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ACS-3911 Computer Networks
University of Winnipeg. Lecturer: Dr. Beck
Assignment Sheet #3
Important Dates
Start of assignment period: November 7th, 2023
Deadline for submission: November 21st, 2023
IMPORTANT: You have to submit your solutions via Nexus. Your submission must clearly indicate
your name in each file you submit. Your submitted filenames must also clearly indicate to which
assignment they belong. For example, “Michael_Beck_A1-1.pdf”.
Keep an eye on Nexus for clarifications/corrections of this assignment.
The final result of your assignment will be available once our Teaching Assistant has corrected it.
Assignment 3.1
Suppose two clients (client A and client B) want to establish a Telnet connection with a server S at
the same time. Provide possible source and destination port numbers for:
1)
2)
3)
4)
The segments sent from A to S
The segments sent from B to S
The segments sent from S to A
The segments sent from S to B
If A and B are on different end-systems, is it possible that the source port number in the segments
sent from A to S is the same as that from B to S?
Is it possible if they are on the same end-system instead?
Hint: To solve this assignment you must look-up which transport layer protocol Telnet uses and
which port-numbers are assigned for Telnet
Assignment 3.2
Consider the sending side of the rdt.2.1 protocol as shown by the FSM diagram here:
Also consider a receiver as described by this FSM diagram:
Describe a situation in which the protocol gets deadlocked. Meaning that neither sender nor receiver
will change their behavior and no new data can be transmitted to the receiver. Also explain how we
can end up in this situation (i.e., under what circumstances we reach this deadlock).
Assignment 3.3
Consider the following forwarding table for an IPv4 network and a router with 4 links.
Attention: We use longest-prefix matching in this assignment!
Destination Address Range
11100000 00000000 00000000 00000000
through
11100000 00111111 11111111 11111111
11100000 01000000 00000000 00000000
through
11100000 01000000 11111111 11111111
11100000 01000001 00000000 00000000
through
11100001 01111111 11111111 11111111
Otherwise
Link Interface
0
1
2
3
Question 1: Describe how this forwarding table determines the appropriate link interface for
datagrams with the destination addresses:
•
•
•
11001000 10010001 01010001 01010101
11100000 01000000 11000011 00111100
11100001 10000000 00010001 01110111
Question 2: For each of the four interfaces, how many addresses lie in the respective address range?
(Hint: You can give your answer in powers of 2. For example, 210 − 25 would be sufficient, instead of
calculating the exact value 210 − 25 = 992)
Question 3: Give the first and last IP-address that is mapped to each Interface in dot-decimal
notation (for example 11111111 11111111 11111111 11111111 is 255.255.255.255 in dot-decimal
notation)
Question 4: Give the respective CIDR-notation for the range of link interface 0 and link interface 1
Question 5: Express the range of link interface 2 as two ranges in CIDR-notation
Assignment 3.4
Download the file “wireshark_assignment3.pdf” provided in week 11 on Nexus and read it carefully.
Answer the questions given in it. You must use your own wireshark-traces for this. If you cannot
create your own wireshark-traces contact Dr. Beck.
On Nexus you will also be asked to upload the wireshark-trace from which you derived your
solutions.
Purchase answer to see full
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