Questão 1
Questão
In version field of IPv4 header, when machine is using some other version of IPv4 then datagram is
Responda
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Rejected
-
Accepted
-
Interpreted
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Interpreted incorrectly
Questão 2
Questão
Network layer at source is responsible for creating a packet from data coming from another
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Station
-
Link
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Node
-
Protocol
Questão 3
Questão
Header of datagram in IPv4 has
Responda
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0 to 20 bytes
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20 to 40 bytes
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20 to 60 bytes
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20 to 80 bytes
Questão 4
Questão
An IPv4 datagram can encapsulate data from several higher-level protocols such as UDP, ICMP, IGMP and
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TCP protocols
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CDM protocols
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ATM protocols
-
IEEE protocols
Questão 5
Questão
To record Internet routers of IPv4, that handles datagram is responsibility of
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Record protocol
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Record Data
-
Record Route
-
Record Header
Questão 6
Questão
Internet has chosen datagram approach to switching in the
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Data Link Layer
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Network Layer
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Physical Layer
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Presentation Layer
Questão 7
Questão
In IPv4 protocol, each datagram is handled
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Independently
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Dependently
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Priority basis
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Systematically
Questão 8
Responda
-
Close Circuit Transmission
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Congestion Controlled Traffic
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Congestion Controlled Transmission
-
Close Circuit Traffic
Questão 9
Questão
Communication between a computer and a keyboard involves ______________ transmission
Responda
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Automatic
-
Half-duplex
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Full-duplex
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Single direction
Questão 10
Questão
Three or more devices share a link in ________ connection
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Unipoint
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Multipoint
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Point to point
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None
Questão 11
Questão
In asynchronous serial communication the physical layer provide
Questão 12
Questão
The physical layer is responsible for
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line coding
-
channel coding
-
modulation
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all of the mentioned
Questão 13
Questão
A single channel is shared by multiple signals by
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analog modulation
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digital modulation
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multiplexing
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none
Questão 14
Questão
Wireless transmission can be done via
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radio waves
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microwaves
-
infrared
-
all of the mentioned
Questão 15
Questão
Which is not a application layer protocol?
Questão 16
Questão
The packet of information at the application layer is called __________
Responda
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Packet
-
Message
-
Segment
-
Frame
Questão 17
Questão
Which one of the following is an architecture paradigms?
Questão 18
Questão
Application layer offers _______ service
Questão 19
Questão
E-mail is _________
Questão 20
Questão
To deliver a message to the correct application program running on a host, the _______ address must be consulted
Questão 21
Questão
Layers four and five of the Internet protocol stack are implemented in the end systems but not in the routers in the network core
Questão 22
Questão
With ADSL, each subscriber gets more downstream bandwidth than upstream bandwidth
Questão 23
Questão
Two packets A and B are sent in that order through a connection-oriented communication network. They could arrive at the destination:
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in any order, after having traversed the same route.
-
only in the order A-B, after possibly having traversed different routes.
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in any order, after possibly having traversed different routes
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only in the order A-B, after having traversed the same route.
Questão 24
Questão
Two packets A and B are sent in that order through a connectionless communication network. They will arrive at the destination:
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in any order, after possibly having traversed
-
in the order A-B, after having traversed the same route
-
in any order, after having traversed the same route.
-
in the order A-B, after possibly having traversed different routes
Questão 25
Questão
The Internet received its name in the 1980s because:
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it was an interim (temporary) design of what it later became, but the name stuck.
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it was meant to be a network internal to the United States Department of Defense.
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it consisted of many interconnected networks.
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it achieved international scope with the addition of the City University of London.
Questão 26
Questão
All store-and-forward networks are
Questão 27
Questão
When a student in Hong Kong uses her computer to have a voice conversation with a teacher in Pittsburgh, the application she uses requires that the network deliver bits at a modest but constant bit rate. This is because, even though voice can be faithfully encoded in less than 64 Kbps, the late arrival of a voice sample produces a noticeable and unpleasant sound effect. Which of the following switching options will give you better quality?
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Packet-switched
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Message-switched.
-
Space-switched.
-
Circuit-switched
Questão 28
Questão
The Date: header in the HTTP response message indicates when the object in the response was last modified.
Questão 29
Questão
The process that sends messages into, and receives messages from, the network through a software interface is called a socket.
Questão 30
Questão
The transfer of an html file from one host to another is:
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loss-tolerant and time sensitive
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loss-intolerant and time sensitive.
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loss-intolerant and time insensitive.
-
none of the above
Questão 31
Questão
A browser will generate header lines as a function of
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browser type and version.
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user configuration of browser.whether the browser has a cached version of the requested object.
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whether the browser has a cached version of the requested object.
-
all of the above
Questão 32
Responda
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to transfer messages from one mail server to another
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to transfer messages from mail server to a user agent.
