11/3/25, 1:37 PM Computer Networking
Computer Networking Newest Version 2025-2026 \Latest
Update with Complete questions and accurate answers
R1. Suppose the network layer a)
provides the following service. 4 Byte Destination Address
The network layer in the source 4 Byte Destination Port Number 1196 Bytes of Data
host accepts a segment of
maximum size 1,200 bytes and The network layer in the source host accepts a segment of
a destination host address from max size of 1200 bytes and a destination host address (4
the transport layer. The bytes) from the transport layer. So 1200 Bytes - 4 Byte Port
network layer then guarantees Number is 1196 Bytes of data per segment.
to deliver the segment to the
b)
transport layer at the
4 Byte Destination Address
destination host. Suppose many
4 Byte Destination Port
network application processes
Number 4 Byte Source
can be running at the
Address
destination host.
4 Byte Source Port
a. Design the simplest possible
Number 1188 Bytes of
transport- layer protocol that
Data
will get application data to the
desired process at the
1200 Bytes - 4 Byte Port Number - 4 Byte Source Address - 4
destination host. Assume the
Byte Source Port Number = 1188 Bytes of Data per segment.
operating system in the
destination host has assigned
c)
a 4-byte port number to each Not by itself, but routers and switches read the transport
running application process. layer header in order to deliver the data segment
b. Modify this protocol so that it properly to the destination host and application.
provides a "return address" to
the destination process.
c. In your protocols, does the
transport layer "have to do
anything" in the core of the
computer network?
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,11/3/25, 1:37 PM Computer Networking
R2. Consider a planet where a)
everyone belongs to a family This first strategy depends on a hierarchical structure.
of six, every family lives in Divide the planet into regions, the regions into sub-
its own house, each house regions, and keep dividing until you get to the house
has a unique address, and level. One of the family members delegates to the rest,
each person in a given and there is a person responsible for delivering mail to
house has a unique name. and from each sub-region within their region.
Suppose this planet has a
mail service that delivers The second strategy is a distributed structure. Give
letters from source house to each delegate a radius to operate in. Make the
destination house. The mail address on the envelope a GPS coordinate. Then have
service requires that (1) the each delegate pass an envelope the neighbor delegate
letter be in an envelope, that is closest to the destination address.
and that (2) the address of
the destination house (and b)
No, the only required information for delivery is
nothing more) be clearly
written in big letters on the envelope whereas the
written on the envelope.
letters contain no identifying information. In fact,
Suppose each family has a
opening the envelope to examine the letters will most
delegate family member
likely destroy this information.
who collects and distributes
letters for the other family
members. The letters do not
necessarily provide any
indication of the recipients
of the letters.
a. Using the solution to Problem
R1 above
as inspiration, describe a
protocol that the delegates
can use to deliver letters
from a sending family
member to a receiving
family member.
b. In your protocol, does the
mail service ever have to
open the envelope and
examine the letter in order
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,11/3/25, 1:37 PM Computer Networking
to provide its
service?
R3. Consider a TCP Source port number y and
connection between Host A destination port number x. [This is
and Host B. Suppose that The Reverse As Above]
the TCP segments traveling
from Host A to Host B have
source port number x and
destination port number y.
What are the source and
destination port numbers
for the segments
traveling from Host B to Host
A?
An application developer may not want its application
R4. Describe why an to use TCP's congestion control, which can throttle the
application developer might application's sending rate at times of congestion.
choose to run an application Often, designers of IP telephony and IP
over UDP rather than TCP. videoconference applications choose to run their
applications over UDP because they want to avoid
TCP's congestion control.
Also, some applications do not need the reliable data transfer
provided by TCP.
/ 3/124
, 11/3/25, 1:37 PM Computer Networking
R5. Why is it that voice and Since most firewalls are configured to block UDP traffic,
video traffic is often sent over using TCP for video and voice traffic lets the traffic
TCP rather than UDP in though the firewalls
today's Internet? (Hint: The
answer we are looking for
has nothing to do with TCP's
congestion-control
mechanism.)
R6. Is it possible for an Yes. The application developer can put reliable data
application to enjoy reliable transfer into the application layer protocol. This
data transfer even when the would require a significant amount of work and
application runs over UDP? If debugging,
so, how?
however.
R7. Suppose a process in Yes, both segments will be directed to the same
Host C has a UDP socket socket. For each received segment, at the socket
with port number 6789. interface, the operating system will provide the
Suppose both Host A and process with the IP addresses to determine the
Host B each send a UDP origins of the individual segments.
segment to Host C with
destination port number
6789. Will both of these
segments be directed to the
same socket at Host C? If
so, how will the process at
Host C know that these two
segments originated from
two different hosts?
