CS 6250 EXAM 1 | COMPUTER NETWORK
EXAM 1 | QUESTIONS AND ANSWERS
RATED A+ | 2025/2026 GUIDE
T/F: assume hosts A, B, and C. Host A has a UDP socket with port 123.
Hosts B and C each send their own UDP segment to Host A. Hosts B
and C cannot use the same destination port 123 for sending their UDP
segment
- Correct Answer - false
T/F: TCP offers in order delivery of packets, flow control, and congestion
control
- Correct Answer - true
T/F: TCP detects packet loss using timeouts and triple duplicate
acknowledgements
- Correct Answer - true
T/F: flow control is a rate control mechanism to protect the receiver's
buffer from overflowing
- Correct Answer - true
,T/F: congestion control is a rate control mechanism to protect the
network from congestion
- Correct Answer - true
T/F: in TCP, the number of unacknowledged segments that a sender can
have is the minimum of the congestion window and the receive window
- Correct Answer - true
T/F: consider the following TCP Reno, congestion window is cut in half in
both of the following events:
a) a timeout occurs
b) a triple duplicate acknowledgement occurs
- Correct Answer - false
T/F: consider a TCP connection and a diagram that shows the
congestion as it progresses over time. From the diagram, when we
observe the congestion window to drop to its initial value, we infer that a
packet loss occurred
- Correct Answer - true
T/F: consider a TCP connection and a diagram that shows how the
congestion window progresses over time. from the diagram we can
identify the time periods of slow start when the congestion window
increases by 1 ever RTT - Correct Answer - false
, T/F: TCP cubic was designed for better network utilization - Correct
Answer - true
T/F: TCP cubic congestion window growth function is designed not to
overflow the receiver's buffer - Correct Answer - false
T/F: TCP cubic uses a cubic function to increase the congestion window
- Correct Answer - true
T/F: TCP cubic increases the congestion window in every RTT - Correct
Answer - false
UDP and TCP use port numbers to identify the sending application and
destination application; why don't UDP and TCP just use process IDs
rather than define port numbers? - Correct Answer - - process IDs are
specific to an os, making the protocol operating system dependent
- a single process can set up multiple channels of communications, so
couldn't properly demultiplex
- having processes run on well known ports is an important convention
why does UDP take 1's complement of the checksum instead of just the
sum?
how does the receiver compute and detect errors?
EXAM 1 | QUESTIONS AND ANSWERS
RATED A+ | 2025/2026 GUIDE
T/F: assume hosts A, B, and C. Host A has a UDP socket with port 123.
Hosts B and C each send their own UDP segment to Host A. Hosts B
and C cannot use the same destination port 123 for sending their UDP
segment
- Correct Answer - false
T/F: TCP offers in order delivery of packets, flow control, and congestion
control
- Correct Answer - true
T/F: TCP detects packet loss using timeouts and triple duplicate
acknowledgements
- Correct Answer - true
T/F: flow control is a rate control mechanism to protect the receiver's
buffer from overflowing
- Correct Answer - true
,T/F: congestion control is a rate control mechanism to protect the
network from congestion
- Correct Answer - true
T/F: in TCP, the number of unacknowledged segments that a sender can
have is the minimum of the congestion window and the receive window
- Correct Answer - true
T/F: consider the following TCP Reno, congestion window is cut in half in
both of the following events:
a) a timeout occurs
b) a triple duplicate acknowledgement occurs
- Correct Answer - false
T/F: consider a TCP connection and a diagram that shows the
congestion as it progresses over time. From the diagram, when we
observe the congestion window to drop to its initial value, we infer that a
packet loss occurred
- Correct Answer - true
T/F: consider a TCP connection and a diagram that shows how the
congestion window progresses over time. from the diagram we can
identify the time periods of slow start when the congestion window
increases by 1 ever RTT - Correct Answer - false
, T/F: TCP cubic was designed for better network utilization - Correct
Answer - true
T/F: TCP cubic congestion window growth function is designed not to
overflow the receiver's buffer - Correct Answer - false
T/F: TCP cubic uses a cubic function to increase the congestion window
- Correct Answer - true
T/F: TCP cubic increases the congestion window in every RTT - Correct
Answer - false
UDP and TCP use port numbers to identify the sending application and
destination application; why don't UDP and TCP just use process IDs
rather than define port numbers? - Correct Answer - - process IDs are
specific to an os, making the protocol operating system dependent
- a single process can set up multiple channels of communications, so
couldn't properly demultiplex
- having processes run on well known ports is an important convention
why does UDP take 1's complement of the checksum instead of just the
sum?
how does the receiver compute and detect errors?
