Wireless Security II – Flashcards
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Which OSI model layer picks the route packets take?
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Network
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Which layer of the OSI reference model permits the devices on the network to hold ongoing communications across the network?
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Session
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Which type of RF signal uses only a single frequency for transmission?
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Narrowband
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What is a disadvantage of narrowband transmissions?
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Interference from another radio signal and Require more power for the signal to be transmitted
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In FHSS, the amount of time needed to move from one frequency to another is the ________ time
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Hop
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DSSS uses a bit pattern called a _____code to transmit bits.
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Chipping
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DSSS makes it possible to share the frequency with similar devices by assigning each device a unique chipping code, a function known as what?
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Colocation
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How does OFDM work?
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Signals are broken up and the parts are sent in parallel
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Which system is preferred for 802.11 WLANs that operate at speeds in excess of 11 Mbps?
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OFDM
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IEEE has divided the ___ layer into two sublayers: Logical Link control (LLC) and Media Access Control (MAC)
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Data Link
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Which sublayer of the Physical Layer reformats data received from the MAC layer when transmitting?
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PLCP
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Which of the following is true about the frequencies 802.11b uses?
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14 total, only 11 used in the U.S.
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The Physical Layer Convergence Procedure (PLCP) standards for 802.11b are based on ______.
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DSSS
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The 802.11a standard enables faster data rates than 302.11b due to which of the following?
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Higher frequencies Increased Power
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Which is true about the 802.11a, 802.11b, 802.11g and 802.11n standards?
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802.11b and 802.11g use the 2.4 GHz band
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What techniques are used by vendors to achieve 2x mode for transmissions?
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Combining frequency channels, using different coding rate schemes, and increasing and reallocating the individual carriers
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Which of the following are enhancements of the 802.11n standard?
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40 MHz channels and variable guard interval
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What describes a BSS?
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A group of wireless devices that is served by a single access point
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What describes the process of a wireless device switching from one AP to another?
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Handoff
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A method of roaming between APs that are separated by a router is referred to as ______ .
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Mobile IP
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What is true about wireless network operation modes?
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A WLAN operating in ad hoc mode does not use an AP
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When a AP accepts or rejects a wireless device it sends a(n) ____ frame.
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Association Response
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At regular intervals the AP sends a ____ frame to both announce its presence and to provide the necessary information for other devices to join the network.
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Beacon
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What is true of passive scanning?
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A station listens for a beacon frame with an SSID for a set period of time
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On ESS networks that have multiple access points, the wireless device might actually receive beacon frames from several APs. Which AP would a wireless device generally choose in this case?
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The one with the strongest signal strength
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What is true about wireless authentication methods?
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Shared key authentication requires manual key installation
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What is the default authentication method according to the 802.11 standard?
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Open System
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What is the first step in shared key authentication?
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AP sends wireless device an authentication frame that contains a block of text known as the challenge text
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Following authentication, if the access point accepts the wireless device, it reserves memory space in the AP and establishes a(n) ____ ID for it.
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Association
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What is true about the CSMA/CD media access method?
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The hidden node problem makes it unsuitable for wireless networks
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The 802.11n standard adds a feature to CSMA/CA which is necessary for A-MPDU aggregation called _______.
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Virtual carrier sensing
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What is true about RTS/CTS?
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The RTS indicates the length of time needed for the transmission and ACK
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_____ effectively prevents collisions because every device must wait until it receives permission before it can transmit.
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Polling
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In which access method does the access point serve as the polling device?
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PCF
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A distributed WLAN architecture can be described as ______.
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An ESS that uses multiple autonomous access points
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The capability to prioritize different types of frames is known as ________.
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Quality of Service
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What technology works by inserting a tag header within the existing Ethernet packet?
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802.1Q trunking
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What is true of wireless VLANs in which the AP is responsible for separating packets for the correct VLAN?
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different VLANs are transmitted by the AP on different SSIDs
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What is a disadvantage of using autonomous APs?
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Adding a new AP to an existing WLAN may require multiple AP configurations
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What is true of a wireless mesh network?
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Only one AP must be connected to the wired network
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What should you deploy if you manage a public hotspot and want users to agree to a policy or present credentials before using the WLAN?
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Captive Portal AP
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What wired device is a WLC most similar to?
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Managed Switch
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Which network area are you likely to find LAN routers and Layer 3 switches?
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Workgroup Layer = Distribution Layer
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What system allows APs and other network equipment to be connected through the Internet and managed from one central location?
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Cloud management
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In an 802.11b network, which channels are non-overlapping?
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1, 6, 11
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What is NOT an advantage of single channel architecture?
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AP coverage does not overlap
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What happens when an AP sends a DTIM?
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All stations change to active mode
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What type of wireless network uses the ATIM window?
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IBSS
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What is NOT an enhanced power management technology?
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Continuous aware mode
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Which power management technology is designed to be used with MIMO devices?
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SMPS
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Narrowband transmissions require significant power for the signal to be transmitted because the signal must exceed the _________, or the total amount of outside interference, by a substantial margin.
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noise level
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the amount of time that a transmission occurs on a specific frequency is called the ___________.
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dwell time
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With FHSS, the sequence of changing frequencies is called the _______ code
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hopping
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A numeric value called a ____________ is assigned to a frequency range since using frequency range values can become tedious.
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channel
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The 40 MHz channels in an 802.11n WLAN are actually two 20 MHz channels that are _____ together
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bonded
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A(n) ____________ Service Set is a wireless network that does not use an access point.
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Independent Basic
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In shared key authentication, a wireless device sends an authentication frame to the AP. The AP sends back an authentication frame that contains a block of text known as the ____________.
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challenge text
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____________ is a means of reducing collisions and involves dividing the data to be transmitted from one large frame into several smaller ones.
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Fragmentation
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______________ are standard intervals between the transmissions of data frames and are used for special types of transmissions.
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Interframe Spaces
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An access method in which each device is asked, in sequence, if it wants to transmit, is called ________.
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polling
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A(n) ______________ access point has built-in intelligence fore wireless management, authentication, and encryption.
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autonomous
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In a(n) _________ WLAN architecture, multiple APs form a non-centralized network.
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distributed
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The capability to prioritize different types of frames is known as ____________
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Quality of Service
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Access points that support wireless __________ may support 160 or more multiple SSIDs
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VLANS
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The _____ layer is considered the backbone of the network and includes high-end switches and high-speed fiber cables.
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Core
