CS 6250 EXAM 1| COMPUTER NETWORKS | QUESTIONS AND
ANSWERS | VERIFIED ANSWERS GRADED A+ | LATEST EXAM
UPDATE
(L1) How did Licklider and his team in the early 1960s experiment w/ a
precursor to the Internet?
Connecting two computers over a dial up telephone line
(L1) What is the Domain Name System design to do primarily?
Translate domain names into IP addresses
(L1) What is the architectural design of the Internet protocol stack based
on?
Layers
(L1) Both the data link and transport layer protocols may provide error
correction.
True
(L1) What allows for communication between application layer and
transport layer?
Sockets
(L1) Which of the follow protocols belong to the application layer?
UDP
DNS
IP
Ethernet
DNS
(L1) Which two protocols belong in the transport layer?
UDP & TCP
(L1) When an application sends a packet of information across the
network, this packet ravels down the IP stack and undergoes what process?
,Encapsulation
(L1) According to the end-to-end principle, where should most of the
Internet's functionality/intelligence be implemented?
At the edges of the network
(L1) What is the difference between hubs, bridges, and routers?
They operate at different layers of the IP stack.
(L2) The transport layer protocols offer a logical connection between
processes only if the hosts reside in the same network
False
(L2) A sending host receives a message from the application and
encapsulates it with the transport layer headers before passing it down to
the network layer.
True
(L2) An application running on a host can bind to multiple sockets
simultaneously.
True
(L2) The identifier of a UDP socket is a tuple of destination IP address and
port.
True
(L2) The identifier of a TCP socket is a tuple of source IP address and port.
False
(L2) UDP is considered more lightweight than TCP.
True
(L2) One of the functionalities that UDP offers is to increase or decrease the
pace with which the sender sends data to the receiver.
False
(L2) UDP offers basic error checking
True
,(L2) 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
False
(L2) TCP offers in-order delivery of the packets, flow control, and
congestion control.
True
(L2) TCP detects packet loss using timeouts and triple duplicate
acknowledgments.
True
(L2) Flow control is a rate control mechanism to protect the receiver's
buffer from overflowing
True
(L2) Congestion control is a rate control mechanism to protect the network
from congestion.
True
(L2) In TCP, the number of unacknowledged segments that a sender can
have is the minimum of the congestion window and the receive window.
True
(L2) Consider the TCP Reno, congestion window is cut in half in both of the
following events: a) a timeout occurs b) triple duplicate acknowledgement
occurs.
False
(L2) 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.
True
(L2) 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.
False
, (L2) TCP Cubic was designed for a better network utilization.
True
(L2) TCP Cubic congestion window growth function is designed to not
overflow the receiver's buffer.
False
(L2) TCP Cubic uses a cubic function to increase the congestion windw.
True
(L2) TCP Cubic increases the congestion window in every RTT.
False
(L3) "Routing" and "forwarding" are interchangeable terms
False
(L3) Consider a source and destination host. Before packets leave the
source host, the host needs to define the path over which the packets will
travel to reach the destination host.
False
(L3) Intradomain routing refers to routing that takes place among routers
that belong to the same admin domain. In contrast when routers belong to
different admin domains, we refer to routing as interdomain routing.
True
(L3) Consider the link-state routing protocol. The link costs are known to
all nodes.
True
(L3) Consider the link-state routing protocol. The network topology is
known to all nodes.
False
(L3) Consider the link-state routing protocol and a node u as our source
node. The goal of the algorithm is to compute the least-cost paths from the
source node u to every other node in the network.
True
(L3) Consider the link-state routing protocol with a node u as our source
node. Consider the initialization of the algorithm. We initialize the least-
ANSWERS | VERIFIED ANSWERS GRADED A+ | LATEST EXAM
UPDATE
(L1) How did Licklider and his team in the early 1960s experiment w/ a
precursor to the Internet?
Connecting two computers over a dial up telephone line
(L1) What is the Domain Name System design to do primarily?
Translate domain names into IP addresses
(L1) What is the architectural design of the Internet protocol stack based
on?
Layers
(L1) Both the data link and transport layer protocols may provide error
correction.
True
(L1) What allows for communication between application layer and
transport layer?
Sockets
(L1) Which of the follow protocols belong to the application layer?
UDP
DNS
IP
Ethernet
DNS
(L1) Which two protocols belong in the transport layer?
UDP & TCP
(L1) When an application sends a packet of information across the
network, this packet ravels down the IP stack and undergoes what process?
,Encapsulation
(L1) According to the end-to-end principle, where should most of the
Internet's functionality/intelligence be implemented?
At the edges of the network
(L1) What is the difference between hubs, bridges, and routers?
They operate at different layers of the IP stack.
(L2) The transport layer protocols offer a logical connection between
processes only if the hosts reside in the same network
False
(L2) A sending host receives a message from the application and
encapsulates it with the transport layer headers before passing it down to
the network layer.
True
(L2) An application running on a host can bind to multiple sockets
simultaneously.
True
(L2) The identifier of a UDP socket is a tuple of destination IP address and
port.
True
(L2) The identifier of a TCP socket is a tuple of source IP address and port.
False
(L2) UDP is considered more lightweight than TCP.
True
(L2) One of the functionalities that UDP offers is to increase or decrease the
pace with which the sender sends data to the receiver.
False
(L2) UDP offers basic error checking
True
,(L2) 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
False
(L2) TCP offers in-order delivery of the packets, flow control, and
congestion control.
True
(L2) TCP detects packet loss using timeouts and triple duplicate
acknowledgments.
True
(L2) Flow control is a rate control mechanism to protect the receiver's
buffer from overflowing
True
(L2) Congestion control is a rate control mechanism to protect the network
from congestion.
True
(L2) In TCP, the number of unacknowledged segments that a sender can
have is the minimum of the congestion window and the receive window.
True
(L2) Consider the TCP Reno, congestion window is cut in half in both of the
following events: a) a timeout occurs b) triple duplicate acknowledgement
occurs.
False
(L2) 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.
True
(L2) 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.
False
, (L2) TCP Cubic was designed for a better network utilization.
True
(L2) TCP Cubic congestion window growth function is designed to not
overflow the receiver's buffer.
False
(L2) TCP Cubic uses a cubic function to increase the congestion windw.
True
(L2) TCP Cubic increases the congestion window in every RTT.
False
(L3) "Routing" and "forwarding" are interchangeable terms
False
(L3) Consider a source and destination host. Before packets leave the
source host, the host needs to define the path over which the packets will
travel to reach the destination host.
False
(L3) Intradomain routing refers to routing that takes place among routers
that belong to the same admin domain. In contrast when routers belong to
different admin domains, we refer to routing as interdomain routing.
True
(L3) Consider the link-state routing protocol. The link costs are known to
all nodes.
True
(L3) Consider the link-state routing protocol. The network topology is
known to all nodes.
False
(L3) Consider the link-state routing protocol and a node u as our source
node. The goal of the algorithm is to compute the least-cost paths from the
source node u to every other node in the network.
True
(L3) Consider the link-state routing protocol with a node u as our source
node. Consider the initialization of the algorithm. We initialize the least-
