2284, and 3748

EAP usually works alongside..
802.1x or RADIUS

The 4 EAP message types are
1) Request — to supplicant
2) Response — from supplicant
3) Success
4) Failure

What is Cisco LEAP?
A proprietary username/PW based auth. system between a client and a RADIUS server

What is Cisco LEAP’s weakness?
Susceptible to eavesdropping

EAP-TLS is defined under…
RFC 2716

EAP-TLS uses… _________ for authentication
Digital certificates

EAP-TLS uses…__________ to secure communications between client and RADIUS server

In EAP-TLS, the ________ and __________ authenticate to eachother
client and server

What is TLS based on?
SSL 3.0

What did EAP-TTLS add to EAP-TLS?

PEAP is very similar to..

What are the 3 authentication options for PEAP?

What is fast-reconnect?
Roaming b/t AP’s made seamless b/c TLS session ID’s are cached by WLC

The 3 roles of the 802.1x framework are…
1) Supplicant
2) Authenticator
3) Authentication server

It can be said that the authenticator controls __________ access to the network

If a Cisco ACS is being used as the Authentication server, more _____________ methods of authentication are available

802.1x: After the client sends a probe request to the AP, the AP will respond with a…
AP probe response which contains sec params.

What happens after the AP sends its probe response?
The client is associated but traffic is blocked until 802.1x auth is complete

The 802.1x authentication challenge is encrypted by

How does the client response to this challenge?
With a credential response

What does authenticator do with the credential response?
Converts it to a RADIUS access request and sends it to the AS

What does the AS do upon receiving the RADIUS access request?
It responds with a challenge that specifies what credentials are required of the supplicant

What happens if the client responds with the correct credentials?
The AS transmits a success message and encryption key

WPA2 is aka

What is a PMK?
Pairwise master key,
It is created on a RADIUS server when a client authenticates

Where is the PMK sent?
From the AS to the authenticator

What is PMK used for?
To encrypt the exchange of the temporal session key

What is the PMK derived from that results in the authenticator and supplicant having the same one?
It is derived from client information

PMK’s are used to make PTK’s and GTK’s.

PTK’s and GTK’s are made in a
4 way handshake process

WPA2-PSK is aka
personal mode

WPA2-PSK is encrypted with…
A 256 bit PMK

CCNA Wireless Chapter 15 and 16 Exam Answers

The Cisco mobility express solution can be… (2 things)
1) Standalone
2) Controller based

The Cisco mobility express solution is part of the…
SBCS: Cisco smart business communication system

The SBCS contains what 4 things
1) Cisco UC (unified communications) 500 series
2) Cisco unified IP phones
3) Cisco monitor director
4) Cisco mobility solution

How many clients can the Cisco UC 500 support?

The Cisco mobility solution consists of what 2 things
1) 526 Wi. Express controller
2) 521 Wi. Express AP

What are the 526 and 521 managed by
The Cisco config assistant

How many controllers and how many AP’s can be used in the cisco mobility solution?
2 controllers, 6 AP’s each = 12

The 521 AP has ________ antennas

Can the 521 AP associate with any other controllers?

Does the cisco mobility express solution support enterprise level LWAPP?
No, it is a reduced feature version

When doing the CLI setup, the normal selection for the 526 is…
Run primary image

Connection to the controller GUI is made via what protocol

When using the CCA, you must create a…
Community (group name for network)

What version of CCA is required to migrate standalone 521 AP’s to LW AP’s?
1.5 or later

The CCA discovers WLC’s via what two things
1) IP discovery
2) CDP

What is the Windows WiLAN config tool called?
WZC: Windows wireless zero configuration utility

What happens if profiles have already been configured on the WZC?
It tries to connect to those networks automatically

WZC clients use _________ scanning

Upon boot, WZC reports any networks being ________

What is active null scanning?
Probe requests that are sent with blank SSID fields

What happens if the WZC cannot establish any connections to infrastructure networks?
It tries ad-hoc networks

What happens if no ad-hoc networks are available for the WZC client to connect to?
It becomes an ad-hoc node and sends out beacons

WLAN profile on a MAC are handled by

What is the chain of clicks to configure a profile on AIRPORT
Open apple > System prefs > NW > Airport

In Linux that command line tool for joining WiLAN’s is called

The graphical version of Linux’s WiLAN config utility is called

What is CAM?
Constant awake mode, prevents NIC’s from going into any kind of power saving mode

What is the ADU?
The aironet desktop utility, used for configuration of WiLAN profiles

What is the ACAU?
Aironet client admin. utlity – for pushing out ADU to multiple clients

What is the SSU?
Cisco site survey tool, a minimal site survey program

What is the ASTU?
Aironet system tray utility

What 3 advantages does ADU have over WZC?
1) Channel determination
2) Auth. / sec. config determination
3) RSSI/SNR determination

3 main profiles in ADU are
1) Unsecure
2) 802.1x

How long are 802.1x WEP keys?
40-104 bits

Imported ADU profile have what extension?

The 4 connection quality colours in the SSU are..
Green, yellow, orange, red

What is connection quality quantified by by default?

