It is assumed that there are at least 40 packets buffered in the queue to be sent out by the sender, the network is stable (i.e., the propagation time between the sender and the server is roughly the same for every data packet and ack if it is not lost), the total transmission delay of 3 data packets are much smaller than RTT, 8-bit sequence numbers are used, window size N = 3, and initial send_base = 15.

Draw a diagram similar to PPT slide 25 titled Selective repeat in action of Chapter 3 for the Selective-Repeat approach to illustrate the interaction between the sender and the receiver between the moment when pkt15 is sent the first time by the sender and the moment when pkt 23 is sent out the first time by the sender. During the interaction, only four abnormal events occur: pkt16 is lost on the way when it is sent to the receiver the FIRST time, the timer for pkt16 expires a little while after ack#17 is received by the sender the FIRST time, , ack18 is lost on the way when it is sent to the sender the FIRST time, and the timer for pkt18 expires right after the pkt(s) with newly available sequence number(s) are sent out due to the event of receiving ack#16 by the sender the FIRST time.

a,What are the values of send_base, nextseqnum, and N in this particular case?

b, Selective repeat: sender, receiver windows What are the values of rcv_base and N in this particular case?

Selective repeat: sender, receiver windows send base nextsegnum usable, not already yet sent ack'e sent, not not usable yet ack ed t dow size t N E (a) sender view of sequence numbers out of order acceptable (buffered) but (within window) already ack ed Expected, not not usable yet received t window size t rcv base (b) receiver view of sequence numbers Selective repeat: sender, receiver windows send base nextsegnum usable, not already yet sent ack'e sent, not not usable yet ack ed t dow size t N E (a) sender view of sequence numbers out of order acceptable (buffered) but (within window) already ack ed Expected, not not usable yet received t window size t rcv base (b) receiver view of sequence numbers