In TCP Vegas, the calculation of ActualRate is done by dividing the amount of data transmitted in one RTT interval by the length of the RTT.

(a) Show that for any TCP, if the window size remains constant, then the amount of data transmitted in one RTT interval is constant once a full window-full is sent. Assume that the sender transmits each segment instantly upon receiving an ACK, packets are not lost and are delivered in order, segments are all the same size, and the first link along the path is not the slowest.

(b) Give a timeline sketch showing that the amount of data per RTT above can be less than CongestionWindow.