Question

A host sends five packets and receives three acknowledgments. The time is shown as hour:minute:seconds. Segment 1 was sent at 0:0:00. Segment 2 was sent at 0:0:02. ACK for segments 1 and 2 received at 0:0:05. Segment 3 was sent at 0:0:06. Segment 4 was sent at 0:0:08. ACK for segments 3 and 4 received at 0:0:15. Segment 5 was sent at 0:0:16. and lost Segment 6 was sent at 0:0:17. and lost ACK for segments 5 and 6 received at 0:0:55. Segment 7 sent at 0:0:56. Ack of segment 7 received at 0:0:70 Calculate the values of RTTM, RTTS, RTTD, and RTO if the original RTO is 6 seconds. Did the sender miss the retransmission of any segment? Show which segments should have been retransmitted and when. What is the RTO value used for segment 7. Rewrite the events including the retransmission time.

Answer 1

Solution:

In the given question set, it is important to correct certain deadlock.

When sending TCP receives the information, it starts a persistence timer.

The segment contains about 1 byte data and has the given sequence number.

However, sequence number is never acknowledged in this case.

Hence, the probe resends the acknowledgement.