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to define the format of message headers.
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all of the above.
Questão 33
Questão
DNS resource record has Type=MX. Then:
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Value is the hostname of the DNS server that is authoritative for Name.
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Value is the IP address of the mail server that has the alias hostname Name.
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Value is the hostname of the mail server that has the alias hostname Name.
-
none of the above.
Questão 34
Questão
Local DNS name servers:
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-
cache resource records, but discard them after a period of time that is on the order of a few days
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cache resource records and never discard them.
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obtain resource records from Web caches.
-
never cache resource records
Questão 35
Questão
Consider an HTTP Web server using persistent connections. Suppose the server spawns a separate process for each client that connects to the server. Then each of these spawned processes will have different server port numbers.
Questão 36
Questão
The size of the TCP RcvWindow never changes throughout the duration of the connection
Questão 37
Questão
The TCP segment has a field in its header for RcvWindow
Questão 38
Questão
Suppose host A sends host B one segment with sequence number 38 and 4 bytes of data. Then in this same segment the acknowledgement number is necessarily 42
Questão 39
Questão
The MSS is the maximum size of a TCP segment including headers
Questão 40
Questão
When a TCP segment arrives to a host, the socket to which the segment is directed depends on
Questão 41
Questão
UDP has which of the following characteristics
Questão 42
Questão
When a UDP segment arrives to a host, in order to direct the segment to the appropriate socket, the OS uses
Questão 43
Questão
The stop-and-wait protocol is highly inefficient when there is a
Responda
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large distance between source and destination and the transmission rate is low
-
short distance between source and destination and the transmission rate is high
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large distance between source and destination and the transmission rate is high
-
short distance between source and destination and the transmission rate is low
Questão 44
Questão
Pipelining requires which of the following
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transmitting many packets before receiving acknowledgements
-
unique sequence numbers for each in-transit packet
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sender-side buffering of unacknowledged packets
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all of the above
Questão 45
Questão
Suppose a client sends an HTTP request message with the If-modified-since: header. Suppose the object in a server has not changed since the last time a client retrieved the object. Then the server will send a response message with the status code
Responda
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404 Not Foun
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200 OK
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304 Not Modified
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none of the above
Questão 46
Questão
Streams are not needed in which of the following programs
Responda
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TCPserver
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UDPserver
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TCPclient
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UDPclient
Questão 47
Questão
For BitTorrent, which of the following is true
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Although a peer may have 50 concurrent TCP connections with other peers, at any given instant of time it sends data to less than 10 other peers.
-
At a given instant of time, a peer A may upload to a peer B, even if peer B is not sending anything to A.
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Among the chunks that a peer does not have, the peer will request chunks that appear to be relatively rare in the torrent.
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All of the above
Questão 48
Questão
Consider the latency model for dynamic congestion windows. Which of the following components contribute to latency?
Questão 49
Questão
TCP applies fast retransmit to a segment when
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it estimates unusually large RTTs
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it receives three ACKs for an earlier segment
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the segment's timer expires
-
none of the above
Questão 50
Questão
Nmap is often used to
Responda
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do port scans over a range of ports at a target host
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measure throughput between hosts
-
measure round-trip times between hosts
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decipher encrypted traffic
Questão 51
Questão
With SYN cookies, when a server receives a SYN segment, it returns a SYNACK with
Responda
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an initial sequence number that is a hash of the IP addresses and port numbers in the SYN segment (as well as of other things)
-
initial sequence number 1
-
a randomly chosen initial sequence number
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none of the above
Questão 52
Questão
Before sending a packet into a datagram network, the source must determine all of the links that packet will traverse between source and destination
Questão 53
Questão
The primary role of a router is to forward datagrams from input links to output links
Questão 54
Questão
A forwarding table is
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Used to find the proper interface to which the input interface should forward a packet
-
Configured using a centralized routing algorithm
-
Configured through routing protocol messages received by router
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A and C
-
B and C
Questão 55
Questão
How are routing paths calculated?
Responda
-
The full route is mapped out in the datagram’s header.
-
Paths are calculated by routing algorithms.
-
Datagrams always flow on the same path and don’t need to be calculated.
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The path is calculated based on available network bandwidth
Questão 56
Questão
A channel partitioning protocol has which of the following characteristics forwarding table is
Questão 57
Questão
Match the following network service to the correct definition
Responda
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Guaranteed Delivery - Guarantees a packet will arrive at its destination
-
Guaranteed Delivery with Bounded Delay- Guarantees delivery within a specified host-to-host delay bound
-
Guaranteed Maximum Jitter - Guarantees the amount of time between the transmission of two successive packets at the sender is
equal to the amount of time between their receipt at the destination.
