Question B$6$

In a network using the Go$-$Back$-$N protocol, assume $m=6$ and the window size is $63,$ the values of variables are $S_f=10,S_n=15$ and $R_n=13.$ Assume that the network does not duplicate or reorder the packets.

$($a$)$ What are the sequence numbers of data packets in transit?

$(1$ mark$)$

$($b$)$ At the sender$,$ what is the sequence number of the next packet to send?

$(1$ mark$)$

$($c$)$ If time$-$out happens. How many packets will be resent? What are their sequence numbers?

$(2$ marks$)$

$($d$)$ If the sender receives an ACK with ackNo $=12.$ What are the next values of $S_f$ and $S_n?$

$(2$ marks$)$

$($e$)$ At the receiver, a packet with sequence number $13$ arrives. What is the next value of $R_n?$ What ackNo should be sent by the receiver?

$(2$ marks$)$