Question

Multiple choice questions: Circle the correct answer

9) Suppose Host A sends four TCP segments back to back to Host B over a TCP connection. The sequence numbers in the four segments are 70, 90, 110, and 130, respectively. Suppose that the second segment is lost but all the other segments arrive at B. In the acknowledgement that Host B sends to Host A after the fourth segment arrives at B, the acknowledgement number is

(a) 70; (b) 90; (c) 110; (d) 130; (e) None of the above

Answer 1

Solution:

(9)

Given,

=>Number of segments = 4

=>Sequence number of first segment = 70

=>Sequence number of second segment = 90

=>Sequence number of third segment = 110

=>Sequence number of fourth segment = 130

=>Second segment is lost.

The answer will be an option,

(b) 90

Explanation:

=>Option (a) is wrong because acknowledgment number will be for the request of lost segment which is second segment and has sequence number 90 not 70.

=>Option (b) is correct because second segment is lost hence acknowledgement number will be same as the sequence numbe of second segment.

=>Option (c) is wrong because acknowledgment number will be for the request of lost segment which is second segment and has sequence number 90 not 110.

=>Option (d) is wrong because acknowledgment number will be for the request of lost segment which is second segment and has sequence number 90 not 130.

=>Option (e) is wrong because option (b) is correct.

I have explained each and every part with the help of statements attached to the answer above.