-
Я НЕ ЗНАЮ КАК ДОБАВИТЬ DROP DOWN ВОПРОС ПОЭТОМУ ПРОСТО ЗАПОМНИ ORDER
Questão 58
Questão
An ARP query packet is encapsulated in an IP datagram.
Questão 59
Questão
Ethernet provides which of the following services to the network layer
error detection
Responda
-
error detection
-
flow control
-
reliable data transfer
-
all of the above
Questão 60
Questão
For Ethernet, if an adapter determines that a frame it has just received is addressed to a different adapter
Responda
-
it discards the frame without sending an error message to the network layer.
-
it discards the frame and sends an error message to the network layer.
-
it sends a NACK (not acknowledged frame) to the sending host.
-
it delivers the frame to the network layer, and lets the network layer decide what to do
Questão 61
Questão
A beacon frame sent by an AP includes
Questão 62
Questão
Packets sent by two stations in 802.11 can collide because
Responda
-
at a given time, the random backoff values of the two stations are the same.
-
the packets are sent to different APs but on the same channel.
-
the two stations could be hidden from each other.
-
all of the above
Questão 63
Questão
An 802.11 frame includes
Questão 64
Questão
Which of the following statements best describes the purpose of the SNMP protocol?
Responda
-
The SNMP protocol specifies the actions a network manager should take in response to a specific set of network fault conditions.
-
The SNMP protocol is a tool for gathering data about network conditions and executing remote actions at remote managed devices.
-
The SNMP protocol is used by the network manager to provision resources, such as bandwidth, server capacity and other computational/communication resources needed to meet the mission-specific needs of an enterprise
Questão 65
Questão
What is the purpose of the SNMP SetRequest message?
Responda
-
To allow a managed device to request and receive a set of initial values for MIB objects in the managed device.
-
To allow a managing entity to query the value of a set of MIB object values in a managed device.
-
To allow a managing entity to set the value of one or more MIB objects in a managed device
Questão 66
Questão
What is the purpose of a presentation service?
Responda
-
To allow a client to inform a server that it (the client) is present and ready to receive data.
-
To encode, transmit, and translate data from one machine-specific format to another.
-
To display data in a format specified by a user.
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None of the above
Questão 67
Questão
Filtering in a firewall can be based on:
Questão 68
Questão
How we call the link-layer packets?
Responda
-
Frames
-
Packets
-
Datagrams
-
Segment
-
Message
Questão 69
Questão
What is the segment?
Responda
-
application-layer packet
-
network-layer packet
-
data-link-layer packet
-
transport-layer packet
-
physical-layer packet
Questão 70
Questão
Most packets use these as the inputs to the links. This means that the packet switch must receive the entire packet before it can begin to transmit the first bit of the packet onto the outbound link
Responda
-
Queuing delays
-
Store-and-forward
-
Reliable data
-
Datagram
Questão 71
Questão
The housing a large number of hosts, is often used to create a powerful virtual server
Responda
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Supercomputer
-
Data center
-
Server house
-
Host center
Questão 72
Questão
Match the following delays to the correct definition
Responda
-
Processing delay
The time required to examine the packet’s header and determine where to direct the packet
-
Queuing delay
Packet waits to be transmitted onto the link
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Transmission delay
This is the amount of time required to push all of the packet’s bits into the link
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Propagation delay
Once a bit is pushed into the link, it needs to be spread to router
-
просто запомни ))))
Questão 73
Questão
________________ is a repository of information linked together from points all over the world
Questão 74
Questão
In a URL, the _______ is the full name of the file where the information is located
Questão 75
Questão
A cookie is made by the ________ and eaten by the _______
Responda
-
Client; client
-
Client; sever
-
Sever; server
-
None
Questão 76
Questão
In HTTP, the first line in a request message is called a _______ line; the first line in the response message is called the ________ line
Responda
-
Request; response
-
Response; request
-
Response; status
-
Header line; request
-
None
Questão 77
Questão
DNS provides a few other important service in addition to translating hostnames to IP addresses
Responda
-
Host aliasing
-
Delaying the packets
-
Congestion control
-
Load distribution
-
Mail server aliasing
Questão 78
Questão
Small piece of data sent from a website and stored in the user's web browser while the user is browsing
Responda
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Web cache
-
Set-cookies
-
Cookies
-
Status line
Questão 79
Questão
A network entity that satisfies HTTP requests on the behalf of an origin Web server
Responda
-
Web browser
-
Client
-
Root servers
-
Data center
-
Proxy server
-
DNS servers
Questão 80
Questão
How many ports can be per IP address
Responda
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65,535
-
68,535
-
65,335
-
64,535
-
60,535
Questão 81
Questão
FTP is built on _____ architecture
Responda
-
Client-server
-
P2P
-
Both of the mentioned
-
None
Questão 82
Questão
FTP uses _____ parallel TCP connections to transfer a file
