Pregunta 1
Pregunta
In version field of IPv4 header, when machine is using some other version of IPv4 then datagram is
Respuesta
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Rejected
-
Accepted
-
Interpreted
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Interpreted incorrectly
Pregunta 2
Pregunta
Network layer at source is responsible for creating a packet from data coming from another
Respuesta
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Station
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Link
-
Node
-
Protocol
Pregunta 3
Pregunta
Header of datagram in IPv4 has
Respuesta
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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
Pregunta 4
Pregunta
An IPv4 datagram can encapsulate data from several higher-level protocols such as UDP, ICMP, IGMP and
Respuesta
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TCP protocols
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CDM protocols
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ATM protocols
-
IEEE protocols
Pregunta 5
Pregunta
To record Internet routers of IPv4, that handles datagram is responsibility of
Respuesta
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Record protocol
-
Record Data
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Record Route
-
Record Header
Pregunta 6
Pregunta
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
Pregunta 7
Pregunta
In IPv4 protocol, each datagram is handled
Respuesta
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Independently
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Dependently
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Priority basis
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Systematically
Pregunta 8
Respuesta
-
Close Circuit Transmission
-
Congestion Controlled Traffic
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Congestion Controlled Transmission
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Close Circuit Traffic
Pregunta 9
Pregunta
Communication between a computer and a keyboard involves ______________ transmission
Respuesta
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Automatic
-
Half-duplex
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Full-duplex
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Single direction
Pregunta 10
Pregunta
Three or more devices share a link in ________ connection
Respuesta
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Unipoint
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Multipoint
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Point to point
-
None
Pregunta 11
Pregunta
In asynchronous serial communication the physical layer provide
Pregunta 12
Pregunta
The physical layer is responsible for
Respuesta
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line coding
-
channel coding
-
modulation
-
all of the mentioned
Pregunta 13
Pregunta
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
Pregunta 14
Pregunta
Wireless transmission can be done via
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radio waves
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microwaves
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infrared
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all of the mentioned
Pregunta 15
Pregunta
Which is not a application layer protocol?
Pregunta 16
Pregunta
The packet of information at the application layer is called __________
Respuesta
-
Packet
-
Message
-
Segment
-
Frame
Pregunta 17
Pregunta
Which one of the following is an architecture paradigms?
Pregunta 18
Pregunta
Application layer offers _______ service
Pregunta 19
Pregunta
E-mail is _________
Pregunta 20
Pregunta
To deliver a message to the correct application program running on a host, the _______ address must be consulted
Pregunta 21
Pregunta
Layers four and five of the Internet protocol stack are implemented in the end systems but not in the routers in the network core
Pregunta 22
Pregunta
With ADSL, each subscriber gets more downstream bandwidth than upstream bandwidth
Pregunta 23
Pregunta
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.
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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.
Pregunta 24
Pregunta
Two packets A and B are sent in that order through a connectionless communication network. They will arrive at the destination:
Respuesta
-
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
Pregunta 25
Pregunta
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.
-
it achieved international scope with the addition of the City University of London.
Pregunta 26
Pregunta
All store-and-forward networks are
Pregunta 27
Pregunta
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.
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Space-switched.
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Circuit-switched
Pregunta 28
Pregunta
The Date: header in the HTTP response message indicates when the object in the response was last modified.
Pregunta 29
Pregunta
The process that sends messages into, and receives messages from, the network through a software interface is called a socket.
Pregunta 30
Pregunta
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.
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none of the above
Pregunta 31
Pregunta
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
Pregunta 32
Pregunta
SMTP is used to:
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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.
Pregunta 33
Pregunta
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.
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none of the above.
Pregunta 34
Pregunta
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.
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never cache resource records
Pregunta 35
Pregunta
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.
Pregunta 36
Pregunta
The size of the TCP RcvWindow never changes throughout the duration of the connection
Pregunta 37
Pregunta
The TCP segment has a field in its header for RcvWindow
Pregunta 38
Pregunta
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
Pregunta 39
Pregunta
The MSS is the maximum size of a TCP segment including headers
Pregunta 40
Pregunta
When a TCP segment arrives to a host, the socket to which the segment is directed depends on
Pregunta 41
Pregunta
UDP has which of the following characteristics
Pregunta 42
Pregunta
When a UDP segment arrives to a host, in order to direct the segment to the appropriate socket, the OS uses
Pregunta 43
Pregunta
The stop-and-wait protocol is highly inefficient when there is a
Respuesta
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large distance between source and destination and the transmission rate is low
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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
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short distance between source and destination and the transmission rate is low
Pregunta 44
Pregunta
Pipelining requires which of the following
Respuesta
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transmitting many packets before receiving acknowledgements
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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
Pregunta 45
Pregunta
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
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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
Pregunta 46
Pregunta
Streams are not needed in which of the following programs
Respuesta
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TCPserver
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UDPserver
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TCPclient
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UDPclient
Pregunta 47
Pregunta
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.
