Homework 4 IT 300

To achieve a LAN capacity of 10 Gbps over UTP, Cat 5e is used, combined with M-ary modulation techniques and the use of hybrid canceller transceivers.

False

Both the 802.11 PCF and DCF periods require the use of either the frame exchange protocol or the four frame exchange protocol.

False

Both Bluetooth and ZigBee are configured as piconets using FHSS and TDD concepts

False

Select the correct statement(s) regarding 4B5B encoding.

it suffers from 20% overhead (information is only 80% of the data transmitted)

is used to map four information bits into a five-bit codeword

enables the use of simpler line coding techniques such as NRZ-Inverted

What are ways to increase data capacity on an 802.11 WLAN?

increase frequency bandwidth and/or operating frequency

implement M’ary modulation techniques

adopt MIMO to increase bit rate and help avoid multipath fading

What is true regarding the IEEE 802.11 WLAN standard?

both centralized and decentralized access methods are available in the 802.11 standard

In order to establish a centralized deterministic LAN, the physical and logical topologies must match

false

Which IEE 802.11 sub-layer must deal with the near-far problem

MAC

Increasing data capacity (i.e., throughput) on an 802.3 LAN using UTP can be done by:

increasing wire bandwidth (go from Cat5e to Cat6 or 7)

enabling both transmit and receive on a single wire pair using hybrid canceller transceiver

adopting a line coding technique with a higher M

A host controller interface acts as the direct radio layer interface between communications devices and the centralized controller

false

to increase bandwidth in later Wi-Fi specifications, channel bonding was adopted

true

Select the correct statement(s) regarding IEEE 802.15 core and adopted protocols.

parts of the core specifications are optional to better enable device customization

What is true about the Ethernet protocol?

the ethernet data link MAC sublayer is associated with the 48-bit ethernet address

What is true about the IEEE 802.3 Ethernet standard?

802.3 is a family of specifications, therefore each specification will identify different combinations of layer and 2 protocols/mediums/interfaces

What are some of the technologies used in Ethernet 100Base-T to achieve 100 Mbps?

4B5B combined with NRZI M=2 line coding

Select the correct statement(s) regarding the use of decentralized control over a LAN, WLAN, or WPAN.

decentralized control represents a medium access mode in which each network node determines when it can place data onto a shared medium

What is the principal reason why Wi-Fi standards eventually adopt OFDM over CCK?

to improve spectral efficiency

Select the correct statement(s) regarding shared Ethernet LANs.

all nodes on a shared ethernet LAN must have the ability to read the address of all incoming packets

only guided medium is used in a shared ethernet LAN

CSMA/CD is always required on a shared ethernet LAN

ZigBee is an IEEE 802.15 standard that operates on the ISM frequencies, and is a centrally controlled WPAN using FHSS and TDD similar to BT.  The only difference between ZigBee and BT is the bit rates and wake-up times.

false

Which method is used over IEEE 802.11 WLANs to limit data collisions caused by a hidden node?

four frame exchange protocol

IEEE 802.3 Media Access Control Layer (MAC) is responsible for what?

placement of frames onto the physical medium

responsible for CSMA/CD process

data encapsulation (framing, addressing, error detection)

What does 100BaseT mean?

100 Mbps, baseband, twisted pair

CSMA/CD is used as a collision control method for decentralized Ethernet LANs.

true

For IEEE 802.11 WLANs, what is a reason why DSSS (direct sequence spread spectrum) and OFDM (orthogonal frequency division multiplexing) are used?

both DSSS and OFDM are resilient in RFI environments and are spectrally efficient

Select the correct statement(s) regarding client-server and peer-to-peer (P2P) networks.

with client-server networks, you can centralize data storage

IEEE 802.3 Logical Link Layer (LLC) is responsible for what?

providing communications between the data link layer and the network layer

Which 802.15 sublayer protocol establishes centralized control and time division duplexing?

baseband

When can data collisions on a LAN occur when using decentralized access mode

at any time unless full duplex connections are made to network switches

Select the correct statement(s) regarding LAN physical and logical topologies.

a LAN’s physical topology may differ from its logical topology

Which IEEE 802.11 sub-layer ensures proper mapping between the PMD and MAC sublayers?

PLCP