Questão 83
Questão
If 5 files are transfered from server A to client B in the same session. The number of TCP connection between A and B is
Questão 84
Questão
The password is sent to the server using _____ command
Responda
-
PASSWD
-
PASS
-
PASSWORD
-
None
Questão 85
Questão
Time it takes for a small packet to travel from client to server and then back to the client
Questão 86
Questão
____________is a physical-layer device that acts on individual bits rather than frames
Responda
-
A hub
-
A host
-
Switch
-
Router
Questão 87
Questão
Define to which level of the network protocols are belong to
Responda
-
IMAP,POP3, DNS, FTP, Telnet-Application layer
-
TCP, UDP-Transport layer
-
ICMP, RIP, IPv4, IPv6-Network layer
-
ARP, ATM, Token ring-Data Link layer
-
Bluetooth, 802.11-Physical layer
-
ПРОСТО ЗАПОМНИ ВСЕ
Questão 88
Questão
___________algorithm computes the least-cost path between a source and destination using complete, global knowledge about the network
Responda
-
Virtual circuit
-
A global routing
-
Forwarding
-
None
Questão 89
Questão
Computer networks that provide only a connection service at the network layer are called
Responda
-
Datagram network
-
Virtual-circuit networks
-
Network
-
None
Questão 90
Questão
Each time an end system wants to send a packet, it stamps the packet with the address of the destination end system and then pops the packet into the network
Responda
-
Virtual-circuit networks
-
Network
-
Datagram network
-
None
Questão 91
Questão
Determine the correct class of the following IP address: 93.44.123.184
Questão 92
Questão
Determine the correct class of the following IP address: 160.23.244.224
Questão 93
Questão
Convert the following IP address: 192.224.224.15 to the binary
Responda
-
11000000. 11100000. 11100000. 00001111
-
11001100.11000111.11100011. 00001111
-
01010110. 01111011. 00000001. 00000001
-
11000100. 00000101. 01111011. 11011101
Questão 94
Questão
Convert the following IP address: 93.44.123.184 to the binary
Responda
-
11001100.11000111.11100011. 00001111
-
01010110. 01111011. 00000001. 00000001
-
11000100. 00000101. 01111011. 11011101
-
01011101. 00101100. 01111011. 10111000
Questão 95
Questão
Convert the following IP address: 158.0.147.85 to the binary
Responda
-
11001100.11000111.11100011. 00001111
-
01010110. 01111011. 00000001. 00000001
-
10011110. 00000000. 10010011. 01010101
-
11000100. 00000101. 01111011. 11011101
Questão 96
Questão
set of rules that the sending of rules that the sending program must follow so that the Internecan deliver the data to the destination program is called
Questão 97
Questão
Below provided a typical HTTP response message. Let’s take a careful look at this response message
What three sections has HTTP response message?
Responda
-
What three sections has HTTP response message?
-
header lines, entity body, and then the URL structure.
-
an initial status line, entity body, conclusion.
-
an initial status line, six header lines, and then the entity body.
-
header lines, entity body, and then the response
Questão 98
Questão
Below provided a typical HTTP response message. Let’s take a careful look at this response message. It has three sections:
an initial status line, six header lines, and then the entity body
The entity body is the meat of the message—it contains.
Responda
-
the information about receiver
-
the status line indicates that the server is using HTTP/1.1 and that everything is OK
-
the information about all the destination of packet
-
the requested object itself (represented by data data data data data)
Questão 99
Questão
Below provided a typical HTTP response message. Let’s take a careful look at this response message. It has three sections: an initial status line, six header lines, and then the entity body
In this example, the status line.
Responda
-
In this example, the status line.
-
has the information about receiver
-
has the requested object itself (represented by data data data data data …)
-
has the information about all the destination of packet
-
indicates that the server is using HTTP/1.1 and that everything is OK
Questão 100
Questão
How does an operating system identify the application to which data coming in from the network should be relayed
Responda
-
By the protocol with which the data was sent
-
Only one application at a time is given access to the network.
-
By the port number carried by the transport protocol
-
By the file extension of the data
Questão 101
Questão
The IP address space is organized in a hierarchy (I) to make the routing task more scalable, (II) to decrease inefficient fragmentation of the address space (III) to give institutions managing local-area networks autonomous control over the assignment of addresses to computers
Responda
-
I and III only
-
II only
-
none
-
I only
Questão 102
Questão
Which of the following protocols are essential to the existence of the Traceroute tool? 1 IP, 2 ICMP, 3 TCP
Responda
-
I and III only
-
II only
-
II and III only
-
I only
Questão 103
Questão
A difference between routers and switches is that
Responda
-
switches connect only to hosts, whereas routers connect networks
-
switches hold IP routing tables only for only local subnets
-
routers parse, process, and modify IP headers
-
routers perform the same function as switches but the two are marketed in very different way
Questão 104
Questão
At which of the following layers of the OSI protocol stack can the Internet Control Message Protocol be implement. 1Network, 2transport, 3Data link
Responda
-
I or II
-
I only
-
II only
-
III only
Questão 105
Questão
How to understand the connection-oriented protocol?