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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
Pregunta 48
Pregunta
Consider the latency model for dynamic congestion windows. Which of the following components contribute to latency?
Pregunta 49
Pregunta
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
Pregunta 50
Pregunta
Nmap is often used to
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do port scans over a range of ports at a target host
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measure throughput between hosts
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measure round-trip times between hosts
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decipher encrypted traffic
Pregunta 51
Pregunta
With SYN cookies, when a server receives a SYN segment, it returns a SYNACK with
Respuesta
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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)
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initial sequence number 1
-
a randomly chosen initial sequence number
-
none of the above
Pregunta 52
Pregunta
Before sending a packet into a datagram network, the source must determine all of the links that packet will traverse between source and destination
Pregunta 53
Pregunta
The primary role of a router is to forward datagrams from input links to output links
Pregunta 54
Pregunta
A forwarding table is
Respuesta
-
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
Pregunta 55
Pregunta
How are routing paths calculated?
Respuesta
-
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.
-
The path is calculated based on available network bandwidth
Pregunta 56
Pregunta
A channel partitioning protocol has which of the following characteristics forwarding table is
Pregunta 57
Pregunta
Match the following network service to the correct definition
Respuesta
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Guaranteed Delivery - Guarantees a packet will arrive at its destination
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Guaranteed Delivery with Bounded Delay- Guarantees delivery within a specified host-to-host delay bound
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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
Pregunta 58
Pregunta
An ARP query packet is encapsulated in an IP datagram.
Pregunta 59
Pregunta
Ethernet provides which of the following services to the network layer
error detection
Respuesta
-
error detection
-
flow control
-
reliable data transfer
-
all of the above
Pregunta 60
Pregunta
For Ethernet, if an adapter determines that a frame it has just received is addressed to a different adapter
Respuesta
-
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
Pregunta 61
Pregunta
A beacon frame sent by an AP includes
Pregunta 62
Pregunta
Packets sent by two stations in 802.11 can collide because
Respuesta
-
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
Pregunta 63
Pregunta
An 802.11 frame includes
Pregunta 64
Pregunta
Which of the following statements best describes the purpose of the SNMP protocol?
Respuesta
-
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
Pregunta 65
Pregunta
What is the purpose of the SNMP SetRequest message?
Respuesta
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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
Pregunta 66
Pregunta
What is the purpose of a presentation service?
Respuesta
-
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
Pregunta 67
Pregunta
Filtering in a firewall can be based on:
Pregunta 68
Pregunta
How we call the link-layer packets?
Respuesta
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Frames
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Packets
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Datagrams
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Segment
-
Message
Pregunta 69
Pregunta
What is the segment?
