Programming Question

I am working on Computer science course and the subject is Advanced Network Systems answer all the questions briefly

Advanced Network System
Fall 2023
Homework 3
11:55 pm November 5, 2023
Reference textbook: Computer Networking: A Top-Down Approach, 8th Edition, by James F.
Kurose and Keith W. Ross, published by Pearson Education, Inc.
All homework assignments must be completed by each student individually. Any copying
of someone else’s work, or misrepresentation of other work as your own, will be grounds
for failing this assignment or the course.
Penalty for late work is 20 points per day late.
There are 6 questions; make sure you answer all these questions.
1. In protocol rdt3.0, the ACK packets flowing from the receiver to the sender do
not have sequence numbers (although they do have an ACK field that contains
the sequence number of the packet they are acknowledging). Why is it that our
ACK packets do not require sequence numbers?
2. Suppose that the five measured SampleRTT values (see Section 3.5.3) are 146
ms, 110 ms, 135 ms, 85 ms, and 92 ms. Compute the EstimatedRTT after
each of these SampleRTT values is obtained, using a value of α = 0.15 and
assuming that the value of EstimatedRTT was 120 ms just before the first of
these five samples were obtained. Compute also the DevRTT after each sample
is obtained, assuming a value of β = 0.3 and assuming the value of DevRTT was
7 ms just before the first of these five samples was obtained. Last, compute the
TCP TimeoutInterval after each of these samples is obtained.
3. Host A and B are communicating over a TCP connection, and Host B has
already received all bytes up through byte 473. Suppose Host A then sends two
segments to Host B back-to-back. The first and second segments contain 520
and 50 bytes of data, respectively. In the first segment, the sequence number is
474, the port number is 2350, and the destination port number is 4270. Host B
send an acknowledgement whenever it receives a segment from Host A.
a. In the second segment sent from Host A to Host B, what are the
sequence number, source port number, and destination port number?
b. If the second segment arrives before the first segment, in the
acknowledgement of the first arriving segment, what is the
acknowledgement number?
c. If the first segment arrives before the second segment, in the
acknowledgement of the first arriving segment, what are the
acknowledgement number, the source port number, and the destination
port number?
d. Suppose the two segments sent by A arrive in order at B. The first
acknowledgement is lost and the second acknowledgement arrives after
the first timeout interval. Draw a timing diagram, showing these segments
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and all other segments and acknowledgements sent. (Assume there is no
additional packet loss.) For each segment in your figure, provide the
sequence number and the number of bytes of data; for each
acknowledgement that you add, provide the acknowledgement number.
4. Consider the GBN and SR protocols. Suppose the sequence number space is of
size X. What is the largest allowable sender window that will avoid the
occurrence of problems such as that in Figure 3.27 in the above textbook for
each of these protocols?
5. Consider a TCP connection has an initial Threshold of 24 kB and a Maximum
Segment Size (MSS) of 4 kB. The receiver advertised window is 40 kB. Suppose
all transmission attempts are successful except for a triple duplicate ACK
received (for the same previously transmitted data) on the number 7 transmission
and a timeout at transmission number 12. The first transmission attempt is
number 0. Find the size of the sender’s congestion window for the first 18
transmission attempts (number 0-17) assuming the sender’s TCP implementation
is using the slow-start congestion control scheme.
6. Compare GBN, SR and TCP (no delayed ACK). Assume that the timeout values
for all three protocols are sufficiently long such that 10 consecutive data
segments and the corresponding ACKs can be received (if not lost in the
channel) by the receiving host (Host B) and the sending host (Host A)
respectively. Suppose Host A sends 10 data segments to Host B, and the fifth
segment (sent from A) is lost. In the end, all 10 data segments have been
correctly received by Host B.
a. How many segments has Host A sent in total and how many ACKs
has Host B sent in total? What are their sequence numbers? Answer
this question for all three protocols.
b. If the timeout values for all three protocols are much longer than 10
RTT, then which protocol successfully delivers all 10 data segments in
the shortest time interval?
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