Responda
-
means that before the client and server can start to send data to each other, they first need to handshake and establish a TCP connection
-
means that provide an application with one or more security services can also provide timing guarantees
-
offers a different set of services to the invoking applications
Questão 106
Questão
Layers four and five of the Internet protocol stack are implemented in the end systems but not in the routers in the network core
Questão 107
Questão
Twisted-pair cooper wire is no longer present in computer networks
Questão 108
Questão
Two packets A and B are sent in that order through a connectionless communication network. They will arrive at the destination
Responda
-
in any order, after possibly having traversed different routes.
-
in the order A-B, after having traversed the same route.
-
in any order, after having traversed the same route.
-
in the order A-B, after possibly having traversed different routes
Questão 109
Questão
Compared to the wired transmission, wireless transmission typically has _____ attenuation and _____ maximum distance
Responda
-
higher, longer
-
lower, shorter
-
lower, longer
-
higher, shorter
Questão 110
Questão
Which of the following features of Ethernet has not remained constant since the advent of the technology?
Responda
-
Protocol header format
-
Protocol addressing
-
Use of CSMA-CD control
-
Transmission bandwidth
Questão 111
Questão
Which of the following internet applications typically transmit(s) packets over Transmission Control Protocol (TCP)? I.FTP client II.Audio streaming III.Web browser
Responda
-
I, II, and III
-
II only
-
I and II only
-
I and III only
Questão 112
Questão
In order to maintain network stability while Transmission Control Protocol (TCP) probes for additional bandwidth, rate increases are _____, and rate decreases are _____
Questão 113
Questão
Network clients use well-known _____ numbers to contact well-defined network services, such as Telnet and DNS servers
Responda
-
accept
-
connect
-
listen
-
port
Questão 114
Questão
Multicast communication generally refers to data that is
Responda
-
sent from several hosts to one host simultaneously
-
relayed through multiple routers
-
relayed through multiple bridges
-
sent from one host to several hosts simultaneously
Questão 115
Questão
The Internet Protocol (IP) defines the _____ layer of the Internet protocol stack
Responda
-
application
-
transport
-
physical
-
network
Questão 116
Questão
The term packetization refers to the process of
Responda
-
reassembling network packets for consumption by an application
-
using a digital instead of an analog transmission medium
-
using an analog instead of a digital transmission medium
-
splitting a message into fragments for network transmission
Questão 117
Questão
Which of the following statements is (are) true of network protocols?\n I.A protocol is a set of rules that facilitate communication among network applications.\n II.Only a single protocol may govern any transmission
Responda
-
II only
-
I and II
-
None
-
I only
Questão 118
Questão
Which of the following is a protocol used for communication between a web server and a web browser?
Responda
-
FTP
-
Telnet
-
World Wide Web (www)
-
HTTP
Questão 119
Questão
Which of the following is a disadvantage of connection-based protocols?
Responda
-
Unreliable connections
-
High error rates
-
Small MTU sizes
-
High startup costs
Questão 120
Questão
On a network, the term authentication typically refers to the process of
Responda
-
ensuring that users remain anonymous
-
ensuring that packets sent through the Internet cannot be intercepted
-
computing the checksum of packets
-
verifying the identity of a sender or receiver
Questão 121
Questão
Which of the following is the network-layer protocol of the Internet?
Questão 122
Questão
Which of the following was designed to solve the problem of IP address space fragmentation?
Questão 123
Questão
Which of the following IP header fields provide simple error detection?
Responda
-
Fragmentation
-
Time to live
-
Type of service
-
Checksum
Questão 124
Questão
Which of the following maps IP addresses onto datalink addresses?
Responda
-
Domain Name System (DNS)
-
Simple Network Management Protocol (SNMP)
-
Classless Inter Domain Routing (CIDR)
-
Address Resolution Protocol (ARP)
Questão 125
Questão
Consider an application running on host cs.cmu.edu that wants to send a packet to host ee.cmu.edu. Assuming no information is cached, the send request on cs.cmu.edu will cause which of the following events to happen first?
Questão 126
Questão
Which of the following can be used by a router to report a dropped packet to the packet's sender?
Responda
-
Simple Network Management Protocol (SNMP)
-
Border Gateway Protocol (BGP)
-
Dynamic Host Configuration Protocol (DHCP)
-
Internet Control Message Protocol (ICMP)
Questão 127
Questão
Which of the following IP header fields is designed to prevent a packet from remaining indefinitely in a routing loop?
Responda
-
Checksum
-
Length
-
Fragmentation
-
Time to live
Questão 128
Questão
Which of the following allows a host to be assigned an IP address automatically?
