CS6250 Computer Networks Exam 1
Actual Exam Study Questions with
Correct Answers
1. What is the Domain Name System (DNS) designed to do primarily? -
ANSWER Translate domain names into IP addresses
2. How did Licklider and his team in the early 1960s experiment with a
precursor to the Internet? - ANSWER Connecting two computers over a
dial up telephone line
3. The identifier of a TCP socket is a tuple of source IP address and port -
ANSWER False
4. UDP is considered more lightweight than TCP - ANSWER True
5. One of the functionalities that UDP offers is to increase or decrease the pace
with which the sender sends data to the receiver - ANSWER False
6. UDP offers basic error checking - ANSWER True
7. 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 -
ANSWER False
,8. TCP offers in-order delivery of the packets, flow control, and congestion
control - ANSWER True
9. TCP detects packet loss using timeouts and triple duplicate
acknowledgements - ANSWER True
10.Flow control is a rate control mechanism to protect the receiver's buffer from
overflowing - ANSWER True
11.Congestion control is a rate control mechanism to protect the network from
congestion - ANSWER True
12.In TCP, the number of unacknowledged segments that a sender can have is
the minimum of the congestion window and the receive window. -
ANSWER True
13.Consider the TCP Reno, congestion window is cut in half in both of the
following events: a) a timeout occurs b) a triple duplicate acknowledgement
occurs - ANSWER False
14.Consider a TCP connection and a diagram showing the congestion as it
progresses. From the diagram, when we observe the congestion window
drop to its initial value, we infer that a packet loss occurred - ANSWER
True
15.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 every RTT.
- ANSWER False
,16.TCP Cubic was designed for better network utilization - ANSWER True
17.TCP Cubic congestion window growth function is designed to not overflow
the receiver's buffer - ANSWER False
18.TCP Cubic uses a cubic function to increase the congestion window -
ANSWER True
19.TCP Cubic increases the congestion window in every RTT - ANSWER
False
20."Routing" and "forwarding" are interchangeable terms - ANSWER False
21.What is the architectural design of the Internet protocol stack based on? -
ANSWER Layers
22.Both the data link and transports layer protocols may provide error
correction - ANSWER True
23.What allows for communication between the application layer and the
transport layer? - ANSWER Sockets
24.Which of the following protocols belong to the application layer?
Ethernet
IP (Internet Protocol)
, DNS (Domain Name Service)
UDP (User Datagram Protocol) - ANSWER DNS (Domain Name Service)
25.Which two protocols belong to the transport layer?
UDP
TCP
HTTP
IP - ANSWER UDP and TCP
26.When an application sends a packet of information across the network, this
packet travels down the IP stack and undergoes what process? - ANSWER
Encapsulation
27.According to the end-to-end principle, where should most of the Internet's
functionality/intelligence be implemented? - ANSWER At the edges of a
network
28.What is the difference between hubs, bridges, and routers? - ANSWER
They operate on different layers of the IP stack
Actual Exam Study Questions with
Correct Answers
1. What is the Domain Name System (DNS) designed to do primarily? -
ANSWER Translate domain names into IP addresses
2. How did Licklider and his team in the early 1960s experiment with a
precursor to the Internet? - ANSWER Connecting two computers over a
dial up telephone line
3. The identifier of a TCP socket is a tuple of source IP address and port -
ANSWER False
4. UDP is considered more lightweight than TCP - ANSWER True
5. One of the functionalities that UDP offers is to increase or decrease the pace
with which the sender sends data to the receiver - ANSWER False
6. UDP offers basic error checking - ANSWER True
7. 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 -
ANSWER False
,8. TCP offers in-order delivery of the packets, flow control, and congestion
control - ANSWER True
9. TCP detects packet loss using timeouts and triple duplicate
acknowledgements - ANSWER True
10.Flow control is a rate control mechanism to protect the receiver's buffer from
overflowing - ANSWER True
11.Congestion control is a rate control mechanism to protect the network from
congestion - ANSWER True
12.In TCP, the number of unacknowledged segments that a sender can have is
the minimum of the congestion window and the receive window. -
ANSWER True
13.Consider the TCP Reno, congestion window is cut in half in both of the
following events: a) a timeout occurs b) a triple duplicate acknowledgement
occurs - ANSWER False
14.Consider a TCP connection and a diagram showing the congestion as it
progresses. From the diagram, when we observe the congestion window
drop to its initial value, we infer that a packet loss occurred - ANSWER
True
15.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 every RTT.
- ANSWER False
,16.TCP Cubic was designed for better network utilization - ANSWER True
17.TCP Cubic congestion window growth function is designed to not overflow
the receiver's buffer - ANSWER False
18.TCP Cubic uses a cubic function to increase the congestion window -
ANSWER True
19.TCP Cubic increases the congestion window in every RTT - ANSWER
False
20."Routing" and "forwarding" are interchangeable terms - ANSWER False
21.What is the architectural design of the Internet protocol stack based on? -
ANSWER Layers
22.Both the data link and transports layer protocols may provide error
correction - ANSWER True
23.What allows for communication between the application layer and the
transport layer? - ANSWER Sockets
24.Which of the following protocols belong to the application layer?
Ethernet
IP (Internet Protocol)
, DNS (Domain Name Service)
UDP (User Datagram Protocol) - ANSWER DNS (Domain Name Service)
25.Which two protocols belong to the transport layer?
UDP
TCP
HTTP
IP - ANSWER UDP and TCP
26.When an application sends a packet of information across the network, this
packet travels down the IP stack and undergoes what process? - ANSWER
Encapsulation
27.According to the end-to-end principle, where should most of the Internet's
functionality/intelligence be implemented? - ANSWER At the edges of a
network
28.What is the difference between hubs, bridges, and routers? - ANSWER
They operate on different layers of the IP stack
