00:01
So in this question to solve this problem we need to understand how go back and works in tcp and how errors affect the transmission.
00:08
So for case a, the third segment is corrupted.
00:12
The sender segment 1, 2, 3 and receiver detects the corruption and discard the corrupted segment.
00:19
The sender transmits segment 3, 4, 5.
00:22
So the total number of segment sent out is 6.
00:25
For the case b, the third segment is correctly received but ack to the third segment is lost.
00:34
So in this case the sender segment sends 1, 2, 3 and receiver correctly receive all segment and segment 3 is lost.
00:44
So the sender upon timeout retransmit segment is 3, 4, 5 and the total number of segment sent out is 6 in this case also.
00:54
Now coming to this c case.
00:57
So case c, the eighth segment is lost.
01:00
So sender sends the segment up to 8, 1, 2, 8 and receiver upon detecting loss of the eighth segment.
01:09
So lastly correctly received segment is 7 and the sender upon timeout retransmit is 8, 9, 10...