Responda
-
The simple network management protocol (SNMP)
-
The domain name system (DNS)
-
The address resolution protocol (ARP)
-
The dynamic host configuration protocol (DHCP)
Questão 129
Questão
Which of the following network exploration tools can be used to determine information about possible paths between one network host and another?
Responda
-
Ping
-
Netstat
-
Nslookup
-
Traceroute
Questão 130
Questão
The time required to examine the packet's header and determine where to direct the packet is part of the
Responda
-
Processing delay
-
Queuing delay
-
Transmission delay
-
Propagation delay
Questão 131
Questão
How we call the delay, when packet waits to be transmitted onto the link
Responda
-
Processing delay
-
Queuing delay
-
Transmission delay
-
Propagation delay
Questão 132
Questão
This is the amount of time required to push all of the packet's bits into the link
Responda
-
Processing delay
-
Queuing delay
-
Transmission delay
-
Propagation delay
Questão 133
Questão
The protocols of the various layers are called ___________
Responda
-
protocol stack
-
protocol layers
-
protocol group
-
protocol models
Questão 134
Questão
Which of the following OSI layers converts the ones and zeroes to electrical signals and places these signals on the cable?
Responda
-
Physical layer
-
Transport layer
-
Network layer
-
Application laye
Questão 135
Questão
Which of the following is most likely to be a MAC address assigned to a NIC?
Responda
-
192.168.1.121
-
24.17.232.75
-
23.4F.17.8A.4C.10
-
713.555.1212
Questão 136
Questão
Which layer of the TCP/IP model involves routing?
Responda
-
Physical layer
-
Transport layer
-
Application layer
-
Network layer
Questão 137
Questão
How much data can a typical frame contain?
Responda
-
500 bytes
-
1500 bytes
-
1500 bits
-
1 megabyte
Questão 138
Questão
Which of the following best describes an IP address?
Responda
-
A unique dotted decimal notation burned into every NIC
-
A unique 48-bit identifying number burned into every NIC
-
A dotted decimal notation assigned to a NIC by software
-
A 48-bit identifying number assigned to a NIC by software
Questão 139
Questão
Andalyn says complete 48-bit MAC addresses are allocated to NIC manufacturers from the IEEE. Buster says the IEEE only assigns the first 24 bits to manufacturers. Carlos says the IEEE assigns only the last 24 bits to manufacturers. Who is correct?
Responda
-
Only Andalyn is correct.
-
Only Buster is correct.
-
Only Carlos is correct.
-
No one is correct
Questão 140
Questão
Host A is sending host B a large file over a TCP connection. Assume host B has no data to send to A. Host B will not send acknowledgements to host A because host B cannot piggyback the acknowledgement on data
Questão 141
Questão
A channel partitioning protocol has which of the following characteristics
Questão 142
Questão
Ethernet provides which of the following services to the network layer
Questão 143
Questão
Each LAN adapter has a unique LAN address
Questão 144
Questão
A channel partitioning has which of the following characteristics
Questão 145
Questão
IEEE standard ethernet CSMA/CD provides which of the following services to the network layer?
Responda
-
reliable data transfer
-
error detection
-
error correction
-
all
Questão 146
Questão
Before sending a packet into a datagram network, the source must determine all of the links that packet will traverse between source and destination
Questão 147
Questão
The Session layer communicates with which other layers
Responda
-
Application and Transport
-
Transport and Network
-
Transport and Presentation
-
Transport, Presentation and Network
Questão 148
Questão
application layer data is
Responda
-
message
-
frame
-
datagram
-
data
-
segment
Questão 149
Questão
Transport layer data is
Responda
-
message
-
frame
-
data
-
datagram
-
segment
Questão 150
Questão
Network layer data is
Responda
-
message
-
frame
-
datagram
-
segment
-
data
Questão 151
Questão
Link layer data is
Responda
-
message
-
frame
-
datagram
-
data
-
segment
Questão 152
Questão
HTTP persistent connection - multiple objects can be sent over single TCP connection between client, server
Questão 153
Questão
HTTP non- persistent connection - multiple objects can be sent over single TCP connection between client, server
Questão 154
Responda
-
to transfer messages from one mail server to another
-
to transfer messages from one mail server to another user agent
-
to define the format of message headers
-
to transfer messages from one user to another
Questão 155
Questão
The transmission of high-quality, interactive voice and video over the current Internet is difficult because today's Internet
Responda
-
does not really have sufficient throughput
-
gives higher priority to bulk data transfers
-
uses connectionless protocols
-
is unable to guarantee minimum throughput or maximum latency for a given connection
Questão 156
Questão
The throughput of a network link for an HTTP session is measured in two ways. Measurement A is the total amount of data received by the browser, divided by the duration of the session. Measurement B is the total amount of data received by the operating system on behalf of the browser, divided by the duration of the session. Which of the following statements about A and B is true?
