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22 Cards in this Set
- Front
- Back
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A wireless NIC performs the same functions as a wired NIC except that ___________.
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it uses antenna instead of a wired connection
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Wireless NICs are available in each of the following formats except _________.
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PC card Type 1
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Some vendors have already announced plans to integrate the components of a wireless NIC directly onto the notebook's ___________.
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motherboard
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Which of the following is not a function of an access point?
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serves as a router
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The range of an access point acting as the base station is approximately ________.
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375feet
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The highest data rate for an 802.11 diffused infrared WLAN is about ______ Mbps.
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2 Mbps
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The IEEE 802.11 standards that outline the specifications for infrared WLANs are based on __________ transmissions.
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Diffused
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Power over Ethernet delivers power to an access point through the unused wires in a standard unshielded twisted pair (UTP) Ethernet cable. True or False?
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True
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In ad hoc mode, the wireless clients communicate directly with the access point. True or false?
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False
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An Extended Service Set (ESS) is two or more BSS wireless networks. True or false?
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True
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On a regular basis, wireless clients will survey all the radio frequencies to determine if a different access point can provide better service. True or false?
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True
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Network managers like to subdivide networks into smaller units known as subnets because this makes it easier to manage the entire network. True or false?
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True
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The IEEE _____________ standard defines a local area network that provides cable-free data access for clients that are either mobile or in a fixed location at a rate up to 2 Mbps.
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802.11 or 802.11-1999
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Because all of the IEEE WLAN features are isolated in the PHY and __________ layers, any network operating system or LAN application will run on a WLAN without any modification necessary.
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MAC
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The Physical Layer Convergence Procedure Standards (PLCP) for 802.11b are based on _____________ spread spectrum (DSSS).
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direct sequence
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A PLCP frame is made up of three parts, which are the preamble, the header, and the __________.
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data
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The PLCP frame preamble and header are always transmitted at 1 Mbps. What are the advantages and disadvantages of this?
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Advantages: Backwards compatibility with 802.11; Better chance that a distant receiving station will be able to receive the frame and negotiate the speed for the data portion. Disadvantages: in a network where distances are short and all clients are 11 Mbps capable, this may slow down the transmissions.
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Explain how Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) is different from Carrier Sense Multiple Access with Collision Detection (CSMA/CD) works.
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in CSMA/CD on a wired network, collisions can be detected whereas in an RF environment, using the same frequency to transmit and receive, collisions cannot be detected.
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Explain how packet acknowledgment works.
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Students should mention, as a minimum, that at the end of the transmission of each frame, the receiver, upon establishing that the frame was received correctly, must acknowledge the frame during the SIFS
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What is RTS/CTS? What are its advantages and how does it work?
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Request-to-send/Clear-to-send. It is a system used to avoid contention on the network, when the medium is very busy. Each client must request permission to send by sending an RTS to the AP. If and when the client receives a Clear-to-send from the AP, it can then begin sending the frame.
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What is polling? How does it differ from contention?
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In PCF mode the AP will poll, or ask each client in turn if it has anything to transmit. Clients are not allowed to transmit unless they are asked, unlike contention, or DCF mode, in which clients will listen to the medium and begin transmitting after the end of the DIFS, provided that they do not detect any traffic.
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How can the 4-PPM transmit at twice the speed of 16-PPM?
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4-PPM takes only 16 pulses to send 8 bits, whereas 16-PPM would take 32 pulses to send the same 8 bits.
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