Quiz 2: End-To-End Encryption Implementation

University:
American Baptist College
Course:
CIT380 | Computer and Network Security
Academic year:

2023
Views:

186

Pages:

2
Author:

RTerbayar

Quiz 2 1. Consider the TCP segment consisting of the HTTP POST method as the first segment of the TCP connection. a. What is the sequence number in the first 6 segments (including the segment containing the HTTP POST) and also the ACK number in the first 6 segments received! Answer: • Segment 1: 101307 • Segment 2: 102676 • Segment 3: 104045 • Segment 4: 105414 • Segment 5: 106783 • Segment 6: 109521 b. What is the time taken to send each segment? When is the ACK for each segment received? Given the difference between when each TCP segment is sent and when its ACK is received, what is the round trip time (RTT) value for each of the six segments? Formula: SampleRTT = ACK receive time - segment send time. (See the print book Computer Networking: A Top Down Approach 6th edition by Kurose Ross page 239). Answer: • Segment 1 = 4.597515 - 4. 201966 = 0.395549 • Segment 2 = 4.597518 - 4. 201994 = 0.395524 • Segment 3 = 4.597517 - 4. 202023 = 0.395494 • Segment 4 = 4.597520 - 4. 202051 = 0.395469 • Segment 5 = 4.597519 - 4. 202079 = 0.39544 • Segment 6 = 4.597521 - 4. 202134 = 0.395387 c. What is the EstimatedRTT value after the receipt of each ACK from the first segment to the 6th segment? Formula: EstimatedRTT = 0.875 * EstimatedRTT + 0.125 * SampleRTT. (See the printed book Computer Networking: A Top Down Approach 6th edition by Kurose Ross page 239). Answer: • Segment 1 = 0.875*0.395549 + 0.125*0.395549 = 0 .395549 lOMoARcPSD|26370826 • • • • • Segment 2 = 0.875*0.395524 + 0.125*0.395524 = 0 .395524 Segment 3 = 0.875 * 0.395494 + 0.125 * 0.395494 = 0 .395494 Segment 4 = 0.875 * 0.395469 + 0.125 * 0.395469 = 0 .395469 Segment 5 = 0.875*0.39544 + 0.125*0. 39544= 0 .39544 Segment 6 = 0.875 * 0.395387 + 0.125 * 0.395387 = 0 .395387 d. Notes: Wireshark has a feature to describe each TCP segment sent. Select the TCP segment in the "list of captured packets" that is being sent from your computer/laptop to the gaia.cs.umass.edu server. Then select Statistics TCP Stream Graph Round Trip Time Graph. Display the RTT Graph! Answer: 2. What is the segment length of each of the first 6 segments of TCP? Answer: a. Length: 1369