Responda
-
B is smaller than A
-
A is smaller than B
-
B is equal to A
-
B and A are not related
Questão 157
Questão
Ethernet (IEEE 802.3) is an example of
Responda
-
a standard developed by the International Telecommunications Union
-
a successful example of the Internet's strategy of developing standards through "rough consensus and running code"
-
a de facto standard later developed into a de jure standard
-
an a priori standard
Questão 158
Questão
A packet with no data is sent from host A to host B on an otherwise idle network. The packet is found to have taken 35 milliseconds to reach B. The incremental overhead to send an additional byte (usually called the "throughput") is estimated to be five microseconds by repeatedly measuring the transmission times of long packets. Approximately, how long will an eight Kbytes (8192 bytes) packet take to reach B when sent from A?
Questão 159
Questão
When the data link layer applies "framing" to the data to be transmitted, it
Responda
-
cuts out the headers from higher layer protocols before transmission
-
adds the protocol headers from higher layers to the data before it transmits it
-
inserts flags to draw attention to high-priority data within a transmission
-
enhances it with extra data that permits the receiver to synchronize with the sender
Questão 160
Questão
In a broadcast-based network, longer propagation delays
Responda
-
destroy the carrier, making it impossible to sense it before transmitting
-
make it all the more critical to sense the carrier before transmitting
-
significantly decrease the benefit of sensing the carrier before transmitting
-
do not affect the cost-benefit trade-off of carrier sensing
Questão 161
Questão
What is the type of an "8+1" parity code that outputs 100101011?
Questão 162
Questão
A specific CSMA-CD network such as 10-BASET "Ethernet
Responda
-
has higher cost per node as nodes are added
-
can connect very distant node
-
works best for an even number of nodes
-
suffers performance degradation as nodes are added
Questão 163
Questão
A university has 20 computers in a laboratory that is currently served by several small 10 Base-T "Ethernet" hubs that are directly connected to each other. The network performance has been found to be lacking, and an upgrade is planned. The computers are identical and place a comparable load on the network that is relatively constant and modest for each computer (in the order of 500 Kbps). What would you suggest for the upgrade?
Responda
-
A small 10 Base-T switch to connect the existing hub
-
Replace the hubs with 100 Base-T hub
-
A new bank of dial-up modems
-
Replace the hubs with 10 Base-T switches
Questão 164
Questão
A sender's data link layer uses "bit stuffing" to
Responda
-
force the receiver to enlarge its flow control window
-
avoid confusing data bits with control bits
-
pad the data so that it has an even length for parity calculations
-
mark the start and the end of a frame
Questão 165
Questão
The Internet Protocol (IP) is used in the network layer of the Internet. Which service does IP provide to the transport layer?
Responda
-
Connectionless service via virtual circuits
-
Connectionless service via datagrams
-
Connection-oriented service via datagrams
-
Connection-oriented service via virtual circuits
Questão 166
Questão
A corporate information systems manager is interested in collecting statistics on the frequency of computer failures within the organization. Most failures result in an automatic reboot, so the failed computer is typically back on the network in less than a minute. The corporate network connects 1,500 computers in far-flung locations to which the average latency of a packet is 40 milliseconds. The manager asks you to write a tool that will collect the times at which failures occurred in which computers. She wants it by tomorrow, so the tool will have to be simple. On which protocol will you base your implementation?
Questão 167
Questão
A router is installed to interconnect 4 subnetworks with MTUs of 1024, 2048, 576, and 1556 bytes respectively. Nodes A and B are connected to the first and second subnets, respectively. An application on node A sends a 4096-byte datagram (e.g., using UDP) to an application on node B. How many IP fragments will the router process as a result?
Questão 168
Questão
The network interface card of a Web server that you manage has developed sporadic problems. You measure the packet loss rate from your desktop computer and immediately decide to replace the network card. After this simple operation, the Web server successfully rejoins the network, as confirmed by your officemate using her desktop computer. You eagerly go to your desktop to measure the improvement, but find instead that the Web server is not responding to any of your packets. What is your diagnosis?
Responda
-
The new network card does not work.
-
Your desktop computer is still trying to contact the server's old network card.
-
Your desktop computer's network card does not work.
-
The Domain Name System (DNS) has not yet updated its entry for the Web server.
