|Authors:||James F. Kurose, Keith W. Ross|
Compare GBN, SR, and TCP (no
delayed ACK). Assume that the timeout values for all three protocols
are sufficiently long such that 5 consecutive data segments and their
corresponding ACKs can be received (if not lost in the channel) by
the receiving host (Host B) and the sending host (Host A) respec-
tively. Suppose Host A sends 5 data segments to Host B, and the 2nd
segment (sent from A) is lost. In the end, all 5 data segments have
been correctly received by Host B.
a. How many segments has Host A sent in total and how many ACKs has Host B sent in total? What are their sequence numbers? Answer this question for all three protocols.
b. If the timeout values for all three protocol are much longer than 5 RTT, then which protocol successfully delivers all five data segments in shortest time interval?
If the timeout values for all three protocol are much longer than 5 RTT, then TCP protocol successfully delivers all five data segments in shortest time interval. The reason is that TCP uses fast retransmit without waiting time.