Wednesday, 20 June 2012

CCNA 1st Module Q & Ans


1 What are three measures of data transfer? (Choose three.)
goodput
frequency
amplitude
throughput
crosstalk
bandwidth.

2 In LAN installations where potential electrical hazards or electromagnetic interference may be present, what type of media is recommended for backbone cabling?
coax
fiber
Cat5e UTP
Cat6 UTP

3 STPWhich characteristics describe fiber optic cable? (Choose two.)
It is not affected by EMI or RFI.
Each pair of cables is wrapped in metallic foil.
It combines the technique of cancellation, shielding and twisting to protect data.
It has a maximum speed of 100 Mbps.
It is the most expensive type of LAN cabling.

4 Which of the following is a characteristic of single-mode fiber-optic cable?
generally uses LEDs as the light source
relatively larger core with multiple light paths
less expensive than multimode
generally uses lasers as the light source.

5 What is considered a benefit of wireless as a media choice?
more host mobility
lower security risks
reduced susceptibility to interference
less impact of the surroundings on the effective coverage area

6  What characteristic of UTP cable helps reduce the effects of interference?
the metal braiding in the shielding
the reflective cladding around core
the twisting of the wires in the cable
the insulating material in the outer jacket

7 What is a primary role of the Physical layer in transmitting data on the network?
create the signals that represent the bits in each frame on to the media
provide physical addressing to the devices
determine the path packets take through the network
control data access to the media.

8 Ethernet operates at which layers of the OSI model? (Choose two.)
Network layer
Transport layer
Physical layer
Application layer
Session layer
Data-link layer.

9 Which of the following describe interframe spacing? (Choose two.)
the minimum interval, measured in bit-times, that any station must wait before sending another frame
the maximum interval, measured in bit-times, that any station must wait before sending another frame
the 96-bit payload padding inserted into a frame to achieve a legal frame size
the 96-bit frame padding transmitted between frames to achieve proper synchronization
the time allowed for slow stations to process a frame and prepare for the next frame
the maximum interval within which a station must send another frame to avoid being considered unreachable
 

10 What three primary functions does data link layer encapsulation provide? (Choose three.)
addressing
error detection
frame delimiting
port identification
path determination
IP address resolution

11 When a collision occurs in a network using CSMA/CD, how do hosts with data to transmit respond after the backoff period has expired?
The hosts return to a listen-before-transmit mode.
The hosts creating the collision have priority to send data.
The hosts creating the collision retransmit the last 16 frames.
The hosts extend their delay period to allow for rapid transmission.

12 What are three functions of the upper data link sublayer in the OSI model? (Choose three.)
recognizes streams of bits
identifies the network layer protocol
makes the connection with the upper layers
identifies the source and destination applications
insulates network layer protocols from changes in physical equipment
determines the source of a transmission when multiple devices are transmitting

13 What does the IEEE 802.2 standard represent in Ethernet technologies?
MAC sublayer
Physical layer
Logical Link
Control sublayer
Network layer

14 Why do hosts on an Ethernet segment that experience a collision use a random delay before attempting to transmit a frame?
A random delay is used to ensure a collision-free link.
A random delay value for each device is assigned by the manufacturer.
A standard delay value could not be agreed upon among networking device vendors.
A random delay helps prevent the stations from experiencing another collision during the transmission.

15 Host A has an IP address of 172.16.225.93 and a mask of 255.255.248.0. Host A needs to communicate with a new host whose IP is 172.16.231.78. Host A performs the ANDing operation on the destination address. What two things will occur? (Choose two.)
Host A will change the destination IP to the IP of the nearest router and forward the packet.
Host A will broadcast an ARP request for the MAC of its default gateway.
A result of 172.16.225.0 will be obtained.
Host A will broadcast an ARP request for the MAC of the destination host.
A result of 172.16.224.0 will be obtained.
A result of 172.16.225.255 will be obtained.

16  Which of the following is a drawback of the CSMA/CD access method?
Collisions can decrease network performance.
It is more complex than non-deterministic protocols.
Deterministic media access protocols slow network performance.
CSMA/CD LAN technologies are only available at slower speeds than other LAN technologies

17 Ethernet operates at which layer of the TCP/IP network model?
application
physical
transport
internet
data link
network access

18  What is the primary purpose of ARP?
translate URLs to IP addresses
resolve IPv4 addresses to MAC addresses
provide dynamic IP configuration to network devices
convert internal private addresses to external public addresses.

19 Which statements correctly describe MAC addresses? (Choose three.)
dynamically assigned
copied into RAM during system startup
layer 3 address
contains a 3 byte OUI
6 bytes long
32 bits long

20  Which two features make switches preferable to hubs in Ethernet-based networks? (Choose two.)
reduction in cross-talk
minimizing of collisions
support for UTP cabling
division into broadcast domains
increase in the throughput of communications.

21 What are the two most commonly used media types in Ethernet networks today? (Choose two.)
coaxial thicknet
copper UTP
coaxial thinnet
optical fiber

22 Convert the binary number 10111010 into its hexadecimal equivalent. Select the correct answer from the list below.
85
90
BA
A1
B3
1C

23 After an Ethernet collision, when the backoff algorithm is invoked, which device has priority to transmit data?
the device involved in the collision with the lowest MAC address
the device involved in the collision with the lowest IP address
any device in the collision domain whose backoff timer expires first
those that began transmitting at the same time

24 Which three statements are true about the role of routers in the network? (Choose three.)They propagate broadcasts.
They enlarge collision domains.
They segment broadcast domains.
They interconnect different network technologies.
Each router interface requires a separate network or subnet.

They maintain a common frame format between LAN and WAN interfaces


25 A network administrator is required to use media in the network that can run up to 100 meters in cable length without using repeaters. The chosen media must be inexpensive and easily installed. The installation will be in a pre-existing building with limited cabling space. Which type of media would best meet these requirements?STP
UTP
coaxial
single-mode fiber
multimode fiber.

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