ASSIGNMENT-3
NETWORK ARCHITECTURE-1

Submitted by:
YENUGU SATHYADHARI
16190296

Compare GBN, SR and TCP(no delayed ACK).Assume that the timeout values for all three protocols are sufficiently long such that 7 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) respectively. Suppose Host A sends 7 data segments to Host B, and the 2nd segment (sent from A) is lost. In the end, all 7 segments have been correctly received by Host B. 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 the 3 protocols?
Sol:
Given 3 protocols …show more content…
Host A sends 7 packets to Host B, and A receives 7 acknowledgments if all the segments are reached correctly.
Suppose the 2nd segment sent from Host A to Host B is lost, then Host B sends acknowledgments of remaining all the 6 packets received correctly.
Hence, in this protocol Host A retransmits 2nd segment alone.
Total number of segments sent from A to B = 7+ 1 =8
Acknowledgments received from B to A = 6+1=7
If segments are assumed as PKT and acknowledgment as ACK then
Sequence number of segments sent from A to B = PKT1, PKT2, PKT3, PKT4, PKT5, PKT6, PKT7, PKT2
Sequence number of acknowledgments sent from B to A = ACK1, ACK3, ACK4, ACK5, ACK6, ACK7, ACK2

Transmission Control Protocol:
Suppose Host A sends 7 packets to Host B, host B sends acknowledgments of all the 7 segments if segments are received …show more content…
What are the sequence numbers of the first six segments in the TCP connection (including the segment containing the HTTP POST)? At what time was each segment sent? When was the ACK for each segment received? Given the difference between when each TCP segment was sent, and when its acknowledgement was received, what is the RTT value for each of the six segments? What is the EstimatedRTT value after the receipt of each ACK? Assume that the value of the EstimatedRTT is equal to the measured RTT for the first segment, and then is computed using the EstimatedRTT equation all subsequent segments. Note: Wireshark has a nice feature that allows you to plot the RTT for each of the TCP segments sent. Select a TCP segment in the “listing of captured packets” window that is being sent from the client to the gaia.cs.umass.edu server. Then select: Statistics->TCP Stream Graph->Round Trip Time