Respuesta
-
application-layer packet
-
network-layer packet
-
data-link-layer packet
-
transport-layer packet
-
physical-layer packet
Pregunta 70
Pregunta
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
Respuesta
-
Queuing delays
-
Store-and-forward
-
Reliable data
-
Datagram
Pregunta 71
Pregunta
The housing a large number of hosts, is often used to create a powerful virtual server
Respuesta
-
Supercomputer
-
Data center
-
Server house
-
Host center
Pregunta 72
Pregunta
Match the following delays to the correct definition
Respuesta
-
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
-
Transmission delay
This is the amount of time required to push all of the packet’s bits into the link
-
Propagation delay
Once a bit is pushed into the link, it needs to be spread to router
-
просто запомни ))))
Pregunta 73
Pregunta
________________ is a repository of information linked together from points all over the world
Pregunta 74
Pregunta
In a URL, the _______ is the full name of the file where the information is located
Pregunta 75
Pregunta
A cookie is made by the ________ and eaten by the _______
Respuesta
-
Client; client
-
Client; sever
-
Sever; server
-
None
Pregunta 76
Pregunta
In HTTP, the first line in a request message is called a _______ line; the first line in the response message is called the ________ line
Respuesta
-
Request; response
-
Response; request
-
Response; status
-
Header line; request
-
None
Pregunta 77
Pregunta
DNS provides a few other important service in addition to translating hostnames to IP addresses
Respuesta
-
Host aliasing
-
Delaying the packets
-
Congestion control
-
Load distribution
-
Mail server aliasing
Pregunta 78
Pregunta
Small piece of data sent from a website and stored in the user's web browser while the user is browsing
Respuesta
-
Web cache
-
Set-cookies
-
Cookies
-
Status line
Pregunta 79
Pregunta
A network entity that satisfies HTTP requests on the behalf of an origin Web server
Respuesta
-
Web browser
-
Client
-
Root servers
-
Data center
-
Proxy server
-
DNS servers
Pregunta 80
Pregunta
How many ports can be per IP address
Respuesta
-
65,535
-
68,535
-
65,335
-
64,535
-
60,535
Pregunta 81
Pregunta
FTP is built on _____ architecture
Respuesta
-
Client-server
-
P2P
-
Both of the mentioned
-
None
Pregunta 82
Pregunta
FTP uses _____ parallel TCP connections to transfer a file
Pregunta 83
Pregunta
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
Pregunta 84
Pregunta
The password is sent to the server using _____ command
Respuesta
-
PASSWD
-
PASS
-
PASSWORD
-
None
Pregunta 85
Pregunta
Time it takes for a small packet to travel from client to server and then back to the client
Pregunta 86
Pregunta
____________is a physical-layer device that acts on individual bits rather than frames
Respuesta
-
A hub
-
A host
-
Switch
-
Router
Pregunta 87
Pregunta
Define to which level of the network protocols are belong to
Respuesta
-
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
Pregunta 88
Pregunta
___________algorithm computes the least-cost path between a source and destination using complete, global knowledge about the network
Respuesta
-
Virtual circuit
-
A global routing
-
Forwarding
-
None
Pregunta 89
Pregunta
Computer networks that provide only a connection service at the network layer are called
Respuesta
-
Datagram network
-
Virtual-circuit networks
-
Network
-
None
Pregunta 90
Pregunta
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
Respuesta
-
Virtual-circuit networks
-
Network
-
Datagram network
-
None
Pregunta 91
Pregunta
Determine the correct class of the following IP address: 93.44.123.184
Pregunta 92
Pregunta
Determine the correct class of the following IP address: 160.23.244.224
Pregunta 93
Pregunta
Convert the following IP address: 192.224.224.15 to the binary
Respuesta
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11000000. 11100000. 11100000. 00001111
-
11001100.11000111.11100011. 00001111
-
01010110. 01111011. 00000001. 00000001
-
11000100. 00000101. 01111011. 11011101
Pregunta 94
Pregunta
Convert the following IP address: 93.44.123.184 to the binary
Respuesta
-
11001100.11000111.11100011. 00001111
-
01010110. 01111011. 00000001. 00000001
-
11000100. 00000101. 01111011. 11011101
-
01011101. 00101100. 01111011. 10111000
Pregunta 95
Pregunta
Convert the following IP address: 158.0.147.85 to the binary
Respuesta
-
11001100.11000111.11100011. 00001111
-
01010110. 01111011. 00000001. 00000001
-
10011110. 00000000. 10010011. 01010101
-
11000100. 00000101. 01111011. 11011101
Pregunta 96
Pregunta
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
Pregunta 97
Pregunta
Below provided a typical HTTP response message. Let’s take a careful look at this response message
What three sections has HTTP response message?
Respuesta
-
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
Pregunta 98
Pregunta
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.
Respuesta
-
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)
Pregunta 99
Pregunta
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.
Respuesta
-
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
Pregunta 100
Pregunta
How does an operating system identify the application to which data coming in from the network should be relayed
Respuesta
-
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
Pregunta 101
Pregunta
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
Respuesta
-
I and III only
-
II only
-
none
-
I only
Pregunta 102
Pregunta
Which of the following protocols are essential to the existence of the Traceroute tool? 1 IP, 2 ICMP, 3 TCP
Respuesta
-
I and III only
-
II only
-
II and III only
-
I only
Pregunta 103
Pregunta
A difference between routers and switches is that
Respuesta
-
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
Pregunta 104
Pregunta
At which of the following layers of the OSI protocol stack can the Internet Control Message Protocol be implement. 1Network, 2transport, 3Data link
Respuesta
-
I or II
-
I only
-
II only
-
III only
Pregunta 105
Pregunta
How to understand the connection-oriented protocol?
