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Who developed the series of standards that defines WLANs?
- InternationalTelecommunication Union-Radio Communication Sector (ITU-R)
- Institute ofElectrical and Electronics Engineers (IEEE)
- Wi-Fi Alliance
- FederalCommunications Commission (FCC)
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What are the unlicensed radio bands?
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What is the name of the 900MHz unlicensed radio band?
ISM
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What is the name of the 2.4GHz unlicensed radio band?
ISM
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What is the name of the 95GHz unlicensed radio band?
U-NII
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Which unlicensed radio bands are named ISM?
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Which unlicensed radio band is named U-NII?
5GHZ
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What are some of the uses of the 900MHz unlicensed radio band?
- Older cordelss phones
- GSM cell phones
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What are some of the uses of the 2.4GHz unlicensed radio band?
- 802.11
- 802.11b
- 802.11g
- 802.11n
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What are some of the uses of the 5GHz unlicensed radio band?
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Which unlicensed radio band is used for Older cordelss phones and GSM cell phones?
900MHz
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Which unlicensed radio band is used for 802.11, 802.11b, 802.11g, 802.11n?
2.4GHz
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Which unlicensed radio band is used for 802.11a, 802.11n?
5GHz
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Which unlicensed radio bands is use 802.11n?
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What does ISM stand for?
Industrial,Scientific, Medical
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What does U-NII stand for?
Unlicensed National Information Infrastructure
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What year was 802.11 standardized?
1997
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What year was 802.11a standardized?
1999
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What year was 802.11b standardized?
1999
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What year was 802.11g standardized?
2003
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What year was 802.11n standardized?
2008
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Which 802.11 was standardized in 1997?
802.11
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Which 802.11 was standardized in 1999?
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Which 802.11 was standardized in 2003?
802.11g
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Which 802.11 was standardized in 2008?
802.11n
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What is the 802.11 standard also known as?
legacy
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What is the max speed for 802.11?
11Mbps
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How many channels does 802.11 use?
11
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Which radio frequency does 802.11 use?
2.4GHz
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What is FHSS?
arandom, rapid sequence to statistically avoid interference from other devicesusing the same frequencies
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What is the max speed for 802.11a for FHSS?
11Mbps
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What is the max speed for 802.11n for FHSS?
11 Mbps per stream
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What is the max speed for 802.11a for OFDM?
54Mbps
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What is the max speed for 802.11g for OFDM?
54Mbps
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What is the max speed for 802.11n for OFDM?
600Mbps
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What is the assigned frequency for 802.11?
2.4GHz
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What is the assigned frequency for 802.11a?
5GHz
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What is the assigned frequency for 802.11b?
2.4GHz
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What is the assigned frequency for 802.11g?
2.4GHz
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What is the assigned frequency for 802.11n?
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Which 802.11s use frequency 2.4GHz?
- 802.11
- 802.11b
- 802.11g
- 802.11n
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Which 802.11s use frequency 5GHz?
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How many channels are available for 802.11?
11
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How many channels are available for 802.11a?
23
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How many channels are available for 802.11b?
11
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How many channels are available for 802.11g?
11
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How many channels are available for 802.11n?
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Which 802.11s have 11 channels available?
- 802.11
- 802.11b
- 802.11g
- 802.11n
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Which 802.11s have 23 channels available?
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What is the range for 802.11?
75 feet
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What is the range for 802.11a?
75 feet
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What is the range for 802.11b?
150 feet
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What is the range for 802.11g?
150 feet
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What is the range for 802.11n?
500 feet
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Which 802.11s has a range of 75 feet?
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Which 802.11s has a range of 150 feet?
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Which 802.11s has a range of 500 feet?
802.11n
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What is a big advantage of using 5GHz frequency?
- it is immune to common 2.4GHz emissions, such as from cordless phones, babymonitors, microwave ovens, and many of the wireless conveniences we take for granted that can really interfere with WLAN transmissions in the 2.4GHz range.
- higherfrequencies mean smaller antennas, which means we can increase the antenna gain
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What is a big disadvantage of using 5GHz frequency?
the higher frequencies are more easily absorbed by structures and furniture,reducing the effective range
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Why is it that mostly enterprise customers who like 802.11a?
because it never caught on with the general public so the risk of interference and security breaches was reduced.
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What is the actual frequency range used in 2.4GHz WLANs?
2.402 - 2.4382
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Which WLAN technology hit the market first, 802.11a or 802.11b?
802.11b
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What are the typical channels used for 2.4GHZ WLANs and why?
- 1
- 6
- 11
- These channels do not cross each other like the other channels do.
