  We consider the adaptation of random early detection (RED) as an active queue
management algorithm for TCP traffic in Internet gateways where different
maximum transfer units (MTUs) are used. We studied the two existing RED
variants and point out a weakness in both. The first variant where the drop
probability is independent from the packet size discriminates connections with
smaller MTUs. The second variant results in a very high Packet Loss Ratio
(PLR), and as a consequence low goodput, for connections with higher MTUs. We
show that fairness in terms of loss and goodput can be supplied through an
appropriate setting of the RED algorithm.