What is the SSC?
Cisco secure services client, provides L2 802.1x user/device authentication

How are SSCAU profiles saved?
As XML files

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?

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. 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?

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?

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 /24 NW

CCNA Wireless Chapter 10 and 11 Exam Answers

The CUWN has 5 elements, which are…
1) Client devices
2) Mobility platform
3) Network unification
4) Network management
5) Unified advanced services

Cisco compatible extensions devices have:
1) Wireless mobility
2) QoS
3) NW management
4) Enhanced security

NW unification is…
A migration path into routing/switching platforms via WLC’s

The WLAN management interface for Cisco is called ..
WCS: Wireless control system

The control plane is…
AES-CCM encrypted

The data plane is..
Not encrypted

In a LWAPP header, a data message is C code _ and a control message is C code _
0, 1

Layer 3 LWAPP data traffic uses ports…
UDP src:1024 dst:12222

Layer 3 LWAPP control traffic uses ports…
UDP src:1024 dst:12223

4 stages of AP association to a WLC:
1) Discovery phase
2) Join phase
3) Authorization phase
4) Configuration phase

What LWAPP mode is attempted first?

Cisco prefers L3 discovery process over L2

The management IP of a WLC is handed out via…
Option 43 in a DHCP handout

For an AP to authenticate to a WLC, a _______________ is needed
x.509 certificate

What 2 types of x.509 certificates are there?
1) MIC: manufacturer installed cert
2) SSC: self-signed cert

If authentication is successsful, a _____________ is sent from the WLC to the LAP
Join response

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

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…

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

If LWAPP is operating at L2, do AP’s need IP’s?

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

The trunking protocol is called…

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

The header added by 802.1q contains what 2 things
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 7 Exam Answers

MAC layer provides 3 services, which are
1) Asynchronous data service
2) Security services
3) Media access control

With asynchronous data service…
Peer LLC’s exchange MSDU’s

With security services, there are 3 options:
Authentication, WEP or 802.11i

Every frame contains 3 things:
1) MAC header
2) Variable length frame body
3) FCS

The frame body is specific to…
1 of the 3 frame types in 802.11

How long are CRC’s?
4 bytes

The 3 802.11 frame types are:
1) Data
2) Control
3) Management

What do control frames do in 802.11?
Send CTS/RTS, ACK etc.

What do management frames do in 802.11?
Send associations and beacons

Management frames are ______________ to upper layer protocols
Not forwarded

802.11 is a CSMA/CA network, meaning it uses physical and virtual carrier sense mechanisms

Virtual carrier sense mechanisms….
Announce the use of media (NAV)

NAV stands for:
Network allocation vector

The distributed coordination function simply means the exchange of…
RTS’s and CTS’s

Both RTS’s and CTS’s contain a…
Duration field

The duration field is…
The time to tx data frame, ack frame, and inter fame spaces

Four diff. types of IFS’s:
1) SIFS: short inter frame space
2) PIFS: point coordination function inter frame space
3) DIFS: distributed coordination function inter frame space
4) EIFS: extended inter frame space

What does PCF do?
Creates contention free access to wireless network for tx devices, only available in infrastructure networks because AP is the polling master and central point of this optional method of access

The MAC layer can intentially _________ MSDU’s

When the MAC layer is reordering MSDU’s, what type of frames get priority?

The frame control field in the MAC header is how long
2 bytes

The protocol version field would be what for the current version?

The type bits would be set to what for each type of MAC frame
1) 00 – mgmt
2) 01- ctrl
3) 10 – data

The subtype field in the frame control field consists of…
Additional info about whatever frame type has been specified in the type section

The last half of the frame control field is…
1 byte of flags

If the destination is the distribution system, the To DS bit would be set to…

If the source is the distribution system, the From DS bit would be set to…

If a wireless distribution system is in play, the From and To DS bits are set to

If an ad-hoc network is in play, the From and To DS bits are set to

If the More flag is set to 1, what does this mean?
It means the MPDU is too large

What does 802.11 do with MPDU’s which are too large
It can fragment them like TCP does

If the retry flag is set to 1…
The frame has been transmitted before

If the power management flag is set to 1, the station is in
Power save mode

If the more data flag is set to 1….
The station is telling the receiver that the transmission is not complete and it should not enter power save mode

If the protected frame flag is set to 1…
The body is encrypted

If the order flag is set to 1…
An upper layer protocol requested strict order transmission, meaning the MAC layer will not reorder anything

The duration field has 2 functions:
1) Remaining duration
2) AID (association ID)

In the duration field, if bit 15 is 0 the field is…
The remaining duration

In the duration field, if bit 15 is 1 the field is…
The AID of the txing station

There are ___ address fields in an 802.11 frame

Data frames use how many address fields in an 802.11 frame?
3 or 4

Control and management frames can use as little as 1 address field in an 802.11 frame

The first 3 bytes of a MAC addr =
The OID of the vendor

The last 3 bytes of a MAC addr =
The unique ID of the MAC entity

5 types of addr’s in 802.11:
1) BSSID (ID’s boundaries)
2) Src
3) Dst (final dst)
4) Tx addr (last to tx)
5) Rx addr (next to rx)