Respuesta
-
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
Pregunta 106
Pregunta
Layers four and five of the Internet protocol stack are implemented in the end systems but not in the routers in the network core
Pregunta 107
Pregunta
Twisted-pair cooper wire is no longer present in computer networks
Pregunta 108
Pregunta
Two packets A and B are sent in that order through a connectionless communication network. They will arrive at the destination
Respuesta
-
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
Pregunta 109
Pregunta
Compared to the wired transmission, wireless transmission typically has _____ attenuation and _____ maximum distance
Respuesta
-
higher, longer
-
lower, shorter
-
lower, longer
-
higher, shorter
Pregunta 110
Pregunta
Which of the following features of Ethernet has not remained constant since the advent of the technology?
Respuesta
-
Protocol header format
-
Protocol addressing
-
Use of CSMA-CD control
-
Transmission bandwidth
Pregunta 111
Pregunta
Which of the following internet applications typically transmit(s) packets over Transmission Control Protocol (TCP)? I.FTP client II.Audio streaming III.Web browser
Respuesta
-
I, II, and III
-
II only
-
I and II only
-
I and III only
Pregunta 112
Pregunta
In order to maintain network stability while Transmission Control Protocol (TCP) probes for additional bandwidth, rate increases are _____, and rate decreases are _____
Pregunta 113
Pregunta
Network clients use well-known _____ numbers to contact well-defined network services, such as Telnet and DNS servers
Respuesta
-
accept
-
connect
-
listen
-
port
Pregunta 114
Pregunta
Multicast communication generally refers to data that is
Respuesta
-
sent from several hosts to one host simultaneously
-
relayed through multiple routers
-
relayed through multiple bridges
-
sent from one host to several hosts simultaneously
Pregunta 115
Pregunta
The Internet Protocol (IP) defines the _____ layer of the Internet protocol stack
Respuesta
-
application
-
transport
-
physical
-
network
Pregunta 116
Pregunta
The term packetization refers to the process of
Respuesta
-
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
Pregunta 117
Pregunta
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
Respuesta
-
II only
-
I and II
-
None
-
I only
Pregunta 118
Pregunta
Which of the following is a protocol used for communication between a web server and a web browser?
Respuesta
-
FTP
-
Telnet
-
World Wide Web (www)
-
HTTP
Pregunta 119
Pregunta
Which of the following is a disadvantage of connection-based protocols?
Respuesta
-
Unreliable connections
-
High error rates
-
Small MTU sizes
-
High startup costs
Pregunta 120
Pregunta
On a network, the term authentication typically refers to the process of
Respuesta
-
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
Pregunta 121
Pregunta
Which of the following is the network-layer protocol of the Internet?
Pregunta 122
Pregunta
Which of the following was designed to solve the problem of IP address space fragmentation?
Pregunta 123
Pregunta
Which of the following IP header fields provide simple error detection?
Respuesta
-
Fragmentation
-
Time to live
-
Type of service
-
Checksum
Pregunta 124
Pregunta
Which of the following maps IP addresses onto datalink addresses?
Respuesta
-
Domain Name System (DNS)
-
Simple Network Management Protocol (SNMP)
-
Classless Inter Domain Routing (CIDR)
-
Address Resolution Protocol (ARP)
Pregunta 125
Pregunta
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?
Pregunta 126
Pregunta
Which of the following can be used by a router to report a dropped packet to the packet's sender?
Respuesta
-
Simple Network Management Protocol (SNMP)
-
Border Gateway Protocol (BGP)
-
Dynamic Host Configuration Protocol (DHCP)
-
Internet Control Message Protocol (ICMP)
Pregunta 127
Pregunta
Which of the following IP header fields is designed to prevent a packet from remaining indefinitely in a routing loop?
Respuesta
-
Checksum
-
Length
-
Fragmentation
-
Time to live
Pregunta 128
Pregunta
Which of the following allows a host to be assigned an IP address automatically?
Respuesta
-
The simple network management protocol (SNMP)
-
The domain name system (DNS)
-
The address resolution protocol (ARP)
-
The dynamic host configuration protocol (DHCP)
Pregunta 129
Pregunta
Which of the following network exploration tools can be used to determine information about possible paths between one network host and another?
