Random Early Detection and the Mark Probability Denominator

The denominator is the bottom end of a fraction. The numerator in the equation (top value) will be 1. This can also be viewed as a fraction. 1/10 is 1 out of 10.

random-detect precedence 5 40 90 5

This will look at IPPrec 5 packets. And will start discarding when the queue depth reaches 40. By the time the queue-depth reaches 90 (which yes, would need to have been increased first!) it will discard 1 of every 5 packets.

Ref: https://learningnetwork.cisco.com/thread/4439