The sequence control field has 2 subfields which are:
1) Fragment # (4 bits)
2) Frame seq # (12 bits)

The max frame body size for unencrypted frames is…
2304 bytes

The max frame body size for encrypted frames is…
2346 bytes

CCNA Wireless Chapter 6 Exam Answers

802.11e is…
QoS standard for WLANs

802.11h is…
Transmit power management
Changes transmit power to avoid creating interference for other devices

802.11i is…
Security standard

The original 802.11 standard used…
FHSS and DSSS to achieve 1 and 2 mbps

802.11 is a ___________ standard
layer 2 standard

802.11 is focussed on the delivery of…
MSDU’s between peer LLC devices

802.11 defines…
MAC and PHY sublayer characteristics

The 2 lesser used 802.11 standards are…
802.11ac – bonded channel 802.11n
802.11ad – WiGig 60ghz ISM band

LLC sublayer makes 802.11 look like…
every other L2 protocol to other high level protocols

The MAC layer ________, but the LLC layer __________
changes, stays the same

LLC is independent of…
1) topology
2) trans medium
3) MAC techniques used

LLC provides 3 basic services:
1) Unack’d connectionless
2) Ack’d conn-oriented
3) Ack’d connectionless

The 3 purposes of control frames are…
1) Information
2) Supervisory
3) Unnumbered

A 0 in the IG header bit means
individual address

A 1 in the IG header bit means
group address

A 0 in the CR header bit means

A 1 in the CR header bit means

In control frames, what does 00 signify?
Receive ready

In control frames, what does 01 signify?

In control frames, what does 10 signify?
Receiver not ready

In control frames, what does 11 signify?

STA’s are generally not a _______
Fixed location

STA’s can be ___________ in 802.11, but not 802.3
Hidden from eachother

802.11 can handle 2 types of stations…
Mobile and portable

In 802.11 context, mobile means… and portable means….
Mobile means device accesses LAN in motion
Portable means device can move but is stationary upon accessing LAN

The PLCP… (PHY layer definition)
Maps MAC sub layer data units to a framing format

The PMD…(PHY layer definition)
Defines characteristics of tx/rx through wireless medium

The PLME…(PHY layer definition)
Manages local PHY functions with MAC management entity

4 speeds of 802.11b
1,2,5.5 and 11mbps

802.11b uses DSSS and CCK

The chipping rate of 802.11b is…

802.11b uses the same PLCP as
The original 802.11

Total number of 802.11b channels…

Actual allowed number of channels for 802.11b for each country:
US: 11
ETSI: 13
JAPAN: All 14

Power levels for 802.11b…
US: 36dbm
ETSI: 20dbm

In 802.11b, channels 1.6 and 11 are referred to as..
Set 1

In 802.11b, channels 2,3,4,5,7,8,9,10 are referred to as…
Set 2

Channels 1, 6, and 11 exact frequencies are…
2412, 2439, and 2462 mhz

802.11a has how many channels

802.11a operates at what throughput potentially…

Does 802.11a have any backwards compatibility?

OFDM divides…
Communication channel into equally spaced frequency bands

OFDM creates ____ subcarriers each at _____ distance from eachother
52, 312.5khz

How many OFDM subcarriers are for data? and for syncing?
48, 4

OFDM is less sensitive to ________ than DSSS
Multipath interference

Four 802.11a modulation techniques…

802.11g throughput…
54mbps @ 2.4ghz

What is used for 20mbps+ connections in 802.11g?

What is used for speeds under 20mbps in 802.11g?

What is protection mode?
B clients on a G network are protected from OFDM which causes a significant decrease in throughput of 802.11g

Max possible throughput of 802.11n?

802.11n operates at…
2.4 and 5ghz

2 techniques for 802.11n
1) MIMO – uses maximum ratio combining
2) Channel bonding
3) Frame aggregation – multiple LLC’s put into one MAC frame

3 legacy modes of 802.11n…
1) greenfield (HT) – assumes no legacy devices
2) Legacy mode (non-HT) – 20mhz channels only, no channel bonding
3) HT mixed mode – RTS/CTS must be a/g format

802.11h is required by…
ETSI for 5ghz range

2 main features of 802.11h…
1) Dynamic frequency selection to avoid interference
2) Transmit control power – minimizes interference on other systems

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?

3.What is the wavelength of satellite waves?

4.As frequency increases, distance travelled

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

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…
2) N-connector
3) SMA (2 types)

36.2 subtypes of SMA connectors are

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?

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

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

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

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?

51.Do WWAN’s have high data rates?

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

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

55.The wired network is aka the…
Distribution system

56.2 or more BSA’s make an…

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

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

59.AP’s can have up to __ SSID’s

60.An AP offering more than one NW called a

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…

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

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…

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

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

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

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

32.The 5ghz band has _______ channels

33.The 5ghz band uses _________ modulation

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?

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?

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

51.MIMO is used by

52.As distance from AP increases, data rates

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