Random early detection

RED addresses these issues by pre-emptively dropping packets before the buffer becomes completely full.

[2] RED monitors the average queue size and drops (or marks when used in conjunction with ECN) packets based on statistical probabilities.

RED is more fair than tail drop, in the sense that it does not possess a bias against bursty traffic that uses only a small portion of the bandwidth.

If the average queue length oscillates around min threshold then early detection is too aggressive.

On the other hand, if the average queue length oscillates around max threshold then early detection is being too conservative.

[9] RRED algorithm can significantly improve the performance of TCP under Low-rate Denial-of-Service attacks.