Respuesta
-
Ping
-
Netstat
-
Nslookup
-
Traceroute
Pregunta 130
Pregunta
The time required to examine the packet's header and determine where to direct the packet is part of the
Respuesta
-
Processing delay
-
Queuing delay
-
Transmission delay
-
Propagation delay
Pregunta 131
Pregunta
How we call the delay, when packet waits to be transmitted onto the link
Respuesta
-
Processing delay
-
Queuing delay
-
Transmission delay
-
Propagation delay
Pregunta 132
Pregunta
This is the amount of time required to push all of the packet's bits into the link
Respuesta
-
Processing delay
-
Queuing delay
-
Transmission delay
-
Propagation delay
Pregunta 133
Pregunta
The protocols of the various layers are called ___________
Respuesta
-
protocol stack
-
protocol layers
-
protocol group
-
protocol models
Pregunta 134
Pregunta
Which of the following OSI layers converts the ones and zeroes to electrical signals and places these signals on the cable?
Respuesta
-
Physical layer
-
Transport layer
-
Network layer
-
Application laye
Pregunta 135
Pregunta
Which of the following is most likely to be a MAC address assigned to a NIC?
Respuesta
-
192.168.1.121
-
24.17.232.75
-
23.4F.17.8A.4C.10
-
713.555.1212
Pregunta 136
Pregunta
Which layer of the TCP/IP model involves routing?
Respuesta
-
Physical layer
-
Transport layer
-
Application layer
-
Network layer
Pregunta 137
Pregunta
How much data can a typical frame contain?
Respuesta
-
500 bytes
-
1500 bytes
-
1500 bits
-
1 megabyte
Pregunta 138
Pregunta
Which of the following best describes an IP address?
Respuesta
-
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
Pregunta 139
Pregunta
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?
Respuesta
-
Only Andalyn is correct.
-
Only Buster is correct.
-
Only Carlos is correct.
-
No one is correct
Pregunta 140
Pregunta
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
Pregunta 141
Pregunta
A channel partitioning protocol has which of the following characteristics
Pregunta 142
Pregunta
Ethernet provides which of the following services to the network layer
Pregunta 143
Pregunta
Each LAN adapter has a unique LAN address
Pregunta 144
Pregunta
A channel partitioning has which of the following characteristics
Pregunta 145
Pregunta
IEEE standard ethernet CSMA/CD provides which of the following services to the network layer?
Respuesta
-
reliable data transfer
-
error detection
-
error correction
-
all
Pregunta 146
Pregunta
Before sending a packet into a datagram network, the source must determine all of the links that packet will traverse between source and destination
Pregunta 147
Pregunta
The Session layer communicates with which other layers
Respuesta
-
Application and Transport
-
Transport and Network
-
Transport and Presentation
-
Transport, Presentation and Network
Pregunta 148
Pregunta
application layer data is
Respuesta
-
message
-
frame
-
datagram
-
data
-
segment
Pregunta 149
Pregunta
Transport layer data is
Respuesta
-
message
-
frame
-
data
-
datagram
-
segment
Pregunta 150
Pregunta
Network layer data is
Respuesta
-
message
-
frame
-
datagram
-
segment
-
data
Pregunta 151
Pregunta
Link layer data is
Respuesta
-
message
-
frame
-
datagram
-
data
-
segment
Pregunta 152
Pregunta
HTTP persistent connection - multiple objects can be sent over single TCP connection between client, server
Pregunta 153
Pregunta
HTTP non- persistent connection - multiple objects can be sent over single TCP connection between client, server
Pregunta 154
Respuesta
-
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
Pregunta 155
Pregunta
The transmission of high-quality, interactive voice and video over the current Internet is difficult because today's Internet
Respuesta
-
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
Pregunta 156
Pregunta
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?
Respuesta
-
B is smaller than A
-
A is smaller than B
-
B is equal to A
-
B and A are not related
Pregunta 157
Pregunta
Ethernet (IEEE 802.3) is an example of
Respuesta
-
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
Pregunta 158
Pregunta
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?
Pregunta 159
Pregunta
When the data link layer applies "framing" to the data to be transmitted, it
Respuesta
-
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
Pregunta 160
Pregunta
In a broadcast-based network, longer propagation delays
Respuesta
-
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
Pregunta 161
Pregunta
What is the type of an "8+1" parity code that outputs 100101011?
