$($i$)[0\mathrm{.}5]$ Consider the data transfer between two hosts A and B$,$ with the stop$-$and$-$wait protocol, rdt$3\mathrm{.}0.$ A is located on the West Coast of the United States and B is located on the East Coast. The speed$-$of$-$light round trip propagation delay between A and B$,$ RTT$,$ is approximately $30$ milliseconds. Suppose that A and B are connected by a channel with a transmission rate, R$,$ of $1$Gbps$.$ Given the packet size, L$,$ of $1500$ bytes, determine the channel utilization.

$($ii$)[0\mathrm{.}5]$ Following the problem $($i$),$ consider the pipelined technique instead of stop$-$and$-$wait protocol. How big would the window size have to be for the channel utilization to be greater than $98\%?$

$($iii$)[0\mathrm{.}25]$ What does the receive window $($rwnd$)$ field in a TCP segment indicate?