/ 4/124
Computer Networking Newest Version 2025-2026 \Latest
Update with Complete questions and accurate answers
R1. Suppose the network layer a)
provides the following service. 4 Byte Destination Address
The network layer in the source 4 Byte Destination Port Number 1196 Bytes of Data
host accepts a segment of
maximum size 1,200 bytes and The network layer in the source host accepts a segment of
a destination host address from max size of 1200 bytes and a destination host address (4
the transport layer. The bytes) from the transport layer. So 1200 Bytes - 4 Byte Port
network layer then guarantees Number is 1196 Bytes of data per segment.
to deliver the segment to the
b)
transport layer at the
4 Byte Destination Address
destination host. Suppose many
4 Byte Destination Port
network application processes
Number 4 Byte Source
can be running at the
Address
destination host.
4 Byte Source Port
a. Design the simplest possible
Number 1188 Bytes of
transport- layer protocol that
Data
will get application data to the
desired process at the
1200 Bytes - 4 Byte Port Number - 4 Byte Source Address - 4
destination host. Assume the
Byte Source Port Number = 1188 Bytes of Data per segment.
operating system in the
destination host has assigned
c)
a 4-byte port number to each Not by itself, but routers and switches read the transport
running application process. layer header in order to deliver the data segment
b. Modify this protocol so that it properly to the destination host and application.
provides a "return address" to
the destination process.
c. In your protocols, does the
transport layer "have to do
anything" in the core of the
computer network?
/ 1/124
,11/3/25, 1:37 PM Computer Networking
R2. Consider a planet where a)
everyone belongs to a family This first strategy depends on a hierarchical structure.
of six, every family lives in Divide the planet into regions, the regions into sub-
its own house, each house regions, and keep dividing until you get to the house
has a unique address, and level. One of the family members delegates to the rest,
each person in a given and there is a person responsible for delivering mail to
house has a unique name. and from each sub-region within their region.
Suppose this planet has a
mail service that delivers The second strategy is a distributed structure. Give
letters from source house to each delegate a radius to operate in. Make the
destination house. The mail address on the envelope a GPS coordinate. Then have
service requires that (1) the each delegate pass an envelope the neighbor delegate
letter be in an envelope, that is closest to the destination address.
and that (2) the address of
the destination house (and b)
No, the only required information for delivery is
nothing more) be clearly
written in big letters on the envelope whereas the
written on the envelope.
letters contain no identifying information. In fact,
Suppose each family has a
opening the envelope to examine the letters will most
delegate family member
likely destroy this information.
who collects and distributes
letters for the other family
members. The letters do not
necessarily provide any
indication of the recipients
of the letters.
a. Using the solution to Problem
R1 above
as inspiration, describe a
protocol that the delegates
can use to deliver letters
from a sending family
member to a receiving
family member.
b. In your protocol, does the
mail service ever have to
open the envelope and
examine the letter in order
/ 2/124
,11/3/25, 1:37 PM Computer Networking
to provide its
service?
R3. Consider a TCP Source port number y and
connection between Host A destination port number x. [This is
and Host B. Suppose that The Reverse As Above]
the TCP segments traveling
from Host A to Host B have
source port number x and
destination port number y.
What are the source and
destination port numbers
for the segments
traveling from Host B to Host
A?
An application developer may not want its application
R4. Describe why an to use TCP's congestion control, which can throttle the
application developer might application's sending rate at times of congestion.
choose to run an application Often, designers of IP telephony and IP
over UDP rather than TCP. videoconference applications choose to run their
applications over UDP because they want to avoid
TCP's congestion control.
Also, some applications do not need the reliable data transfer
provided by TCP.
/ 3/124
, 11/3/25, 1:37 PM Computer Networking
R5. Why is it that voice and Since most firewalls are configured to block UDP traffic,
video traffic is often sent over using TCP for video and voice traffic lets the traffic
TCP rather than UDP in though the firewalls
today's Internet? (Hint: The
answer we are looking for
has nothing to do with TCP's
congestion-control
mechanism.)
R6. Is it possible for an Yes. The application developer can put reliable data
application to enjoy reliable transfer into the application layer protocol. This
data transfer even when the would require a significant amount of work and
application runs over UDP? If debugging,
so, how?
however.
R7. Suppose a process in Yes, both segments will be directed to the same
Host C has a UDP socket socket. For each received segment, at the socket
with port number 6789. interface, the operating system will provide the
Suppose both Host A and process with the IP addresses to determine the
Host B each send a UDP origins of the individual segments.
segment to Host C with
destination port number
6789. Will both of these
segments be directed to the
same socket at Host C? If
so, how will the process at
Host C know that these two
segments originated from
two different hosts?
/ 4/124