Pregunta 162
Pregunta
A specific CSMA-CD network such as 10-BASET "Ethernet
Respuesta
-
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
Pregunta 163
Pregunta
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?
Respuesta
-
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
Pregunta 164
Pregunta
A sender's data link layer uses "bit stuffing" to
Respuesta
-
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
Pregunta 165
Pregunta
The Internet Protocol (IP) is used in the network layer of the Internet. Which service does IP provide to the transport layer?
Respuesta
-
Connectionless service via virtual circuits
-
Connectionless service via datagrams
-
Connection-oriented service via datagrams
-
Connection-oriented service via virtual circuits
Pregunta 166
Pregunta
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?
Pregunta 167
Pregunta
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?
Pregunta 168
Pregunta
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?
Respuesta
-
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.
Pregunta 169
Pregunta
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
Respuesta
-
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
Pregunta 170
Pregunta
there are transport service requirements, for which of the following applications these requirements are demanded: no data loss, elastic throughput, and not time sensitive
Respuesta
-
e-mail
-
real time audio/video
-
text messaging
-
games
Pregunta 171
Pregunta
there are transport service requirements, for which of the following applications these requirements are demanded: no data loss, elastic throughput, and not time sensitive
Respuesta
-
web documents
-
real time audio/video
-
text messaging
-
games
Pregunta 172
Pregunta
reliable transport between sending and receiving process refers to (protocol type)?
Pregunta 173
Pregunta
TP client contacts FTP server at port ______, using TCP
Pregunta 174
Pregunta
331 Username OK, password required – status code refers to (protocol type)?
Pregunta 175
Pregunta
e-mails use ______________ protocol for sending messages
Pregunta 176
Pregunta 177
Pregunta 178
Pregunta
Which of the following statements are true about the TCP service model?
Respuesta
-
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.
Pregunta 179
Pregunta
Which of the following are direct consequences of this design choice?
Respuesta
-
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
Pregunta 180
Pregunta
The _______ layer lies between the network layer and the application layer.
Respuesta
-
physical
-
data link
-
transport
-
none
Pregunta 181
Pregunta
Which of the following is an application layer service?
Respuesta
-
remote log-in
-
mail service
-
file transfer and access
-
all
Pregunta 182
Pregunta
The_________ layer is responsible for the delivery of a message from one process to another
Respuesta
-
physical
-
data link
-
transport
-
network
Pregunta 183
Pregunta
The Internetworking Protocol (IP) is a ________ protocol
Respuesta
-
reliable
-
connectionless
-
connection oriented
-
none
Pregunta 184
Pregunta
____ is a process-to-process protocol that adds only port addresses, checksum error control, and length information to the data from the upper layer
Pregunta 185
Pregunta
__________provides full transport layer services to applications
Pregunta 186
Pregunta
Translation of a domain name into an address called
Pregunta 187
Pregunta
In a link layer hosts and router are called
Respuesta
-
Node
-
Frame
-
Protocol
-
Server
Pregunta 188
Pregunta
Link layer encapsulates datagrad in a
Respuesta
-
Node
-
Frame
-
Protocol
-
Server
Pregunta 189
Pregunta
The FDDI protocol is based on
Pregunta 190
Pregunta
Registered users may look up all meetings in their agenda in a given interval of time
Respuesta
-
Querying Meetings
-
User Registration
-
Adding Meetings
-
Deleting Meetings
-
Clearing Meetings
Pregunta 191
Pregunta
Dividing the network into smaller portions called
Respuesta
-
Subnet
-
Subnet Mask
-
Bits
-
IP
Pregunta 192
Pregunta
Identify the incorrect statement
Respuesta
-
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
Pregunta 193
Pregunta
Find the FTP reply whose message is wrongly matched
Respuesta
-
331 – Username OK, password required
-
425 – Can’t open data connection
-
452 – Error writing file
-
452 – Can’t open data connection
Pregunta 194
Pregunta
Typically the TCP port used by SMTP is
Pregunta 195
Pregunta
The entire hostname has a maximum of ___characters
Pregunta 196
Pregunta
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?
Pregunta 197
Pregunta
All link layer protocols that support IP have the same frame structure (i.e., length of frame, number and length of header fields).
Pregunta 198
Pregunta
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?
Pregunta 199
Pregunta
For public-key certification, PGP uses certification authorities.
Pregunta 200
Pregunta
The 802.11 protocol does not implement collision detection because
Respuesta
-
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