I am working on homework assignment and I found a similar question and the answer that I can refer to.
On this website I am being presented the question and the solution. Question 1A:
http://www.ee.uwa.edu.au/~roberto/teach/ind426/handouts/tutorials/solutions/tute3.pdf
A channel has a data rate of 4kbps and a propagation delay of 20ms. Find the frame size in Stop-and-Wait to reach at least 50% of efficiency.
Where does the 80 come from? What is the value of L from here?
Please help!