Free Download New CCNA 640-802 Question Answer 2 | Latest Cisco CCNA Certification Dumps

New CCNA 640-802 Question Answer 2

By PassGuide CCNA Training Materials and Practice Tests | September 1, 2008

When a cable modem is being provisioned to operate with a host system for Internet
services, which two options must occur before Layer 1 and 2 connectivity can
occur? (Choose two)

A. The cable modem must request an IP address and core configuration information from
a Dynamic Host Configuration Protocol (DHCP) server.
B. The cable modem powering up must scan and lock on the RF data channel in the
downstream path.
C. The modem must request a DOCSIS configuration file from a TFTP server.
D. The cable modem must register with the CMTS.
E. The modem must read specific maintenance messages in the downstream path.
Answer: B, E
Explanation:
According to the DOCSIS (Data-over-Cable Service Interface Specifications) when you
first power up a cable modem it starts scanning (starting at a low frequency) for a cable
signal. When it ‘hears’ a cable modem stream it listens for a broadcast (from the service
provider) which contains information (ie. frequency) needed to talk back with the head
end. It then ‘talks back’ and if it communicates the right authentication information, it is
allowed to proceed. Once these steps are completed, layers 1 and 2 will be operational.
QUESTION NO: 8
How is cable broadband technology able to transmit downstream and upstream
data while at the same time delivering television content?

A. The cable operator uses the VHF hyperband to transmit and receive data signals.
B. The cable operator assigns any available spectrum to data, depending on how its own
television spectrum is being used.
C. The cable operator uses specific bandwidths for data signals specified by DOCSIS.
D. The cable operator places its data signals into clean areas where there is no
interference from noise or other signals.
Answer: C
QUESTION NO: 9
certifyme.comoperates a DSL network. What does the “dsl operating-mode auto”
command configure on a Cisco router?

A. It configures a Cisco router to automatically detect the proper modulation method to
use when connecting an ATM interface.
B. It configures a Cisco router to automatically detect the proper DSL type (ADSL,
IDSL, HDSL, VDSL) to use when connecting an ATM interface.
C. It configures a Cisco router to automatically detect the proper encapsulation method to
use when connecting an ATM interface.
D. It configures a Cisco router to automatically detect the proper authentication method
to use when connecting an ATM interface.
E. None of the above
Answer: A
Explanation:
dsloperating-mode auto interface configuration command to specify that the router
automatically detect the DSL modulation that the service provider is using and set the
DSL modulation to match. An incompatible DSL modulation configuration can result in
failure to establish a DSL connection to the DSLAM of the service provider
Example:
QUESTION 18:

A host computer has been correctly configured with a static IP address, but the default gateway is incorrectly set. Which layer of the OSI model will be first affected by this configuration error?

A. Layer 1
B. Layer 2
C. Layer 3
D. Layer 4
E. Layer 5
F. Layer 6
E. Layer 7
Answer: C Explanation:
IP Addressing and IP routing resides on the OSI Network layer, which is layer 3.

QUESTION 19:

Which layer of the OSI reference model is responsible for ensuring reliable end-to-end delivery of data?

A. Application B. Presentation C. Session
D. Transport
E. Network
F. Data-Link
Answer: D Explanation:
A key function of the transport layer is to provide connection services for the protocols and applications that run at the levels above it. These can be categorized as either connection-oriented services or connectionless services. Some protocol suites, such as TCP/IP, provide both a connection-oriented and a connectionless transport layer
protocol, to suit the needs of different applications.
The transport layer is also the place in the layer stack where functions are normally included to add features to end-to-end data transport. Where network layer protocols are normally concerned with just “best effort” communications, where delivery is not
guaranteed. Transport layer protocols are given intelligence in the form of algorithms that
ensure that reliable and efficient communication between devices takes place. This encompasses several related jobs, including lost transmission detection and handling, and managing the rate at which data is sent to ensure that the receiving device is not

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overwhelmed.
Transmission quality, meaning ensuring that transmissions are received as sent, is so important that some networking references define the transport layer on the basis of reliability and flow-control functions. However, not all transport layer protocols provide these services. Just as a protocol suite may have a connection-oriented and a
connectionless transport layer protocol, it may also have one that provides reliability and
data management services, and one that does not. Again, this is the case with TCP/IP:
there is one main transport layer protocol; TCP, that includes reliability and flow control features, and a second, UDP, that doesn’t.

