Business Data Communications and Networking Dennis and Fitzgerald Chapter 4
Question and Answer
media access control - Correct Answer:refers to the need to control when computers transmit
X-ON/X-OFF - Correct Answer:A flow control method in which the transmitting device will
continue to send data until the recipient tells it to stop. Once the recipient is once again ready to
receive data, it will send a message to the transmitting device that it is okay to resume.
polling - Correct Answer:the process of sending a signal to a client computer that gives it
permission to transmit or asks it to receive. clients store all messages that need to be transmitted.
The server periodically polls the client to see if it has data to send.
contention - Correct Answer:the opposite of controlled access. Computers wait until the circuit is
free and then transmit whenever they have data to send
roll-call polling - Correct Answer:controlled access method where controller works through a list
of clients, polling (asking) each if they want to transmit
hub polling(token passing) - Correct Answer:one computers starts the poll, passes it to another
on the multipoint circuit, sends its message and passes the poll to the next. process continues
until the first computer is reached again and then the process begins again.
human errors - Correct Answer:controlled through the application program
network errors - Correct Answer:controlled by the network hardware and software
Line noise and distortion - Correct Answer:in electrical media, such as twisted-pair wire and
coaxial cable, they are undesirable electrical signals. introduced by equipment or natural
disturbances.
line outages - Correct Answer:a catastrophic cause of errors and incomplete transmission
White Noise (Gaussian Noise) - Correct Answer:background hiss or static on radios and
telephones. caused by the thermal agitation of electrons and therefore is inescapable
impulse noise - Correct Answer:primary source of errors in data communications. can obliterate
a group of data, causing a burst error
cross-talk - Correct Answer:occurs when one circuit picks up signals in another. increases with
increased comms distance, increased proximity of two wires, increased signal strength and
higher frequency signals
echoes - Correct Answer:caused by poor connections which causes the singal to reflect back to
the transmitting equipment
Question and Answer
media access control - Correct Answer:refers to the need to control when computers transmit
X-ON/X-OFF - Correct Answer:A flow control method in which the transmitting device will
continue to send data until the recipient tells it to stop. Once the recipient is once again ready to
receive data, it will send a message to the transmitting device that it is okay to resume.
polling - Correct Answer:the process of sending a signal to a client computer that gives it
permission to transmit or asks it to receive. clients store all messages that need to be transmitted.
The server periodically polls the client to see if it has data to send.
contention - Correct Answer:the opposite of controlled access. Computers wait until the circuit is
free and then transmit whenever they have data to send
roll-call polling - Correct Answer:controlled access method where controller works through a list
of clients, polling (asking) each if they want to transmit
hub polling(token passing) - Correct Answer:one computers starts the poll, passes it to another
on the multipoint circuit, sends its message and passes the poll to the next. process continues
until the first computer is reached again and then the process begins again.
human errors - Correct Answer:controlled through the application program
network errors - Correct Answer:controlled by the network hardware and software
Line noise and distortion - Correct Answer:in electrical media, such as twisted-pair wire and
coaxial cable, they are undesirable electrical signals. introduced by equipment or natural
disturbances.
line outages - Correct Answer:a catastrophic cause of errors and incomplete transmission
White Noise (Gaussian Noise) - Correct Answer:background hiss or static on radios and
telephones. caused by the thermal agitation of electrons and therefore is inescapable
impulse noise - Correct Answer:primary source of errors in data communications. can obliterate
a group of data, causing a burst error
cross-talk - Correct Answer:occurs when one circuit picks up signals in another. increases with
increased comms distance, increased proximity of two wires, increased signal strength and
higher frequency signals
echoes - Correct Answer:caused by poor connections which causes the singal to reflect back to
the transmitting equipment
