Self doubt CN

Question

While calculating the sender window size in sliding window protocol why we don't include transmission time of first frame along with its propagation time of that frame and propagation time of Acknowledgement.

That is , total time to transmit the frames = Transmission time of first frame + 2* propagation delay

Instead we use only total time to transmit frames = 2* Propagation time .

Isn't this will cause change in answer a difference of 1 frame

Answer 1

we use total time( time taken between before transmitting the frame and after reaching the frame)=TT(transmission time)+2*PT(round trip time)

we can also calculate maximum window size of protocol =1+(2*PT)/TT

thus we include transmission time while calculating window size.