QUESTION 20:

At which OSI layer is a logical path created between two host systems named CK1
and CK2 on the Certifyme LAN?

A. Physical B. Session C. Data link D. Transport E. Network
F. Application
G. Presentation
Answer: E Explanation:
The Network layer (also called layer 3) manages device addressing, tracks the location of devices on the network, and determines the best way to move data, which means that the Network layer must transport traffic between devices that aren’t locally attached. Routers
(layer 3 devices) are specified at the Network layer and provide the routing services within an internetwork.

QUESTION 21:

Which OSI layer is associated with the following: The acknowledgement of transmissions, sequencing, and flow control across a network?

A. Layer 2
B. Layer 3
C. Layer 4
D. Layer 5
E. Layer 6
F. Layer 7

Answer: C

640-802

Explanation:
The Transport layer (Layer 4) defines several functions, including the choice of
protocols. The most important Layer 4 functions are error recovery and flow control. The transport layer may provide for retransmission, i.e., error recovery, and may use flow control to prevent unnecessary congestion by attempting to send data at a rate that the network can accommodate, or it might not, depending on the choice of protocols. Multiplexing of incoming data for different flows to applications on the same host is also performed. Reordering of the incoming data stream when packets arrive out of order is included. Examples include: TCP, UDP, and SPX.

QUESTION 22:

Which OSI layer header contains the address of a destination host that is on another network?

A. Application B. Presentation C. Session
D. Transport E. Network F. Data link G. Physical
Answer: E Explanation:
Only network address contains this information. To transmit the packets the sender uses
network address and datalink address. But the layer 2 address represents just the address
of the next hop device on the way to the sender. It is changed on each hop. Network address remains the same.

QUESTION 23:

Which of the following correctly describe steps in the OSI data encapsulation process? (Choose two)

A. The presentation layer translates bits into voltages for transmission across the physical link.
B. The transport layer divides a data stream into segments and adds reliability and flow control information.
C. Packets are created when the network layer adds Layer 3 addresses and control information to a segment.
D. The data link layer adds physical source and destination addresses and an FCS to the segment.
E. Packets are created when the network layer encapsulates a frame with source and destination host addresses and protocol-related control information.

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Answer: B, C

Explanation:
The Transport Layer:
You can think of the transport layer of the OSI model as a boundary between the upper
and lower protocols. The transport layer provides a data transport service that shields the upper layers from transport implementation issues such as the reliability of a connection. The transport layer provides mechanisms for:
Segmenting upper layer application
The establishment, maintenance, and orderly termination of virtual circuits information flow control and reliability via TCP
Transport fault detection and recovery
The Network Layer:
Layer three of the OSI model is the network layer.
The network layer creates and sends packets from source network to destination network.
it provides consistent end-to-end packet delivery service and control information
it creates and uses layer3 addresses for use in path determination and to forward packets.
Incorrect Answers:
A: This correctly describes the physical layer, not the presentation layer.
D: Although the data link layer adds physical (MAC) source and destination addresses, it adds it to a frame, not a segment.
E: Packets are encapsulated, not frames.

QUESTION 24:

When files are transferred between a host and an FTP server, the data is divided
into smaller pieces for transmission. As these pieces arrive at the destination host, they must be reassembled to reconstruct the original file. What provides for the reassembly of these pieces into the correct order?

A. The sequence number in the TCP header
B. The Start Frame Delimiter in the 802.3 Preamble
C. The TTL in the IP header
D. The acknowledgement number in the segment header
E. The frame check sequence in the Ethernet frame trailer
Answer: A Explanation:
The Transport layer can provide reliable networking via acknowledgments, sequencing, and flow control.
Acknowledgments Delivered segments are acknowledged to the sender. If they are not acknowledged, the sender will retransmit.