TCP Sequence and ACK numbers with segment loss Consider the

TCP Sequence and ACK numbers with segment loss: Consider the figure below in which TCP a sender and receiver communicate over a connection in which the sender-to-receiver segments may be lost. The TCP sender sends initial window of five segments at t = 1, 2, 3, 4, 5, respectively. Suppose the initial value of the sender to receiver sequence number is 137 and the first five segments each contain 508 bytes. The delay between the sender and the receiver is 7 time units, and so the first segment arrives at the receiver at t=8. As shown in the figure, two of the five segment(s) are lost between the sender and the receiver. Answer the following questions: Give the sequence numbers associated with each of the five segments sent by the sends. List the sequence of acknowledgements transmitted by the TCP receiver in response to the receipt of the segments actually received. In particular, give the value in the acknowledgement field of each receiver-sender acknowledgement, and give a brief explanation as to why that particular acknowledgement number value is being used

Solution

Sequence numbers related with five segments:

                              Sequence number                          range

Segment 1                     137                                         137 to 644

Segment 2                     645 645 to 1151

Segment 3                     1152                                       1152 to 1658

Segment 4                     1659                                       1659 to 2165

Segment 5                     2166                                       2166 to 2672