Answer:
The answer is "2".
Explanation:
In the given question some information is missing, that is "The propagation time for satellite to earth" which is "270 milliseconds" so, the description to this question can be defined as follows:
Given values:
Bandwidth = 64 kbps
Data frames = 512 bytes
Propagation Time (tp ) =270 ms
Change Bandwidth kbps to bps:
1 kb= 1024 bytes
calculated bandwidth= 64 kbps = 64×1024 bps = 65536 bps
1 bytes = 8 bits
512 bytes = 512 × 8 = 4096 bits
Frame length = 4096 bits
Formula
Transmission time (Tt) = Frame length /Bandwidth
Window size = 1+2a
where a = Propagation time/Transmission time
Calculate Transmission time:
Transmission time (Tt) = 4096 / 65536
Transmission time (Tt)= 625 m.sec
Calculate Window size:
Window size = 1+2(270/625)
Window size
= 1+2(0.432)
Window size
= 1+0.864
Window size = 1.864
Window size
= 2
