Data Communication and Net-Centric Computing (COSC1111) Assignment 2

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Data Communication and Net-Centric Computing (COSC1111)

Assignment 2 (30%)

Task 1 (12 marks)

•    Describe one of your team’s student ID (mixed odd and even decimal) using an array S(i),while i =1, 2, … , 7.

•    Run mod 2 operation to get the reminder corresponding to each digit of S(i).

•    Represent the 7-bit output as D =

1.  Use a tool to draw a flowchart shows the conversion from S(i) to D.     (4 marks)

2.  Create the even parity Hamming Code based on D = [D7 ,  … , D1]. Show the detailed calculation about how you get the even parity bits r8 , r4 , r2 , and r1 , then fill in following Table.      (4 marks)

3.  Suppose there is an error in position 11 at the receiving end, i.e. D7  (the opposite binary, e.g., D7  is “0” in the Table, then the received bit D7  is “ 1” in error). Other bits are correct. What is the codeword received at the receiving end?  (1 mark)

4.  Based on Hamming simulator, write a user manual (maximum 6-step) to show how to identify the error in position 11.   (3 marks)

Task 2 (10 marks)

1.  List 3-5 steps to explain how the frame check sequence (FCS) is used for error detection. Draw a figure to show how the receiver checks the error.       (4 marks)

2.  Which layer of the TCP/IP model associates with the FCS? Based on the figure you created in Task 2.1, explain how to ensure integrity in that layer?   (3 marks)

3.  Give an example to discuss how to trade-off the reliable data transmission and minimize latency when selecting the Transport layer protocols,.            (3 marks)

Task 3 (8 marks)

Create a table to compare the data link layer error control approaches: stop-and-wait, go-back-N ARQ, and selective repeat ARQ.(Negative ACK), include:

•   the mechanism of each error control approach.                                  (3 marks)

•   the resource required associates with each approach.                       (3 marks)

•   two advantages and two disadvantages of each approach.                (2 marks)