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Which 802.11 is considered DSSS?
802.11b
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What does DSSS stand for?
Direct Sequence Spread Spectrum
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What does OFDM stand for?
OrthogonalFrequency Division Multiplexing
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What does FHSS stand for?
FrequencyHopping Spread Spectrum
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Which 802.11 standard is the most popular?
802.11g
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What are the different WLAN operational modes?
- Ad Hoc Mode
- Infrastructure Mode
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What is Ad Hoc mode?
A connection establed between only 2 devices directly without the use of an AP.
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What is Infrastucture mode?
an AP is required because the client devices cannot send directly to each other;they must send through the AP. The AP, in turn, handles all the wireless client data and provides the connection to the wired LAN by way of its connection tothe switch.
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What are the 2 distinctions that Cisco makes within infrastructure mode?
- Autonomous Mode
- Lightweight Mode
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What is Autonomous Mode?
each AP is managed separately and sends wireless client data into the networkitself.
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What is Lightweight Mode?
each AP associates with a WLAN controller, a special device that provides a singlepoint for management and security of multiple APs in the network.
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What is the protocol used that a WLAN controller uses to manage APs in Lightweight mode?
LightweightAccess Point Protocol (LWAPP)
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What does BSS stand for?
Basic Service Set
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What does ESS stand for?
Extended Service Set
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What is a BSS configuration?
a single AP that provides network connectivity for its associated clients.
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What is an ESS configuration?
eachAP still defines a BSS, but the group of APs and their BSSs form the ESS. Themain advantage is that clients can roam between the overlapping coverage areasof the individual APs' BSSs, without losing the functionality of theirconnection to the ESS and thus to the network.
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What does SSID stand for?
Service Set Identifier
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What is an SSID?
just a name for a WLAN
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What are the threats to WLANs?
- War Driving
- Hackers
- Internal
- Rogue APs
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What is War Driving?
refers to driving around with a laptop, looking for unsecured APs to connect to and get free Internet access.
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Why are hackers a threat?
they are looking for interesting or useful information such as credit card numbersor other protected data, or else they just want to mess up someone's networkout of malice or boredom.
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What is an internal threat?
malicious or ignorant actions by the company's own employees. The classic example is the employee who buys a little AP and plugs it into the network drop in their office. The defaults on consumer APs are typically no security at all; now a hacker can connect easily and steal access or information.
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What is a rogue AP?
APs put in place in a WLAN without authorization.
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What are the WLAN security Methods?
- Authentication
- Encryption
- Intrusion Detection/Intrusion Prevention
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How does Authentication provide security?
requires all clients connecting to an AP to provide some (hopefully secret) information called a key to prove that they are authorized to connect
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How does Encryption provide security?
encrypting it into a stream of gibberish that only another device with the correct key anddecryption formula can unscramble.
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How does Intrusion Detection and Intrusion Prevention provide security?
Cisco's Structured Wireless-Aware Network architecture (SWAN) includes several devices and tools that improve the manageability and security of WLANs. They detect Rogue APs and shuts them down.
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What are the WLAN Security Standards?
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What does WEP stand for?
Wired Equivalent Privacy
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What does WEP do?
WEP uses a static preshared key system, meaning that all the APs and all the clientsmust have the same key string configured in order to authenticate and transmitencrypted data.
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What is the problem with using WEP?
- itis an administrative headache to change the keys, which means they don't changeoften, which is not good.
- theencryption method used was pretty weak
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Should WEP be considered aviable security method in current WLAN deployments?
no
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What solution to WEPs problems did Cisco create?
ExtensibleAuthentication Protocol (EAP)
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What improvemnts did Cisco make with EAP over WEP?
- Dynamic Key Exchange
- User Authentication with 802.1x
- Unique Key per Packet
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How does Dynamic Key Exchange improve security?
it allows the key to be secretly agreed upon by the devices themselves
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How does Authentication with 802.1x improve security?
requiring the user to supply a username/ password package when attempting to connect
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What does WPA stand for?
Wi-Fi Protected Access
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How does WPA use Dynamic keying that cisco does not?
TemporalKey Integrity Protocol (TKIP)
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What security method did IEEE release in 2005 that uses dynamic keying,authentication, and very strong encryption using the Advanced EncryptionStandard (AES) algorithm?
802.11i
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What is 802.11i?
- A security feature that includes:
- Dynamic Keying
- Authentication
- Advanced Encryption Standard (AES) algorithm
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is 802.11i backward compatible?
no
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Whaqt dows the Wi-Fi Alliance call 802.11i?
WPA2
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