Hello Hisham
Yes, I see your confusion. I believe that this will clarify what is meant by this sentence:
For the specific example in the lesson:
- for average queue depth values between 0 and 20, there are zero drops.
- for average queue depth values between 20 and 45 there is an increasing number of drops depending upon the queue depth.
- for average queue depth values exceeding 45, all packets are dropped.
For queue depth values between 20 and 45, the percentage of dropped packets goes from 0 to a maximum of 25%. The MPD is that value of 25%. This is also illustrated in the diagram in the lesson:
Indeed, as you say, for any value that exceeds an average queue depth of 45, all packets will be dropped.
I hope this has been helpful!
Laz