Transmission time for 1 frame=512 B/(64/8)KBps = 64 ms
- Propagation time = 270
- Roundtrip time = 2x270= 540ms
- Transmission time+ RTT =604 ms
a) Window size =1
means in 604 ms, only 1 frame is send
Throughput= 512 B/604 msec = 678 bps
b) Window size =7
means in 604 ms, 7 frames are send
Throughput= 7x512 B/604 msec = 7x678 bps = 4746 bps
c) We know maximum throughput is possible when Window size = [1+ 2Tpropagation /T transmision]
= 1+2 *270/64 =9.43 ~ 10
So Window size =15 will give throughput as maximum bandwidth available ie 64 Kbps
d) Window size =127
But maximum throughput is achieved when window size =10 onwards.
Hence Window size =127 also will give throughput as maximum bandwidth available ie 64 Kbps.
Therefore, Window size 15 and 127 have same throughput