Questão 169
Questão
In contrast to standards developed by traditional standards organizations like the International
Telecommunications Union (ITU) or the International Standards Organization (ISO), standards developed by the Internet Engineering Task Force (IETF) can be
Responda
-
developed in secret by the members of the IETF until the standards mature sufficiently to withstand public criticism
-
modified arbitrarily by the Advance Research projects Agency (ARPA) of the United States Department of Defense, which originally developed the Internet
-
applied before they have been embodied in working implementations, in order not to delay progress
-
extensively critiqued and modified by individuals, without requiring them to have special membership status
Questão 170
Questão
there are transport service requirements, for which of the following applications these requirements are demanded: no data loss, elastic throughput, and not time sensitive
Responda
-
e-mail
-
real time audio/video
-
text messaging
-
games
Questão 171
Questão
there are transport service requirements, for which of the following applications these requirements are demanded: no data loss, elastic throughput, and not time sensitive
Responda
-
web documents
-
real time audio/video
-
text messaging
-
games
Questão 172
Questão
reliable transport between sending and receiving process refers to (protocol type)?
Questão 173
Questão
TP client contacts FTP server at port ______, using TCP
Questão 174
Questão
331 Username OK, password required – status code refers to (protocol type)?
Questão 175
Questão
e-mails use ______________ protocol for sending messages
Questão 176
Questão 177
Questão 178
Questão
Which of the following statements are true about the TCP service model?
Responda
-
TCP uses a checksum to determine if the application data follows the right syntax
-
TCP delivers a stream of bytes from one end to the other, reliably and in-sequence, on behalf of an application
-
Because TCP encodes data with enough information to correct errors, it never needs to retransmit missing segments
-
Because TCP cannot trust the IP layer to format packets correctly, it must include the destination IP address in the TCP header
-
TCP is responsible for providing reliable, in-sequence end-to-end delivery of data between applications.
Questão 179
Questão
Which of the following are direct consequences of this design choice?
Responda
-
TCP is self-contained with sufficient addressing information in its header that it does not need the IP layer, or any other layer beneath it to deliver data to the far end
-
TCP will retransmit missing data even if the application can not use it - for example, in Internet telephony a late arriving retransmission may arrive too late to be useful
-
TCP can only work correctly if the layer below it also delivers data reliably and in sequence
-
TCP requires no connection state to be established prior to the end points communicating
Questão 180
Questão
The _______ layer lies between the network layer and the application layer.
Responda
-
physical
-
data link
-
transport
-
none
Questão 181
Questão
Which of the following is an application layer service?
Responda
-
remote log-in
-
mail service
-
file transfer and access
-
all
Questão 182
Questão
The_________ layer is responsible for the delivery of a message from one process to another
Responda
-
physical
-
data link
-
transport
-
network
Questão 183
Questão
The Internetworking Protocol (IP) is a ________ protocol
Responda
-
reliable
-
connectionless
-
connection oriented
-
none
Questão 184
Questão
____ is a process-to-process protocol that adds only port addresses, checksum error control, and length information to the data from the upper layer
Questão 185
Questão
__________provides full transport layer services to applications
Questão 186
Questão
Translation of a domain name into an address called
Questão 187
Questão
In a link layer hosts and router are called
Responda
-
Node
-
Frame
-
Protocol
-
Server
Questão 188
Questão
Link layer encapsulates datagrad in a
Responda
-
Node
-
Frame
-
Protocol
-
Server
Questão 189
Questão
The FDDI protocol is based on
Questão 190
Questão
Registered users may look up all meetings in their agenda in a given interval of time
Responda
-
Querying Meetings
-
User Registration
-
Adding Meetings
-
Deleting Meetings
-
Clearing Meetings
Questão 191
Questão
Dividing the network into smaller portions called
Responda
-
Subnet
-
Subnet Mask
-
Bits
-
IP
Questão 192
Questão
Identify the incorrect statement
Responda
-
FTP sends its control information in-band
-
FTP stands for File Transfer Protocol
-
FTP uses two parallel TCP connections
-
FTP sends exactly one file over the data connection
Questão 193
Questão
Find the FTP reply whose message is wrongly matched
Responda
-
331 – Username OK, password required
-
425 – Can’t open data connection
-
452 – Error writing file
-
452 – Can’t open data connection
Questão 194
Questão
Typically the TCP port used by SMTP is
Questão 195
Questão
The entire hostname has a maximum of ___characters
Questão 196
Questão
Which one of the following allows a user at one site to establish a connection to another site and then pass keystrokes from local host to remote host?
Questão 197
Questão
All link layer protocols that support IP have the same frame structure (i.e., length of frame, number and length of header fields).
Questão 198
Questão
Suppose a network manager wanted to query the value of the number of TCP segments received by a host running the Microsoft Windows 2000 operating system in a US-based company. What would be the prefix (leading digits) of the MIB variable that should be queried?
Questão 199
Questão
For public-key certification, PGP uses certification authorities.
Questão 200
Questão
The 802.11 protocol does not implement collision detection because
Responda
-
the adapter would still not be able to detect all collisions due to hidden terminals.
-
it is costly to build wireless hardware that detects collisions.
-
collision detection was found to be useless in wired Ethernet.
-
all of the above